xref: /freebsd/stand/libsa/zfs/zfsimpl.c (revision e5e345a4b0aa9ac50ed23f90851fc5c68e94e0fd)
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 __FBSDID("$FreeBSD$");
29 
30 /*
31  *	Stand-alone ZFS file reader.
32  */
33 
34 #include <stdbool.h>
35 #include <sys/endian.h>
36 #include <sys/stat.h>
37 #include <sys/stdint.h>
38 #include <sys/list.h>
39 #include <sys/zfs_bootenv.h>
40 #include <machine/_inttypes.h>
41 
42 #include "zfsimpl.h"
43 #include "zfssubr.c"
44 
45 #ifdef HAS_ZSTD_ZFS
46 extern int zstd_init(void);
47 #endif
48 
49 struct zfsmount {
50 	char			*path;
51 	const spa_t		*spa;
52 	objset_phys_t		objset;
53 	uint64_t		rootobj;
54 	STAILQ_ENTRY(zfsmount)	next;
55 };
56 
57 typedef STAILQ_HEAD(zfs_mnt_list, zfsmount) zfs_mnt_list_t;
58 static zfs_mnt_list_t zfsmount = STAILQ_HEAD_INITIALIZER(zfsmount);
59 
60 /*
61  * The indirect_child_t represents the vdev that we will read from, when we
62  * need to read all copies of the data (e.g. for scrub or reconstruction).
63  * For plain (non-mirror) top-level vdevs (i.e. is_vdev is not a mirror),
64  * ic_vdev is the same as is_vdev.  However, for mirror top-level vdevs,
65  * ic_vdev is a child of the mirror.
66  */
67 typedef struct indirect_child {
68 	void *ic_data;
69 	vdev_t *ic_vdev;
70 } indirect_child_t;
71 
72 /*
73  * The indirect_split_t represents one mapped segment of an i/o to the
74  * indirect vdev. For non-split (contiguously-mapped) blocks, there will be
75  * only one indirect_split_t, with is_split_offset==0 and is_size==io_size.
76  * For split blocks, there will be several of these.
77  */
78 typedef struct indirect_split {
79 	list_node_t is_node; /* link on iv_splits */
80 
81 	/*
82 	 * is_split_offset is the offset into the i/o.
83 	 * This is the sum of the previous splits' is_size's.
84 	 */
85 	uint64_t is_split_offset;
86 
87 	vdev_t *is_vdev; /* top-level vdev */
88 	uint64_t is_target_offset; /* offset on is_vdev */
89 	uint64_t is_size;
90 	int is_children; /* number of entries in is_child[] */
91 
92 	/*
93 	 * is_good_child is the child that we are currently using to
94 	 * attempt reconstruction.
95 	 */
96 	int is_good_child;
97 
98 	indirect_child_t is_child[1]; /* variable-length */
99 } indirect_split_t;
100 
101 /*
102  * The indirect_vsd_t is associated with each i/o to the indirect vdev.
103  * It is the "Vdev-Specific Data" in the zio_t's io_vsd.
104  */
105 typedef struct indirect_vsd {
106 	boolean_t iv_split_block;
107 	boolean_t iv_reconstruct;
108 
109 	list_t iv_splits; /* list of indirect_split_t's */
110 } indirect_vsd_t;
111 
112 /*
113  * List of all vdevs, chained through v_alllink.
114  */
115 static vdev_list_t zfs_vdevs;
116 
117 /*
118  * List of ZFS features supported for read
119  */
120 static const char *features_for_read[] = {
121 	"com.datto:bookmark_v2",
122 	"com.datto:encryption",
123 	"com.datto:resilver_defer",
124 	"com.delphix:bookmark_written",
125 	"com.delphix:device_removal",
126 	"com.delphix:embedded_data",
127 	"com.delphix:extensible_dataset",
128 	"com.delphix:head_errlog",
129 	"com.delphix:hole_birth",
130 	"com.delphix:obsolete_counts",
131 	"com.delphix:spacemap_histogram",
132 	"com.delphix:spacemap_v2",
133 	"com.delphix:zpool_checkpoint",
134 	"com.intel:allocation_classes",
135 	"com.joyent:multi_vdev_crash_dump",
136 	"com.klarasystems:vdev_zaps_v2",
137 	"org.freebsd:zstd_compress",
138 	"org.illumos:lz4_compress",
139 	"org.illumos:sha512",
140 	"org.illumos:skein",
141 	"org.open-zfs:large_blocks",
142 	"org.openzfs:blake3",
143 	"org.zfsonlinux:allocation_classes",
144 	"org.zfsonlinux:large_dnode",
145 	NULL
146 };
147 
148 /*
149  * List of all pools, chained through spa_link.
150  */
151 static spa_list_t zfs_pools;
152 
153 static const dnode_phys_t *dnode_cache_obj;
154 static uint64_t dnode_cache_bn;
155 static char *dnode_cache_buf;
156 
157 static int zio_read(const spa_t *spa, const blkptr_t *bp, void *buf);
158 static int zfs_get_root(const spa_t *spa, uint64_t *objid);
159 static int zfs_rlookup(const spa_t *spa, uint64_t objnum, char *result);
160 static int zap_lookup(const spa_t *spa, const dnode_phys_t *dnode,
161     const char *name, uint64_t integer_size, uint64_t num_integers,
162     void *value);
163 static int objset_get_dnode(const spa_t *, const objset_phys_t *, uint64_t,
164     dnode_phys_t *);
165 static int dnode_read(const spa_t *, const dnode_phys_t *, off_t, void *,
166     size_t);
167 static int vdev_indirect_read(vdev_t *, const blkptr_t *, void *, off_t,
168     size_t);
169 static int vdev_mirror_read(vdev_t *, const blkptr_t *, void *, off_t, size_t);
170 vdev_indirect_mapping_t *vdev_indirect_mapping_open(spa_t *, objset_phys_t *,
171     uint64_t);
172 vdev_indirect_mapping_entry_phys_t *
173     vdev_indirect_mapping_duplicate_adjacent_entries(vdev_t *, uint64_t,
174     uint64_t, uint64_t *);
175 
176 static void
177 zfs_init(void)
178 {
179 	STAILQ_INIT(&zfs_vdevs);
180 	STAILQ_INIT(&zfs_pools);
181 
182 	dnode_cache_buf = malloc(SPA_MAXBLOCKSIZE);
183 
184 	zfs_init_crc();
185 #ifdef HAS_ZSTD_ZFS
186 	zstd_init();
187 #endif
188 }
189 
190 static int
191 nvlist_check_features_for_read(nvlist_t *nvl)
192 {
193 	nvlist_t *features = NULL;
194 	nvs_data_t *data;
195 	nvp_header_t *nvp;
196 	nv_string_t *nvp_name;
197 	int rc;
198 
199 	rc = nvlist_find(nvl, ZPOOL_CONFIG_FEATURES_FOR_READ,
200 	    DATA_TYPE_NVLIST, NULL, &features, NULL);
201 	switch (rc) {
202 	case 0:
203 		break;		/* Continue with checks */
204 
205 	case ENOENT:
206 		return (0);	/* All features are disabled */
207 
208 	default:
209 		return (rc);	/* Error while reading nvlist */
210 	}
211 
212 	data = (nvs_data_t *)features->nv_data;
213 	nvp = &data->nvl_pair;	/* first pair in nvlist */
214 
215 	while (nvp->encoded_size != 0 && nvp->decoded_size != 0) {
216 		int i, found;
217 
218 		nvp_name = (nv_string_t *)((uintptr_t)nvp + sizeof(*nvp));
219 		found = 0;
220 
221 		for (i = 0; features_for_read[i] != NULL; i++) {
222 			if (memcmp(nvp_name->nv_data, features_for_read[i],
223 			    nvp_name->nv_size) == 0) {
224 				found = 1;
225 				break;
226 			}
227 		}
228 
229 		if (!found) {
230 			printf("ZFS: unsupported feature: %.*s\n",
231 			    nvp_name->nv_size, nvp_name->nv_data);
232 			rc = EIO;
233 		}
234 		nvp = (nvp_header_t *)((uint8_t *)nvp + nvp->encoded_size);
235 	}
236 	nvlist_destroy(features);
237 
238 	return (rc);
239 }
240 
241 static int
242 vdev_read_phys(vdev_t *vdev, const blkptr_t *bp, void *buf,
243     off_t offset, size_t size)
244 {
245 	size_t psize;
246 	int rc;
247 
248 	if (vdev->v_phys_read == NULL)
249 		return (ENOTSUP);
250 
251 	if (bp) {
252 		psize = BP_GET_PSIZE(bp);
253 	} else {
254 		psize = size;
255 	}
256 
257 	rc = vdev->v_phys_read(vdev, vdev->v_priv, offset, buf, psize);
258 	if (rc == 0) {
259 		if (bp != NULL)
260 			rc = zio_checksum_verify(vdev->v_spa, bp, buf);
261 	}
262 
263 	return (rc);
264 }
265 
266 static int
267 vdev_write_phys(vdev_t *vdev, void *buf, off_t offset, size_t size)
268 {
269 	if (vdev->v_phys_write == NULL)
270 		return (ENOTSUP);
271 
272 	return (vdev->v_phys_write(vdev, offset, buf, size));
273 }
274 
275 typedef struct remap_segment {
276 	vdev_t *rs_vd;
277 	uint64_t rs_offset;
278 	uint64_t rs_asize;
279 	uint64_t rs_split_offset;
280 	list_node_t rs_node;
281 } remap_segment_t;
282 
283 static remap_segment_t *
284 rs_alloc(vdev_t *vd, uint64_t offset, uint64_t asize, uint64_t split_offset)
285 {
286 	remap_segment_t *rs = malloc(sizeof (remap_segment_t));
287 
288 	if (rs != NULL) {
289 		rs->rs_vd = vd;
290 		rs->rs_offset = offset;
291 		rs->rs_asize = asize;
292 		rs->rs_split_offset = split_offset;
293 	}
294 
295 	return (rs);
296 }
297 
298 vdev_indirect_mapping_t *
299 vdev_indirect_mapping_open(spa_t *spa, objset_phys_t *os,
300     uint64_t mapping_object)
301 {
302 	vdev_indirect_mapping_t *vim;
303 	vdev_indirect_mapping_phys_t *vim_phys;
304 	int rc;
305 
306 	vim = calloc(1, sizeof (*vim));
307 	if (vim == NULL)
308 		return (NULL);
309 
310 	vim->vim_dn = calloc(1, sizeof (*vim->vim_dn));
311 	if (vim->vim_dn == NULL) {
312 		free(vim);
313 		return (NULL);
314 	}
315 
316 	rc = objset_get_dnode(spa, os, mapping_object, vim->vim_dn);
317 	if (rc != 0) {
318 		free(vim->vim_dn);
319 		free(vim);
320 		return (NULL);
321 	}
322 
323 	vim->vim_spa = spa;
324 	vim->vim_phys = malloc(sizeof (*vim->vim_phys));
325 	if (vim->vim_phys == NULL) {
326 		free(vim->vim_dn);
327 		free(vim);
328 		return (NULL);
329 	}
330 
331 	vim_phys = (vdev_indirect_mapping_phys_t *)DN_BONUS(vim->vim_dn);
332 	*vim->vim_phys = *vim_phys;
333 
334 	vim->vim_objset = os;
335 	vim->vim_object = mapping_object;
336 	vim->vim_entries = NULL;
337 
338 	vim->vim_havecounts =
339 	    (vim->vim_dn->dn_bonuslen > VDEV_INDIRECT_MAPPING_SIZE_V0);
340 
341 	return (vim);
342 }
343 
344 /*
345  * Compare an offset with an indirect mapping entry; there are three
346  * possible scenarios:
347  *
348  *     1. The offset is "less than" the mapping entry; meaning the
349  *        offset is less than the source offset of the mapping entry. In
350  *        this case, there is no overlap between the offset and the
351  *        mapping entry and -1 will be returned.
352  *
353  *     2. The offset is "greater than" the mapping entry; meaning the
354  *        offset is greater than the mapping entry's source offset plus
355  *        the entry's size. In this case, there is no overlap between
356  *        the offset and the mapping entry and 1 will be returned.
357  *
358  *        NOTE: If the offset is actually equal to the entry's offset
359  *        plus size, this is considered to be "greater" than the entry,
360  *        and this case applies (i.e. 1 will be returned). Thus, the
361  *        entry's "range" can be considered to be inclusive at its
362  *        start, but exclusive at its end: e.g. [src, src + size).
363  *
364  *     3. The last case to consider is if the offset actually falls
365  *        within the mapping entry's range. If this is the case, the
366  *        offset is considered to be "equal to" the mapping entry and
367  *        0 will be returned.
368  *
369  *        NOTE: If the offset is equal to the entry's source offset,
370  *        this case applies and 0 will be returned. If the offset is
371  *        equal to the entry's source plus its size, this case does
372  *        *not* apply (see "NOTE" above for scenario 2), and 1 will be
373  *        returned.
374  */
375 static int
376 dva_mapping_overlap_compare(const void *v_key, const void *v_array_elem)
377 {
378 	const uint64_t *key = v_key;
379 	const vdev_indirect_mapping_entry_phys_t *array_elem =
380 	    v_array_elem;
381 	uint64_t src_offset = DVA_MAPPING_GET_SRC_OFFSET(array_elem);
382 
383 	if (*key < src_offset) {
384 		return (-1);
385 	} else if (*key < src_offset + DVA_GET_ASIZE(&array_elem->vimep_dst)) {
386 		return (0);
387 	} else {
388 		return (1);
389 	}
390 }
391 
392 /*
393  * Return array entry.
394  */
395 static vdev_indirect_mapping_entry_phys_t *
396 vdev_indirect_mapping_entry(vdev_indirect_mapping_t *vim, uint64_t index)
397 {
398 	uint64_t size;
399 	off_t offset = 0;
400 	int rc;
401 
402 	if (vim->vim_phys->vimp_num_entries == 0)
403 		return (NULL);
404 
405 	if (vim->vim_entries == NULL) {
406 		uint64_t bsize;
407 
408 		bsize = vim->vim_dn->dn_datablkszsec << SPA_MINBLOCKSHIFT;
409 		size = vim->vim_phys->vimp_num_entries *
410 		    sizeof (*vim->vim_entries);
411 		if (size > bsize) {
412 			size = bsize / sizeof (*vim->vim_entries);
413 			size *= sizeof (*vim->vim_entries);
414 		}
415 		vim->vim_entries = malloc(size);
416 		if (vim->vim_entries == NULL)
417 			return (NULL);
418 		vim->vim_num_entries = size / sizeof (*vim->vim_entries);
419 		offset = index * sizeof (*vim->vim_entries);
420 	}
421 
422 	/* We have data in vim_entries */
423 	if (offset == 0) {
424 		if (index >= vim->vim_entry_offset &&
425 		    index <= vim->vim_entry_offset + vim->vim_num_entries) {
426 			index -= vim->vim_entry_offset;
427 			return (&vim->vim_entries[index]);
428 		}
429 		offset = index * sizeof (*vim->vim_entries);
430 	}
431 
432 	vim->vim_entry_offset = index;
433 	size = vim->vim_num_entries * sizeof (*vim->vim_entries);
434 	rc = dnode_read(vim->vim_spa, vim->vim_dn, offset, vim->vim_entries,
435 	    size);
436 	if (rc != 0) {
437 		/* Read error, invalidate vim_entries. */
438 		free(vim->vim_entries);
439 		vim->vim_entries = NULL;
440 		return (NULL);
441 	}
442 	index -= vim->vim_entry_offset;
443 	return (&vim->vim_entries[index]);
444 }
445 
446 /*
447  * Returns the mapping entry for the given offset.
448  *
449  * It's possible that the given offset will not be in the mapping table
450  * (i.e. no mapping entries contain this offset), in which case, the
451  * return value depends on the "next_if_missing" parameter.
452  *
453  * If the offset is not found in the table and "next_if_missing" is
454  * B_FALSE, then NULL will always be returned. The behavior is intended
455  * to allow consumers to get the entry corresponding to the offset
456  * parameter, iff the offset overlaps with an entry in the table.
457  *
458  * If the offset is not found in the table and "next_if_missing" is
459  * B_TRUE, then the entry nearest to the given offset will be returned,
460  * such that the entry's source offset is greater than the offset
461  * passed in (i.e. the "next" mapping entry in the table is returned, if
462  * the offset is missing from the table). If there are no entries whose
463  * source offset is greater than the passed in offset, NULL is returned.
464  */
465 static vdev_indirect_mapping_entry_phys_t *
466 vdev_indirect_mapping_entry_for_offset(vdev_indirect_mapping_t *vim,
467     uint64_t offset)
468 {
469 	ASSERT(vim->vim_phys->vimp_num_entries > 0);
470 
471 	vdev_indirect_mapping_entry_phys_t *entry;
472 
473 	uint64_t last = vim->vim_phys->vimp_num_entries - 1;
474 	uint64_t base = 0;
475 
476 	/*
477 	 * We don't define these inside of the while loop because we use
478 	 * their value in the case that offset isn't in the mapping.
479 	 */
480 	uint64_t mid;
481 	int result;
482 
483 	while (last >= base) {
484 		mid = base + ((last - base) >> 1);
485 
486 		entry = vdev_indirect_mapping_entry(vim, mid);
487 		if (entry == NULL)
488 			break;
489 		result = dva_mapping_overlap_compare(&offset, entry);
490 
491 		if (result == 0) {
492 			break;
493 		} else if (result < 0) {
494 			last = mid - 1;
495 		} else {
496 			base = mid + 1;
497 		}
498 	}
499 	return (entry);
500 }
501 
502 /*
503  * Given an indirect vdev and an extent on that vdev, it duplicates the
504  * physical entries of the indirect mapping that correspond to the extent
505  * to a new array and returns a pointer to it. In addition, copied_entries
506  * is populated with the number of mapping entries that were duplicated.
507  *
508  * Finally, since we are doing an allocation, it is up to the caller to
509  * free the array allocated in this function.
510  */
511 vdev_indirect_mapping_entry_phys_t *
512 vdev_indirect_mapping_duplicate_adjacent_entries(vdev_t *vd, uint64_t offset,
513     uint64_t asize, uint64_t *copied_entries)
514 {
515 	vdev_indirect_mapping_entry_phys_t *duplicate_mappings = NULL;
516 	vdev_indirect_mapping_t *vim = vd->v_mapping;
517 	uint64_t entries = 0;
518 
519 	vdev_indirect_mapping_entry_phys_t *first_mapping =
520 	    vdev_indirect_mapping_entry_for_offset(vim, offset);
521 	ASSERT3P(first_mapping, !=, NULL);
522 
523 	vdev_indirect_mapping_entry_phys_t *m = first_mapping;
524 	while (asize > 0) {
525 		uint64_t size = DVA_GET_ASIZE(&m->vimep_dst);
526 		uint64_t inner_offset = offset - DVA_MAPPING_GET_SRC_OFFSET(m);
527 		uint64_t inner_size = MIN(asize, size - inner_offset);
528 
529 		offset += inner_size;
530 		asize -= inner_size;
531 		entries++;
532 		m++;
533 	}
534 
535 	size_t copy_length = entries * sizeof (*first_mapping);
536 	duplicate_mappings = malloc(copy_length);
537 	if (duplicate_mappings != NULL)
538 		bcopy(first_mapping, duplicate_mappings, copy_length);
539 	else
540 		entries = 0;
541 
542 	*copied_entries = entries;
543 
544 	return (duplicate_mappings);
545 }
546 
547 static vdev_t *
548 vdev_lookup_top(spa_t *spa, uint64_t vdev)
549 {
550 	vdev_t *rvd;
551 	vdev_list_t *vlist;
552 
553 	vlist = &spa->spa_root_vdev->v_children;
554 	STAILQ_FOREACH(rvd, vlist, v_childlink)
555 		if (rvd->v_id == vdev)
556 			break;
557 
558 	return (rvd);
559 }
560 
561 /*
562  * This is a callback for vdev_indirect_remap() which allocates an
563  * indirect_split_t for each split segment and adds it to iv_splits.
564  */
565 static void
566 vdev_indirect_gather_splits(uint64_t split_offset, vdev_t *vd, uint64_t offset,
567     uint64_t size, void *arg)
568 {
569 	int n = 1;
570 	zio_t *zio = arg;
571 	indirect_vsd_t *iv = zio->io_vsd;
572 
573 	if (vd->v_read == vdev_indirect_read)
574 		return;
575 
576 	if (vd->v_read == vdev_mirror_read)
577 		n = vd->v_nchildren;
578 
579 	indirect_split_t *is =
580 	    malloc(offsetof(indirect_split_t, is_child[n]));
581 	if (is == NULL) {
582 		zio->io_error = ENOMEM;
583 		return;
584 	}
585 	bzero(is, offsetof(indirect_split_t, is_child[n]));
586 
587 	is->is_children = n;
588 	is->is_size = size;
589 	is->is_split_offset = split_offset;
590 	is->is_target_offset = offset;
591 	is->is_vdev = vd;
592 
593 	/*
594 	 * Note that we only consider multiple copies of the data for
595 	 * *mirror* vdevs.  We don't for "replacing" or "spare" vdevs, even
596 	 * though they use the same ops as mirror, because there's only one
597 	 * "good" copy under the replacing/spare.
598 	 */
599 	if (vd->v_read == vdev_mirror_read) {
600 		int i = 0;
601 		vdev_t *kid;
602 
603 		STAILQ_FOREACH(kid, &vd->v_children, v_childlink) {
604 			is->is_child[i++].ic_vdev = kid;
605 		}
606 	} else {
607 		is->is_child[0].ic_vdev = vd;
608 	}
609 
610 	list_insert_tail(&iv->iv_splits, is);
611 }
612 
613 static void
614 vdev_indirect_remap(vdev_t *vd, uint64_t offset, uint64_t asize, void *arg)
615 {
616 	list_t stack;
617 	spa_t *spa = vd->v_spa;
618 	zio_t *zio = arg;
619 	remap_segment_t *rs;
620 
621 	list_create(&stack, sizeof (remap_segment_t),
622 	    offsetof(remap_segment_t, rs_node));
623 
624 	rs = rs_alloc(vd, offset, asize, 0);
625 	if (rs == NULL) {
626 		printf("vdev_indirect_remap: out of memory.\n");
627 		zio->io_error = ENOMEM;
628 	}
629 	for (; rs != NULL; rs = list_remove_head(&stack)) {
630 		vdev_t *v = rs->rs_vd;
631 		uint64_t num_entries = 0;
632 		/* vdev_indirect_mapping_t *vim = v->v_mapping; */
633 		vdev_indirect_mapping_entry_phys_t *mapping =
634 		    vdev_indirect_mapping_duplicate_adjacent_entries(v,
635 		    rs->rs_offset, rs->rs_asize, &num_entries);
636 
637 		if (num_entries == 0)
638 			zio->io_error = ENOMEM;
639 
640 		for (uint64_t i = 0; i < num_entries; i++) {
641 			vdev_indirect_mapping_entry_phys_t *m = &mapping[i];
642 			uint64_t size = DVA_GET_ASIZE(&m->vimep_dst);
643 			uint64_t dst_offset = DVA_GET_OFFSET(&m->vimep_dst);
644 			uint64_t dst_vdev = DVA_GET_VDEV(&m->vimep_dst);
645 			uint64_t inner_offset = rs->rs_offset -
646 			    DVA_MAPPING_GET_SRC_OFFSET(m);
647 			uint64_t inner_size =
648 			    MIN(rs->rs_asize, size - inner_offset);
649 			vdev_t *dst_v = vdev_lookup_top(spa, dst_vdev);
650 
651 			if (dst_v->v_read == vdev_indirect_read) {
652 				remap_segment_t *o;
653 
654 				o = rs_alloc(dst_v, dst_offset + inner_offset,
655 				    inner_size, rs->rs_split_offset);
656 				if (o == NULL) {
657 					printf("vdev_indirect_remap: "
658 					    "out of memory.\n");
659 					zio->io_error = ENOMEM;
660 					break;
661 				}
662 
663 				list_insert_head(&stack, o);
664 			}
665 			vdev_indirect_gather_splits(rs->rs_split_offset, dst_v,
666 			    dst_offset + inner_offset,
667 			    inner_size, arg);
668 
669 			/*
670 			 * vdev_indirect_gather_splits can have memory
671 			 * allocation error, we can not recover from it.
672 			 */
673 			if (zio->io_error != 0)
674 				break;
675 			rs->rs_offset += inner_size;
676 			rs->rs_asize -= inner_size;
677 			rs->rs_split_offset += inner_size;
678 		}
679 
680 		free(mapping);
681 		free(rs);
682 		if (zio->io_error != 0)
683 			break;
684 	}
685 
686 	list_destroy(&stack);
687 }
688 
689 static void
690 vdev_indirect_map_free(zio_t *zio)
691 {
692 	indirect_vsd_t *iv = zio->io_vsd;
693 	indirect_split_t *is;
694 
695 	while ((is = list_head(&iv->iv_splits)) != NULL) {
696 		for (int c = 0; c < is->is_children; c++) {
697 			indirect_child_t *ic = &is->is_child[c];
698 			free(ic->ic_data);
699 		}
700 		list_remove(&iv->iv_splits, is);
701 		free(is);
702 	}
703 	free(iv);
704 }
705 
706 static int
707 vdev_indirect_read(vdev_t *vdev, const blkptr_t *bp, void *buf,
708     off_t offset, size_t bytes)
709 {
710 	zio_t zio;
711 	spa_t *spa = vdev->v_spa;
712 	indirect_vsd_t *iv;
713 	indirect_split_t *first;
714 	int rc = EIO;
715 
716 	iv = calloc(1, sizeof(*iv));
717 	if (iv == NULL)
718 		return (ENOMEM);
719 
720 	list_create(&iv->iv_splits,
721 	    sizeof (indirect_split_t), offsetof(indirect_split_t, is_node));
722 
723 	bzero(&zio, sizeof(zio));
724 	zio.io_spa = spa;
725 	zio.io_bp = (blkptr_t *)bp;
726 	zio.io_data = buf;
727 	zio.io_size = bytes;
728 	zio.io_offset = offset;
729 	zio.io_vd = vdev;
730 	zio.io_vsd = iv;
731 
732 	if (vdev->v_mapping == NULL) {
733 		vdev_indirect_config_t *vic;
734 
735 		vic = &vdev->vdev_indirect_config;
736 		vdev->v_mapping = vdev_indirect_mapping_open(spa,
737 		    spa->spa_mos, vic->vic_mapping_object);
738 	}
739 
740 	vdev_indirect_remap(vdev, offset, bytes, &zio);
741 	if (zio.io_error != 0)
742 		return (zio.io_error);
743 
744 	first = list_head(&iv->iv_splits);
745 	if (first->is_size == zio.io_size) {
746 		/*
747 		 * This is not a split block; we are pointing to the entire
748 		 * data, which will checksum the same as the original data.
749 		 * Pass the BP down so that the child i/o can verify the
750 		 * checksum, and try a different location if available
751 		 * (e.g. on a mirror).
752 		 *
753 		 * While this special case could be handled the same as the
754 		 * general (split block) case, doing it this way ensures
755 		 * that the vast majority of blocks on indirect vdevs
756 		 * (which are not split) are handled identically to blocks
757 		 * on non-indirect vdevs.  This allows us to be less strict
758 		 * about performance in the general (but rare) case.
759 		 */
760 		rc = first->is_vdev->v_read(first->is_vdev, zio.io_bp,
761 		    zio.io_data, first->is_target_offset, bytes);
762 	} else {
763 		iv->iv_split_block = B_TRUE;
764 		/*
765 		 * Read one copy of each split segment, from the
766 		 * top-level vdev.  Since we don't know the
767 		 * checksum of each split individually, the child
768 		 * zio can't ensure that we get the right data.
769 		 * E.g. if it's a mirror, it will just read from a
770 		 * random (healthy) leaf vdev.  We have to verify
771 		 * the checksum in vdev_indirect_io_done().
772 		 */
773 		for (indirect_split_t *is = list_head(&iv->iv_splits);
774 		    is != NULL; is = list_next(&iv->iv_splits, is)) {
775 			char *ptr = zio.io_data;
776 
777 			rc = is->is_vdev->v_read(is->is_vdev, zio.io_bp,
778 			    ptr + is->is_split_offset, is->is_target_offset,
779 			    is->is_size);
780 		}
781 		if (zio_checksum_verify(spa, zio.io_bp, zio.io_data))
782 			rc = ECKSUM;
783 		else
784 			rc = 0;
785 	}
786 
787 	vdev_indirect_map_free(&zio);
788 	if (rc == 0)
789 		rc = zio.io_error;
790 
791 	return (rc);
792 }
793 
794 static int
795 vdev_disk_read(vdev_t *vdev, const blkptr_t *bp, void *buf,
796     off_t offset, size_t bytes)
797 {
798 
799 	return (vdev_read_phys(vdev, bp, buf,
800 	    offset + VDEV_LABEL_START_SIZE, bytes));
801 }
802 
803 static int
804 vdev_missing_read(vdev_t *vdev __unused, const blkptr_t *bp __unused,
805     void *buf __unused, off_t offset __unused, size_t bytes __unused)
806 {
807 
808 	return (ENOTSUP);
809 }
810 
811 static int
812 vdev_mirror_read(vdev_t *vdev, const blkptr_t *bp, void *buf,
813     off_t offset, size_t bytes)
814 {
815 	vdev_t *kid;
816 	int rc;
817 
818 	rc = EIO;
819 	STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
820 		if (kid->v_state != VDEV_STATE_HEALTHY)
821 			continue;
822 		rc = kid->v_read(kid, bp, buf, offset, bytes);
823 		if (!rc)
824 			return (0);
825 	}
826 
827 	return (rc);
828 }
829 
830 static int
831 vdev_replacing_read(vdev_t *vdev, const blkptr_t *bp, void *buf,
832     off_t offset, size_t bytes)
833 {
834 	vdev_t *kid;
835 
836 	/*
837 	 * Here we should have two kids:
838 	 * First one which is the one we are replacing and we can trust
839 	 * only this one to have valid data, but it might not be present.
840 	 * Second one is that one we are replacing with. It is most likely
841 	 * healthy, but we can't trust it has needed data, so we won't use it.
842 	 */
843 	kid = STAILQ_FIRST(&vdev->v_children);
844 	if (kid == NULL)
845 		return (EIO);
846 	if (kid->v_state != VDEV_STATE_HEALTHY)
847 		return (EIO);
848 	return (kid->v_read(kid, bp, buf, offset, bytes));
849 }
850 
851 static vdev_t *
852 vdev_find(uint64_t guid)
853 {
854 	vdev_t *vdev;
855 
856 	STAILQ_FOREACH(vdev, &zfs_vdevs, v_alllink)
857 		if (vdev->v_guid == guid)
858 			return (vdev);
859 
860 	return (0);
861 }
862 
863 static vdev_t *
864 vdev_create(uint64_t guid, vdev_read_t *_read)
865 {
866 	vdev_t *vdev;
867 	vdev_indirect_config_t *vic;
868 
869 	vdev = calloc(1, sizeof(vdev_t));
870 	if (vdev != NULL) {
871 		STAILQ_INIT(&vdev->v_children);
872 		vdev->v_guid = guid;
873 		vdev->v_read = _read;
874 
875 		/*
876 		 * root vdev has no read function, we use this fact to
877 		 * skip setting up data we do not need for root vdev.
878 		 * We only point root vdev from spa.
879 		 */
880 		if (_read != NULL) {
881 			vic = &vdev->vdev_indirect_config;
882 			vic->vic_prev_indirect_vdev = UINT64_MAX;
883 			STAILQ_INSERT_TAIL(&zfs_vdevs, vdev, v_alllink);
884 		}
885 	}
886 
887 	return (vdev);
888 }
889 
890 static void
891 vdev_set_initial_state(vdev_t *vdev, const nvlist_t *nvlist)
892 {
893 	uint64_t is_offline, is_faulted, is_degraded, is_removed, isnt_present;
894 	uint64_t is_log;
895 
896 	is_offline = is_removed = is_faulted = is_degraded = isnt_present = 0;
897 	is_log = 0;
898 	(void) nvlist_find(nvlist, ZPOOL_CONFIG_OFFLINE, DATA_TYPE_UINT64, NULL,
899 	    &is_offline, NULL);
900 	(void) nvlist_find(nvlist, ZPOOL_CONFIG_REMOVED, DATA_TYPE_UINT64, NULL,
901 	    &is_removed, NULL);
902 	(void) nvlist_find(nvlist, ZPOOL_CONFIG_FAULTED, DATA_TYPE_UINT64, NULL,
903 	    &is_faulted, NULL);
904 	(void) nvlist_find(nvlist, ZPOOL_CONFIG_DEGRADED, DATA_TYPE_UINT64,
905 	    NULL, &is_degraded, NULL);
906 	(void) nvlist_find(nvlist, ZPOOL_CONFIG_NOT_PRESENT, DATA_TYPE_UINT64,
907 	    NULL, &isnt_present, NULL);
908 	(void) nvlist_find(nvlist, ZPOOL_CONFIG_IS_LOG, DATA_TYPE_UINT64, NULL,
909 	    &is_log, NULL);
910 
911 	if (is_offline != 0)
912 		vdev->v_state = VDEV_STATE_OFFLINE;
913 	else if (is_removed != 0)
914 		vdev->v_state = VDEV_STATE_REMOVED;
915 	else if (is_faulted != 0)
916 		vdev->v_state = VDEV_STATE_FAULTED;
917 	else if (is_degraded != 0)
918 		vdev->v_state = VDEV_STATE_DEGRADED;
919 	else if (isnt_present != 0)
920 		vdev->v_state = VDEV_STATE_CANT_OPEN;
921 
922 	vdev->v_islog = is_log != 0;
923 }
924 
925 static int
926 vdev_init(uint64_t guid, const nvlist_t *nvlist, vdev_t **vdevp)
927 {
928 	uint64_t id, ashift, asize, nparity;
929 	const char *path;
930 	const char *type;
931 	int len, pathlen;
932 	char *name;
933 	vdev_t *vdev;
934 
935 	if (nvlist_find(nvlist, ZPOOL_CONFIG_ID, DATA_TYPE_UINT64, NULL, &id,
936 	    NULL) ||
937 	    nvlist_find(nvlist, ZPOOL_CONFIG_TYPE, DATA_TYPE_STRING, NULL,
938 	    &type, &len)) {
939 		return (ENOENT);
940 	}
941 
942 	if (memcmp(type, VDEV_TYPE_MIRROR, len) != 0 &&
943 	    memcmp(type, VDEV_TYPE_DISK, len) != 0 &&
944 #ifdef ZFS_TEST
945 	    memcmp(type, VDEV_TYPE_FILE, len) != 0 &&
946 #endif
947 	    memcmp(type, VDEV_TYPE_RAIDZ, len) != 0 &&
948 	    memcmp(type, VDEV_TYPE_INDIRECT, len) != 0 &&
949 	    memcmp(type, VDEV_TYPE_REPLACING, len) != 0 &&
950 	    memcmp(type, VDEV_TYPE_HOLE, len) != 0) {
951 		printf("ZFS: can only boot from disk, mirror, raidz1, "
952 		    "raidz2 and raidz3 vdevs, got: %.*s\n", len, type);
953 		return (EIO);
954 	}
955 
956 	if (memcmp(type, VDEV_TYPE_MIRROR, len) == 0)
957 		vdev = vdev_create(guid, vdev_mirror_read);
958 	else if (memcmp(type, VDEV_TYPE_RAIDZ, len) == 0)
959 		vdev = vdev_create(guid, vdev_raidz_read);
960 	else if (memcmp(type, VDEV_TYPE_REPLACING, len) == 0)
961 		vdev = vdev_create(guid, vdev_replacing_read);
962 	else if (memcmp(type, VDEV_TYPE_INDIRECT, len) == 0) {
963 		vdev_indirect_config_t *vic;
964 
965 		vdev = vdev_create(guid, vdev_indirect_read);
966 		if (vdev != NULL) {
967 			vdev->v_state = VDEV_STATE_HEALTHY;
968 			vic = &vdev->vdev_indirect_config;
969 
970 			nvlist_find(nvlist,
971 			    ZPOOL_CONFIG_INDIRECT_OBJECT,
972 			    DATA_TYPE_UINT64,
973 			    NULL, &vic->vic_mapping_object, NULL);
974 			nvlist_find(nvlist,
975 			    ZPOOL_CONFIG_INDIRECT_BIRTHS,
976 			    DATA_TYPE_UINT64,
977 			    NULL, &vic->vic_births_object, NULL);
978 			nvlist_find(nvlist,
979 			    ZPOOL_CONFIG_PREV_INDIRECT_VDEV,
980 			    DATA_TYPE_UINT64,
981 			    NULL, &vic->vic_prev_indirect_vdev, NULL);
982 		}
983 	} else if (memcmp(type, VDEV_TYPE_HOLE, len) == 0) {
984 		vdev = vdev_create(guid, vdev_missing_read);
985 	} else {
986 		vdev = vdev_create(guid, vdev_disk_read);
987 	}
988 
989 	if (vdev == NULL)
990 		return (ENOMEM);
991 
992 	vdev_set_initial_state(vdev, nvlist);
993 	vdev->v_id = id;
994 	if (nvlist_find(nvlist, ZPOOL_CONFIG_ASHIFT,
995 	    DATA_TYPE_UINT64, NULL, &ashift, NULL) == 0)
996 		vdev->v_ashift = ashift;
997 
998 	if (nvlist_find(nvlist, ZPOOL_CONFIG_ASIZE,
999 	    DATA_TYPE_UINT64, NULL, &asize, NULL) == 0) {
1000 		vdev->v_psize = asize +
1001 		    VDEV_LABEL_START_SIZE + VDEV_LABEL_END_SIZE;
1002 	}
1003 
1004 	if (nvlist_find(nvlist, ZPOOL_CONFIG_NPARITY,
1005 	    DATA_TYPE_UINT64, NULL, &nparity, NULL) == 0)
1006 		vdev->v_nparity = nparity;
1007 
1008 	if (nvlist_find(nvlist, ZPOOL_CONFIG_PATH,
1009 	    DATA_TYPE_STRING, NULL, &path, &pathlen) == 0) {
1010 		char prefix[] = "/dev/";
1011 
1012 		len = strlen(prefix);
1013 		if (len < pathlen && memcmp(path, prefix, len) == 0) {
1014 			path += len;
1015 			pathlen -= len;
1016 		}
1017 		name = malloc(pathlen + 1);
1018 		bcopy(path, name, pathlen);
1019 		name[pathlen] = '\0';
1020 		vdev->v_name = name;
1021 	} else {
1022 		name = NULL;
1023 		if (memcmp(type, VDEV_TYPE_RAIDZ, len) == 0) {
1024 			if (vdev->v_nparity < 1 ||
1025 			    vdev->v_nparity > 3) {
1026 				printf("ZFS: invalid raidz parity: %d\n",
1027 				    vdev->v_nparity);
1028 				return (EIO);
1029 			}
1030 			(void) asprintf(&name, "%.*s%d-%" PRIu64, len, type,
1031 			    vdev->v_nparity, id);
1032 		} else {
1033 			(void) asprintf(&name, "%.*s-%" PRIu64, len, type, id);
1034 		}
1035 		vdev->v_name = name;
1036 	}
1037 	*vdevp = vdev;
1038 	return (0);
1039 }
1040 
1041 /*
1042  * Find slot for vdev. We return either NULL to signal to use
1043  * STAILQ_INSERT_HEAD, or we return link element to be used with
1044  * STAILQ_INSERT_AFTER.
1045  */
1046 static vdev_t *
1047 vdev_find_previous(vdev_t *top_vdev, vdev_t *vdev)
1048 {
1049 	vdev_t *v, *previous;
1050 
1051 	if (STAILQ_EMPTY(&top_vdev->v_children))
1052 		return (NULL);
1053 
1054 	previous = NULL;
1055 	STAILQ_FOREACH(v, &top_vdev->v_children, v_childlink) {
1056 		if (v->v_id > vdev->v_id)
1057 			return (previous);
1058 
1059 		if (v->v_id == vdev->v_id)
1060 			return (v);
1061 
1062 		if (v->v_id < vdev->v_id)
1063 			previous = v;
1064 	}
1065 	return (previous);
1066 }
1067 
1068 static size_t
1069 vdev_child_count(vdev_t *vdev)
1070 {
1071 	vdev_t *v;
1072 	size_t count;
1073 
1074 	count = 0;
1075 	STAILQ_FOREACH(v, &vdev->v_children, v_childlink) {
1076 		count++;
1077 	}
1078 	return (count);
1079 }
1080 
1081 /*
1082  * Insert vdev into top_vdev children list. List is ordered by v_id.
1083  */
1084 static void
1085 vdev_insert(vdev_t *top_vdev, vdev_t *vdev)
1086 {
1087 	vdev_t *previous;
1088 	size_t count;
1089 
1090 	/*
1091 	 * The top level vdev can appear in random order, depending how
1092 	 * the firmware is presenting the disk devices.
1093 	 * However, we will insert vdev to create list ordered by v_id,
1094 	 * so we can use either STAILQ_INSERT_HEAD or STAILQ_INSERT_AFTER
1095 	 * as STAILQ does not have insert before.
1096 	 */
1097 	previous = vdev_find_previous(top_vdev, vdev);
1098 
1099 	if (previous == NULL) {
1100 		STAILQ_INSERT_HEAD(&top_vdev->v_children, vdev, v_childlink);
1101 	} else if (previous->v_id == vdev->v_id) {
1102 		/*
1103 		 * This vdev was configured from label config,
1104 		 * do not insert duplicate.
1105 		 */
1106 		return;
1107 	} else {
1108 		STAILQ_INSERT_AFTER(&top_vdev->v_children, previous, vdev,
1109 		    v_childlink);
1110 	}
1111 
1112 	count = vdev_child_count(top_vdev);
1113 	if (top_vdev->v_nchildren < count)
1114 		top_vdev->v_nchildren = count;
1115 }
1116 
1117 static int
1118 vdev_from_nvlist(spa_t *spa, uint64_t top_guid, const nvlist_t *nvlist)
1119 {
1120 	vdev_t *top_vdev, *vdev;
1121 	nvlist_t **kids = NULL;
1122 	int rc, nkids;
1123 
1124 	/* Get top vdev. */
1125 	top_vdev = vdev_find(top_guid);
1126 	if (top_vdev == NULL) {
1127 		rc = vdev_init(top_guid, nvlist, &top_vdev);
1128 		if (rc != 0)
1129 			return (rc);
1130 		top_vdev->v_spa = spa;
1131 		top_vdev->v_top = top_vdev;
1132 		vdev_insert(spa->spa_root_vdev, top_vdev);
1133 	}
1134 
1135 	/* Add children if there are any. */
1136 	rc = nvlist_find(nvlist, ZPOOL_CONFIG_CHILDREN, DATA_TYPE_NVLIST_ARRAY,
1137 	    &nkids, &kids, NULL);
1138 	if (rc == 0) {
1139 		for (int i = 0; i < nkids; i++) {
1140 			uint64_t guid;
1141 
1142 			rc = nvlist_find(kids[i], ZPOOL_CONFIG_GUID,
1143 			    DATA_TYPE_UINT64, NULL, &guid, NULL);
1144 			if (rc != 0)
1145 				goto done;
1146 
1147 			rc = vdev_init(guid, kids[i], &vdev);
1148 			if (rc != 0)
1149 				goto done;
1150 
1151 			vdev->v_spa = spa;
1152 			vdev->v_top = top_vdev;
1153 			vdev_insert(top_vdev, vdev);
1154 		}
1155 	} else {
1156 		/*
1157 		 * When there are no children, nvlist_find() does return
1158 		 * error, reset it because leaf devices have no children.
1159 		 */
1160 		rc = 0;
1161 	}
1162 done:
1163 	if (kids != NULL) {
1164 		for (int i = 0; i < nkids; i++)
1165 			nvlist_destroy(kids[i]);
1166 		free(kids);
1167 	}
1168 
1169 	return (rc);
1170 }
1171 
1172 static int
1173 vdev_init_from_label(spa_t *spa, const nvlist_t *nvlist)
1174 {
1175 	uint64_t pool_guid, top_guid;
1176 	nvlist_t *vdevs;
1177 	int rc;
1178 
1179 	if (nvlist_find(nvlist, ZPOOL_CONFIG_POOL_GUID, DATA_TYPE_UINT64,
1180 	    NULL, &pool_guid, NULL) ||
1181 	    nvlist_find(nvlist, ZPOOL_CONFIG_TOP_GUID, DATA_TYPE_UINT64,
1182 	    NULL, &top_guid, NULL) ||
1183 	    nvlist_find(nvlist, ZPOOL_CONFIG_VDEV_TREE, DATA_TYPE_NVLIST,
1184 	    NULL, &vdevs, NULL)) {
1185 		printf("ZFS: can't find vdev details\n");
1186 		return (ENOENT);
1187 	}
1188 
1189 	rc = vdev_from_nvlist(spa, top_guid, vdevs);
1190 	nvlist_destroy(vdevs);
1191 	return (rc);
1192 }
1193 
1194 static void
1195 vdev_set_state(vdev_t *vdev)
1196 {
1197 	vdev_t *kid;
1198 	int good_kids;
1199 	int bad_kids;
1200 
1201 	STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
1202 		vdev_set_state(kid);
1203 	}
1204 
1205 	/*
1206 	 * A mirror or raidz is healthy if all its kids are healthy. A
1207 	 * mirror is degraded if any of its kids is healthy; a raidz
1208 	 * is degraded if at most nparity kids are offline.
1209 	 */
1210 	if (STAILQ_FIRST(&vdev->v_children)) {
1211 		good_kids = 0;
1212 		bad_kids = 0;
1213 		STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
1214 			if (kid->v_state == VDEV_STATE_HEALTHY)
1215 				good_kids++;
1216 			else
1217 				bad_kids++;
1218 		}
1219 		if (bad_kids == 0) {
1220 			vdev->v_state = VDEV_STATE_HEALTHY;
1221 		} else {
1222 			if (vdev->v_read == vdev_mirror_read) {
1223 				if (good_kids) {
1224 					vdev->v_state = VDEV_STATE_DEGRADED;
1225 				} else {
1226 					vdev->v_state = VDEV_STATE_OFFLINE;
1227 				}
1228 			} else if (vdev->v_read == vdev_raidz_read) {
1229 				if (bad_kids > vdev->v_nparity) {
1230 					vdev->v_state = VDEV_STATE_OFFLINE;
1231 				} else {
1232 					vdev->v_state = VDEV_STATE_DEGRADED;
1233 				}
1234 			}
1235 		}
1236 	}
1237 }
1238 
1239 static int
1240 vdev_update_from_nvlist(uint64_t top_guid, const nvlist_t *nvlist)
1241 {
1242 	vdev_t *vdev;
1243 	nvlist_t **kids = NULL;
1244 	int rc, nkids;
1245 
1246 	/* Update top vdev. */
1247 	vdev = vdev_find(top_guid);
1248 	if (vdev != NULL)
1249 		vdev_set_initial_state(vdev, nvlist);
1250 
1251 	/* Update children if there are any. */
1252 	rc = nvlist_find(nvlist, ZPOOL_CONFIG_CHILDREN, DATA_TYPE_NVLIST_ARRAY,
1253 	    &nkids, &kids, NULL);
1254 	if (rc == 0) {
1255 		for (int i = 0; i < nkids; i++) {
1256 			uint64_t guid;
1257 
1258 			rc = nvlist_find(kids[i], ZPOOL_CONFIG_GUID,
1259 			    DATA_TYPE_UINT64, NULL, &guid, NULL);
1260 			if (rc != 0)
1261 				break;
1262 
1263 			vdev = vdev_find(guid);
1264 			if (vdev != NULL)
1265 				vdev_set_initial_state(vdev, kids[i]);
1266 		}
1267 	} else {
1268 		rc = 0;
1269 	}
1270 	if (kids != NULL) {
1271 		for (int i = 0; i < nkids; i++)
1272 			nvlist_destroy(kids[i]);
1273 		free(kids);
1274 	}
1275 
1276 	return (rc);
1277 }
1278 
1279 static int
1280 vdev_init_from_nvlist(spa_t *spa, const nvlist_t *nvlist)
1281 {
1282 	uint64_t pool_guid, vdev_children;
1283 	nvlist_t *vdevs = NULL, **kids = NULL;
1284 	int rc, nkids;
1285 
1286 	if (nvlist_find(nvlist, ZPOOL_CONFIG_POOL_GUID, DATA_TYPE_UINT64,
1287 	    NULL, &pool_guid, NULL) ||
1288 	    nvlist_find(nvlist, ZPOOL_CONFIG_VDEV_CHILDREN, DATA_TYPE_UINT64,
1289 	    NULL, &vdev_children, NULL) ||
1290 	    nvlist_find(nvlist, ZPOOL_CONFIG_VDEV_TREE, DATA_TYPE_NVLIST,
1291 	    NULL, &vdevs, NULL)) {
1292 		printf("ZFS: can't find vdev details\n");
1293 		return (ENOENT);
1294 	}
1295 
1296 	/* Wrong guid?! */
1297 	if (spa->spa_guid != pool_guid) {
1298 		nvlist_destroy(vdevs);
1299 		return (EINVAL);
1300 	}
1301 
1302 	spa->spa_root_vdev->v_nchildren = vdev_children;
1303 
1304 	rc = nvlist_find(vdevs, ZPOOL_CONFIG_CHILDREN, DATA_TYPE_NVLIST_ARRAY,
1305 	    &nkids, &kids, NULL);
1306 	nvlist_destroy(vdevs);
1307 
1308 	/*
1309 	 * MOS config has at least one child for root vdev.
1310 	 */
1311 	if (rc != 0)
1312 		return (rc);
1313 
1314 	for (int i = 0; i < nkids; i++) {
1315 		uint64_t guid;
1316 		vdev_t *vdev;
1317 
1318 		rc = nvlist_find(kids[i], ZPOOL_CONFIG_GUID, DATA_TYPE_UINT64,
1319 		    NULL, &guid, NULL);
1320 		if (rc != 0)
1321 			break;
1322 		vdev = vdev_find(guid);
1323 		/*
1324 		 * Top level vdev is missing, create it.
1325 		 */
1326 		if (vdev == NULL)
1327 			rc = vdev_from_nvlist(spa, guid, kids[i]);
1328 		else
1329 			rc = vdev_update_from_nvlist(guid, kids[i]);
1330 		if (rc != 0)
1331 			break;
1332 	}
1333 	if (kids != NULL) {
1334 		for (int i = 0; i < nkids; i++)
1335 			nvlist_destroy(kids[i]);
1336 		free(kids);
1337 	}
1338 
1339 	/*
1340 	 * Re-evaluate top-level vdev state.
1341 	 */
1342 	vdev_set_state(spa->spa_root_vdev);
1343 
1344 	return (rc);
1345 }
1346 
1347 static spa_t *
1348 spa_find_by_guid(uint64_t guid)
1349 {
1350 	spa_t *spa;
1351 
1352 	STAILQ_FOREACH(spa, &zfs_pools, spa_link)
1353 		if (spa->spa_guid == guid)
1354 			return (spa);
1355 
1356 	return (NULL);
1357 }
1358 
1359 static spa_t *
1360 spa_find_by_name(const char *name)
1361 {
1362 	spa_t *spa;
1363 
1364 	STAILQ_FOREACH(spa, &zfs_pools, spa_link)
1365 		if (strcmp(spa->spa_name, name) == 0)
1366 			return (spa);
1367 
1368 	return (NULL);
1369 }
1370 
1371 static spa_t *
1372 spa_create(uint64_t guid, const char *name)
1373 {
1374 	spa_t *spa;
1375 
1376 	if ((spa = calloc(1, sizeof(spa_t))) == NULL)
1377 		return (NULL);
1378 	if ((spa->spa_name = strdup(name)) == NULL) {
1379 		free(spa);
1380 		return (NULL);
1381 	}
1382 	spa->spa_uberblock = &spa->spa_uberblock_master;
1383 	spa->spa_mos = &spa->spa_mos_master;
1384 	spa->spa_guid = guid;
1385 	spa->spa_root_vdev = vdev_create(guid, NULL);
1386 	if (spa->spa_root_vdev == NULL) {
1387 		free(spa->spa_name);
1388 		free(spa);
1389 		return (NULL);
1390 	}
1391 	spa->spa_root_vdev->v_name = strdup("root");
1392 	STAILQ_INSERT_TAIL(&zfs_pools, spa, spa_link);
1393 
1394 	return (spa);
1395 }
1396 
1397 static const char *
1398 state_name(vdev_state_t state)
1399 {
1400 	static const char *names[] = {
1401 		"UNKNOWN",
1402 		"CLOSED",
1403 		"OFFLINE",
1404 		"REMOVED",
1405 		"CANT_OPEN",
1406 		"FAULTED",
1407 		"DEGRADED",
1408 		"ONLINE"
1409 	};
1410 	return (names[state]);
1411 }
1412 
1413 #ifdef BOOT2
1414 
1415 #define pager_printf printf
1416 
1417 #else
1418 
1419 static int
1420 pager_printf(const char *fmt, ...)
1421 {
1422 	char line[80];
1423 	va_list args;
1424 
1425 	va_start(args, fmt);
1426 	vsnprintf(line, sizeof(line), fmt, args);
1427 	va_end(args);
1428 	return (pager_output(line));
1429 }
1430 
1431 #endif
1432 
1433 #define	STATUS_FORMAT	"        %s %s\n"
1434 
1435 static int
1436 print_state(int indent, const char *name, vdev_state_t state)
1437 {
1438 	int i;
1439 	char buf[512];
1440 
1441 	buf[0] = 0;
1442 	for (i = 0; i < indent; i++)
1443 		strcat(buf, "  ");
1444 	strcat(buf, name);
1445 	return (pager_printf(STATUS_FORMAT, buf, state_name(state)));
1446 }
1447 
1448 static int
1449 vdev_status(vdev_t *vdev, int indent)
1450 {
1451 	vdev_t *kid;
1452 	int ret;
1453 
1454 	if (vdev->v_islog) {
1455 		(void) pager_output("        logs\n");
1456 		indent++;
1457 	}
1458 
1459 	ret = print_state(indent, vdev->v_name, vdev->v_state);
1460 	if (ret != 0)
1461 		return (ret);
1462 
1463 	STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
1464 		ret = vdev_status(kid, indent + 1);
1465 		if (ret != 0)
1466 			return (ret);
1467 	}
1468 	return (ret);
1469 }
1470 
1471 static int
1472 spa_status(spa_t *spa)
1473 {
1474 	static char bootfs[ZFS_MAXNAMELEN];
1475 	uint64_t rootid;
1476 	vdev_list_t *vlist;
1477 	vdev_t *vdev;
1478 	int good_kids, bad_kids, degraded_kids, ret;
1479 	vdev_state_t state;
1480 
1481 	ret = pager_printf("  pool: %s\n", spa->spa_name);
1482 	if (ret != 0)
1483 		return (ret);
1484 
1485 	if (zfs_get_root(spa, &rootid) == 0 &&
1486 	    zfs_rlookup(spa, rootid, bootfs) == 0) {
1487 		if (bootfs[0] == '\0')
1488 			ret = pager_printf("bootfs: %s\n", spa->spa_name);
1489 		else
1490 			ret = pager_printf("bootfs: %s/%s\n", spa->spa_name,
1491 			    bootfs);
1492 		if (ret != 0)
1493 			return (ret);
1494 	}
1495 	ret = pager_printf("config:\n\n");
1496 	if (ret != 0)
1497 		return (ret);
1498 	ret = pager_printf(STATUS_FORMAT, "NAME", "STATE");
1499 	if (ret != 0)
1500 		return (ret);
1501 
1502 	good_kids = 0;
1503 	degraded_kids = 0;
1504 	bad_kids = 0;
1505 	vlist = &spa->spa_root_vdev->v_children;
1506 	STAILQ_FOREACH(vdev, vlist, v_childlink) {
1507 		if (vdev->v_state == VDEV_STATE_HEALTHY)
1508 			good_kids++;
1509 		else if (vdev->v_state == VDEV_STATE_DEGRADED)
1510 			degraded_kids++;
1511 		else
1512 			bad_kids++;
1513 	}
1514 
1515 	state = VDEV_STATE_CLOSED;
1516 	if (good_kids > 0 && (degraded_kids + bad_kids) == 0)
1517 		state = VDEV_STATE_HEALTHY;
1518 	else if ((good_kids + degraded_kids) > 0)
1519 		state = VDEV_STATE_DEGRADED;
1520 
1521 	ret = print_state(0, spa->spa_name, state);
1522 	if (ret != 0)
1523 		return (ret);
1524 
1525 	STAILQ_FOREACH(vdev, vlist, v_childlink) {
1526 		ret = vdev_status(vdev, 1);
1527 		if (ret != 0)
1528 			return (ret);
1529 	}
1530 	return (ret);
1531 }
1532 
1533 static int
1534 spa_all_status(void)
1535 {
1536 	spa_t *spa;
1537 	int first = 1, ret = 0;
1538 
1539 	STAILQ_FOREACH(spa, &zfs_pools, spa_link) {
1540 		if (!first) {
1541 			ret = pager_printf("\n");
1542 			if (ret != 0)
1543 				return (ret);
1544 		}
1545 		first = 0;
1546 		ret = spa_status(spa);
1547 		if (ret != 0)
1548 			return (ret);
1549 	}
1550 	return (ret);
1551 }
1552 
1553 static uint64_t
1554 vdev_label_offset(uint64_t psize, int l, uint64_t offset)
1555 {
1556 	uint64_t label_offset;
1557 
1558 	if (l < VDEV_LABELS / 2)
1559 		label_offset = 0;
1560 	else
1561 		label_offset = psize - VDEV_LABELS * sizeof (vdev_label_t);
1562 
1563 	return (offset + l * sizeof (vdev_label_t) + label_offset);
1564 }
1565 
1566 static int
1567 vdev_uberblock_compare(const uberblock_t *ub1, const uberblock_t *ub2)
1568 {
1569 	unsigned int seq1 = 0;
1570 	unsigned int seq2 = 0;
1571 	int cmp = AVL_CMP(ub1->ub_txg, ub2->ub_txg);
1572 
1573 	if (cmp != 0)
1574 		return (cmp);
1575 
1576 	cmp = AVL_CMP(ub1->ub_timestamp, ub2->ub_timestamp);
1577 	if (cmp != 0)
1578 		return (cmp);
1579 
1580 	if (MMP_VALID(ub1) && MMP_SEQ_VALID(ub1))
1581 		seq1 = MMP_SEQ(ub1);
1582 
1583 	if (MMP_VALID(ub2) && MMP_SEQ_VALID(ub2))
1584 		seq2 = MMP_SEQ(ub2);
1585 
1586 	return (AVL_CMP(seq1, seq2));
1587 }
1588 
1589 static int
1590 uberblock_verify(uberblock_t *ub)
1591 {
1592 	if (ub->ub_magic == BSWAP_64((uint64_t)UBERBLOCK_MAGIC)) {
1593 		byteswap_uint64_array(ub, sizeof (uberblock_t));
1594 	}
1595 
1596 	if (ub->ub_magic != UBERBLOCK_MAGIC ||
1597 	    !SPA_VERSION_IS_SUPPORTED(ub->ub_version))
1598 		return (EINVAL);
1599 
1600 	return (0);
1601 }
1602 
1603 static int
1604 vdev_label_read(vdev_t *vd, int l, void *buf, uint64_t offset,
1605     size_t size)
1606 {
1607 	blkptr_t bp;
1608 	off_t off;
1609 
1610 	off = vdev_label_offset(vd->v_psize, l, offset);
1611 
1612 	BP_ZERO(&bp);
1613 	BP_SET_LSIZE(&bp, size);
1614 	BP_SET_PSIZE(&bp, size);
1615 	BP_SET_CHECKSUM(&bp, ZIO_CHECKSUM_LABEL);
1616 	BP_SET_COMPRESS(&bp, ZIO_COMPRESS_OFF);
1617 	DVA_SET_OFFSET(BP_IDENTITY(&bp), off);
1618 	ZIO_SET_CHECKSUM(&bp.blk_cksum, off, 0, 0, 0);
1619 
1620 	return (vdev_read_phys(vd, &bp, buf, off, size));
1621 }
1622 
1623 /*
1624  * We do need to be sure we write to correct location.
1625  * Our vdev label does consist of 4 fields:
1626  * pad1 (8k), reserved.
1627  * bootenv (8k), checksummed, previously reserved, may contian garbage.
1628  * vdev_phys (112k), checksummed
1629  * uberblock ring (128k), checksummed.
1630  *
1631  * Since bootenv area may contain garbage, we can not reliably read it, as
1632  * we can get checksum errors.
1633  * Next best thing is vdev_phys - it is just after bootenv. It still may
1634  * be corrupted, but in such case we will miss this one write.
1635  */
1636 static int
1637 vdev_label_write_validate(vdev_t *vd, int l, uint64_t offset)
1638 {
1639 	uint64_t off, o_phys;
1640 	void *buf;
1641 	size_t size = VDEV_PHYS_SIZE;
1642 	int rc;
1643 
1644 	o_phys = offsetof(vdev_label_t, vl_vdev_phys);
1645 	off = vdev_label_offset(vd->v_psize, l, o_phys);
1646 
1647 	/* off should be 8K from bootenv */
1648 	if (vdev_label_offset(vd->v_psize, l, offset) + VDEV_PAD_SIZE != off)
1649 		return (EINVAL);
1650 
1651 	buf = malloc(size);
1652 	if (buf == NULL)
1653 		return (ENOMEM);
1654 
1655 	/* Read vdev_phys */
1656 	rc = vdev_label_read(vd, l, buf, o_phys, size);
1657 	free(buf);
1658 	return (rc);
1659 }
1660 
1661 static int
1662 vdev_label_write(vdev_t *vd, int l, vdev_boot_envblock_t *be, uint64_t offset)
1663 {
1664 	zio_checksum_info_t *ci;
1665 	zio_cksum_t cksum;
1666 	off_t off;
1667 	size_t size = VDEV_PAD_SIZE;
1668 	int rc;
1669 
1670 	if (vd->v_phys_write == NULL)
1671 		return (ENOTSUP);
1672 
1673 	off = vdev_label_offset(vd->v_psize, l, offset);
1674 
1675 	rc = vdev_label_write_validate(vd, l, offset);
1676 	if (rc != 0) {
1677 		return (rc);
1678 	}
1679 
1680 	ci = &zio_checksum_table[ZIO_CHECKSUM_LABEL];
1681 	be->vbe_zbt.zec_magic = ZEC_MAGIC;
1682 	zio_checksum_label_verifier(&be->vbe_zbt.zec_cksum, off);
1683 	ci->ci_func[0](be, size, NULL, &cksum);
1684 	be->vbe_zbt.zec_cksum = cksum;
1685 
1686 	return (vdev_write_phys(vd, be, off, size));
1687 }
1688 
1689 static int
1690 vdev_write_bootenv_impl(vdev_t *vdev, vdev_boot_envblock_t *be)
1691 {
1692 	vdev_t *kid;
1693 	int rv = 0, rc;
1694 
1695 	STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
1696 		if (kid->v_state != VDEV_STATE_HEALTHY)
1697 			continue;
1698 		rc = vdev_write_bootenv_impl(kid, be);
1699 		if (rv == 0)
1700 			rv = rc;
1701 	}
1702 
1703 	/*
1704 	 * Non-leaf vdevs do not have v_phys_write.
1705 	 */
1706 	if (vdev->v_phys_write == NULL)
1707 		return (rv);
1708 
1709 	for (int l = 0; l < VDEV_LABELS; l++) {
1710 		rc = vdev_label_write(vdev, l, be,
1711 		    offsetof(vdev_label_t, vl_be));
1712 		if (rc != 0) {
1713 			printf("failed to write bootenv to %s label %d: %d\n",
1714 			    vdev->v_name ? vdev->v_name : "unknown", l, rc);
1715 			rv = rc;
1716 		}
1717 	}
1718 	return (rv);
1719 }
1720 
1721 int
1722 vdev_write_bootenv(vdev_t *vdev, nvlist_t *nvl)
1723 {
1724 	vdev_boot_envblock_t *be;
1725 	nvlist_t nv, *nvp;
1726 	uint64_t version;
1727 	int rv;
1728 
1729 	if (nvl->nv_size > sizeof(be->vbe_bootenv))
1730 		return (E2BIG);
1731 
1732 	version = VB_RAW;
1733 	nvp = vdev_read_bootenv(vdev);
1734 	if (nvp != NULL) {
1735 		nvlist_find(nvp, BOOTENV_VERSION, DATA_TYPE_UINT64, NULL,
1736 		    &version, NULL);
1737 		nvlist_destroy(nvp);
1738 	}
1739 
1740 	be = calloc(1, sizeof(*be));
1741 	if (be == NULL)
1742 		return (ENOMEM);
1743 
1744 	be->vbe_version = version;
1745 	switch (version) {
1746 	case VB_RAW:
1747 		/*
1748 		 * If there is no envmap, we will just wipe bootenv.
1749 		 */
1750 		nvlist_find(nvl, GRUB_ENVMAP, DATA_TYPE_STRING, NULL,
1751 		    be->vbe_bootenv, NULL);
1752 		rv = 0;
1753 		break;
1754 
1755 	case VB_NVLIST:
1756 		nv.nv_header = nvl->nv_header;
1757 		nv.nv_asize = nvl->nv_asize;
1758 		nv.nv_size = nvl->nv_size;
1759 
1760 		bcopy(&nv.nv_header, be->vbe_bootenv, sizeof(nv.nv_header));
1761 		nv.nv_data = be->vbe_bootenv + sizeof(nvs_header_t);
1762 		bcopy(nvl->nv_data, nv.nv_data, nv.nv_size);
1763 		rv = nvlist_export(&nv);
1764 		break;
1765 
1766 	default:
1767 		rv = EINVAL;
1768 		break;
1769 	}
1770 
1771 	if (rv == 0) {
1772 		be->vbe_version = htobe64(be->vbe_version);
1773 		rv = vdev_write_bootenv_impl(vdev, be);
1774 	}
1775 	free(be);
1776 	return (rv);
1777 }
1778 
1779 /*
1780  * Read the bootenv area from pool label, return the nvlist from it.
1781  * We return from first successful read.
1782  */
1783 nvlist_t *
1784 vdev_read_bootenv(vdev_t *vdev)
1785 {
1786 	vdev_t *kid;
1787 	nvlist_t *benv;
1788 	vdev_boot_envblock_t *be;
1789 	char *command;
1790 	bool ok;
1791 	int rv;
1792 
1793 	STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
1794 		if (kid->v_state != VDEV_STATE_HEALTHY)
1795 			continue;
1796 
1797 		benv = vdev_read_bootenv(kid);
1798 		if (benv != NULL)
1799 			return (benv);
1800 	}
1801 
1802 	be = malloc(sizeof (*be));
1803 	if (be == NULL)
1804 		return (NULL);
1805 
1806 	rv = 0;
1807 	for (int l = 0; l < VDEV_LABELS; l++) {
1808 		rv = vdev_label_read(vdev, l, be,
1809 		    offsetof(vdev_label_t, vl_be),
1810 		    sizeof (*be));
1811 		if (rv == 0)
1812 			break;
1813 	}
1814 	if (rv != 0) {
1815 		free(be);
1816 		return (NULL);
1817 	}
1818 
1819 	be->vbe_version = be64toh(be->vbe_version);
1820 	switch (be->vbe_version) {
1821 	case VB_RAW:
1822 		/*
1823 		 * we have textual data in vbe_bootenv, create nvlist
1824 		 * with key "envmap".
1825 		 */
1826 		benv = nvlist_create(NV_UNIQUE_NAME);
1827 		if (benv != NULL) {
1828 			if (*be->vbe_bootenv == '\0') {
1829 				nvlist_add_uint64(benv, BOOTENV_VERSION,
1830 				    VB_NVLIST);
1831 				break;
1832 			}
1833 			nvlist_add_uint64(benv, BOOTENV_VERSION, VB_RAW);
1834 			be->vbe_bootenv[sizeof (be->vbe_bootenv) - 1] = '\0';
1835 			nvlist_add_string(benv, GRUB_ENVMAP, be->vbe_bootenv);
1836 		}
1837 		break;
1838 
1839 	case VB_NVLIST:
1840 		benv = nvlist_import(be->vbe_bootenv, sizeof(be->vbe_bootenv));
1841 		break;
1842 
1843 	default:
1844 		command = (char *)be;
1845 		ok = false;
1846 
1847 		/* Check for legacy zfsbootcfg command string */
1848 		for (int i = 0; command[i] != '\0'; i++) {
1849 			if (iscntrl(command[i])) {
1850 				ok = false;
1851 				break;
1852 			} else {
1853 				ok = true;
1854 			}
1855 		}
1856 		benv = nvlist_create(NV_UNIQUE_NAME);
1857 		if (benv != NULL) {
1858 			if (ok)
1859 				nvlist_add_string(benv, FREEBSD_BOOTONCE,
1860 				    command);
1861 			else
1862 				nvlist_add_uint64(benv, BOOTENV_VERSION,
1863 				    VB_NVLIST);
1864 		}
1865 		break;
1866 	}
1867 	free(be);
1868 	return (benv);
1869 }
1870 
1871 static uint64_t
1872 vdev_get_label_asize(nvlist_t *nvl)
1873 {
1874 	nvlist_t *vdevs;
1875 	uint64_t asize;
1876 	const char *type;
1877 	int len;
1878 
1879 	asize = 0;
1880 	/* Get vdev tree */
1881 	if (nvlist_find(nvl, ZPOOL_CONFIG_VDEV_TREE, DATA_TYPE_NVLIST,
1882 	    NULL, &vdevs, NULL) != 0)
1883 		return (asize);
1884 
1885 	/*
1886 	 * Get vdev type. We will calculate asize for raidz, mirror and disk.
1887 	 * For raidz, the asize is raw size of all children.
1888 	 */
1889 	if (nvlist_find(vdevs, ZPOOL_CONFIG_TYPE, DATA_TYPE_STRING,
1890 	    NULL, &type, &len) != 0)
1891 		goto done;
1892 
1893 	if (memcmp(type, VDEV_TYPE_MIRROR, len) != 0 &&
1894 	    memcmp(type, VDEV_TYPE_DISK, len) != 0 &&
1895 	    memcmp(type, VDEV_TYPE_RAIDZ, len) != 0)
1896 		goto done;
1897 
1898 	if (nvlist_find(vdevs, ZPOOL_CONFIG_ASIZE, DATA_TYPE_UINT64,
1899 	    NULL, &asize, NULL) != 0)
1900 		goto done;
1901 
1902 	if (memcmp(type, VDEV_TYPE_RAIDZ, len) == 0) {
1903 		nvlist_t **kids;
1904 		int nkids;
1905 
1906 		if (nvlist_find(vdevs, ZPOOL_CONFIG_CHILDREN,
1907 		    DATA_TYPE_NVLIST_ARRAY, &nkids, &kids, NULL) != 0) {
1908 			asize = 0;
1909 			goto done;
1910 		}
1911 
1912 		asize /= nkids;
1913 		for (int i = 0; i < nkids; i++)
1914 			nvlist_destroy(kids[i]);
1915 		free(kids);
1916 	}
1917 
1918 	asize += VDEV_LABEL_START_SIZE + VDEV_LABEL_END_SIZE;
1919 done:
1920 	nvlist_destroy(vdevs);
1921 	return (asize);
1922 }
1923 
1924 static nvlist_t *
1925 vdev_label_read_config(vdev_t *vd, uint64_t txg)
1926 {
1927 	vdev_phys_t *label;
1928 	uint64_t best_txg = 0;
1929 	uint64_t label_txg = 0;
1930 	uint64_t asize;
1931 	nvlist_t *nvl = NULL, *tmp;
1932 	int error;
1933 
1934 	label = malloc(sizeof (vdev_phys_t));
1935 	if (label == NULL)
1936 		return (NULL);
1937 
1938 	for (int l = 0; l < VDEV_LABELS; l++) {
1939 		if (vdev_label_read(vd, l, label,
1940 		    offsetof(vdev_label_t, vl_vdev_phys),
1941 		    sizeof (vdev_phys_t)))
1942 			continue;
1943 
1944 		tmp = nvlist_import(label->vp_nvlist,
1945 		    sizeof(label->vp_nvlist));
1946 		if (tmp == NULL)
1947 			continue;
1948 
1949 		error = nvlist_find(tmp, ZPOOL_CONFIG_POOL_TXG,
1950 		    DATA_TYPE_UINT64, NULL, &label_txg, NULL);
1951 		if (error != 0 || label_txg == 0) {
1952 			nvlist_destroy(nvl);
1953 			nvl = tmp;
1954 			goto done;
1955 		}
1956 
1957 		if (label_txg <= txg && label_txg > best_txg) {
1958 			best_txg = label_txg;
1959 			nvlist_destroy(nvl);
1960 			nvl = tmp;
1961 			tmp = NULL;
1962 
1963 			/*
1964 			 * Use asize from pool config. We need this
1965 			 * because we can get bad value from BIOS.
1966 			 */
1967 			asize = vdev_get_label_asize(nvl);
1968 			if (asize != 0) {
1969 				vd->v_psize = asize;
1970 			}
1971 		}
1972 		nvlist_destroy(tmp);
1973 	}
1974 
1975 	if (best_txg == 0) {
1976 		nvlist_destroy(nvl);
1977 		nvl = NULL;
1978 	}
1979 done:
1980 	free(label);
1981 	return (nvl);
1982 }
1983 
1984 static void
1985 vdev_uberblock_load(vdev_t *vd, uberblock_t *ub)
1986 {
1987 	uberblock_t *buf;
1988 
1989 	buf = malloc(VDEV_UBERBLOCK_SIZE(vd));
1990 	if (buf == NULL)
1991 		return;
1992 
1993 	for (int l = 0; l < VDEV_LABELS; l++) {
1994 		for (int n = 0; n < VDEV_UBERBLOCK_COUNT(vd); n++) {
1995 			if (vdev_label_read(vd, l, buf,
1996 			    VDEV_UBERBLOCK_OFFSET(vd, n),
1997 			    VDEV_UBERBLOCK_SIZE(vd)))
1998 				continue;
1999 			if (uberblock_verify(buf) != 0)
2000 				continue;
2001 
2002 			if (vdev_uberblock_compare(buf, ub) > 0)
2003 				*ub = *buf;
2004 		}
2005 	}
2006 	free(buf);
2007 }
2008 
2009 static int
2010 vdev_probe(vdev_phys_read_t *_read, vdev_phys_write_t *_write, void *priv,
2011     spa_t **spap)
2012 {
2013 	vdev_t vtmp;
2014 	spa_t *spa;
2015 	vdev_t *vdev;
2016 	nvlist_t *nvl;
2017 	uint64_t val;
2018 	uint64_t guid, vdev_children;
2019 	uint64_t pool_txg, pool_guid;
2020 	const char *pool_name;
2021 	int rc, namelen;
2022 
2023 	/*
2024 	 * Load the vdev label and figure out which
2025 	 * uberblock is most current.
2026 	 */
2027 	memset(&vtmp, 0, sizeof(vtmp));
2028 	vtmp.v_phys_read = _read;
2029 	vtmp.v_phys_write = _write;
2030 	vtmp.v_priv = priv;
2031 	vtmp.v_psize = P2ALIGN(ldi_get_size(priv),
2032 	    (uint64_t)sizeof (vdev_label_t));
2033 
2034 	/* Test for minimum device size. */
2035 	if (vtmp.v_psize < SPA_MINDEVSIZE)
2036 		return (EIO);
2037 
2038 	nvl = vdev_label_read_config(&vtmp, UINT64_MAX);
2039 	if (nvl == NULL)
2040 		return (EIO);
2041 
2042 	if (nvlist_find(nvl, ZPOOL_CONFIG_VERSION, DATA_TYPE_UINT64,
2043 	    NULL, &val, NULL) != 0) {
2044 		nvlist_destroy(nvl);
2045 		return (EIO);
2046 	}
2047 
2048 	if (!SPA_VERSION_IS_SUPPORTED(val)) {
2049 		printf("ZFS: unsupported ZFS version %u (should be %u)\n",
2050 		    (unsigned)val, (unsigned)SPA_VERSION);
2051 		nvlist_destroy(nvl);
2052 		return (EIO);
2053 	}
2054 
2055 	/* Check ZFS features for read */
2056 	rc = nvlist_check_features_for_read(nvl);
2057 	if (rc != 0) {
2058 		nvlist_destroy(nvl);
2059 		return (EIO);
2060 	}
2061 
2062 	if (nvlist_find(nvl, ZPOOL_CONFIG_POOL_STATE, DATA_TYPE_UINT64,
2063 	    NULL, &val, NULL) != 0) {
2064 		nvlist_destroy(nvl);
2065 		return (EIO);
2066 	}
2067 
2068 	if (val == POOL_STATE_DESTROYED) {
2069 		/* We don't boot only from destroyed pools. */
2070 		nvlist_destroy(nvl);
2071 		return (EIO);
2072 	}
2073 
2074 	if (nvlist_find(nvl, ZPOOL_CONFIG_POOL_TXG, DATA_TYPE_UINT64,
2075 	    NULL, &pool_txg, NULL) != 0 ||
2076 	    nvlist_find(nvl, ZPOOL_CONFIG_POOL_GUID, DATA_TYPE_UINT64,
2077 	    NULL, &pool_guid, NULL) != 0 ||
2078 	    nvlist_find(nvl, ZPOOL_CONFIG_POOL_NAME, DATA_TYPE_STRING,
2079 	    NULL, &pool_name, &namelen) != 0) {
2080 		/*
2081 		 * Cache and spare devices end up here - just ignore
2082 		 * them.
2083 		 */
2084 		nvlist_destroy(nvl);
2085 		return (EIO);
2086 	}
2087 
2088 	/*
2089 	 * Create the pool if this is the first time we've seen it.
2090 	 */
2091 	spa = spa_find_by_guid(pool_guid);
2092 	if (spa == NULL) {
2093 		char *name;
2094 
2095 		nvlist_find(nvl, ZPOOL_CONFIG_VDEV_CHILDREN,
2096 		    DATA_TYPE_UINT64, NULL, &vdev_children, NULL);
2097 		name = malloc(namelen + 1);
2098 		if (name == NULL) {
2099 			nvlist_destroy(nvl);
2100 			return (ENOMEM);
2101 		}
2102 		bcopy(pool_name, name, namelen);
2103 		name[namelen] = '\0';
2104 		spa = spa_create(pool_guid, name);
2105 		free(name);
2106 		if (spa == NULL) {
2107 			nvlist_destroy(nvl);
2108 			return (ENOMEM);
2109 		}
2110 		spa->spa_root_vdev->v_nchildren = vdev_children;
2111 	}
2112 	if (pool_txg > spa->spa_txg)
2113 		spa->spa_txg = pool_txg;
2114 
2115 	/*
2116 	 * Get the vdev tree and create our in-core copy of it.
2117 	 * If we already have a vdev with this guid, this must
2118 	 * be some kind of alias (overlapping slices, dangerously dedicated
2119 	 * disks etc).
2120 	 */
2121 	if (nvlist_find(nvl, ZPOOL_CONFIG_GUID, DATA_TYPE_UINT64,
2122 	    NULL, &guid, NULL) != 0) {
2123 		nvlist_destroy(nvl);
2124 		return (EIO);
2125 	}
2126 	vdev = vdev_find(guid);
2127 	/* Has this vdev already been inited? */
2128 	if (vdev && vdev->v_phys_read) {
2129 		nvlist_destroy(nvl);
2130 		return (EIO);
2131 	}
2132 
2133 	rc = vdev_init_from_label(spa, nvl);
2134 	nvlist_destroy(nvl);
2135 	if (rc != 0)
2136 		return (rc);
2137 
2138 	/*
2139 	 * We should already have created an incomplete vdev for this
2140 	 * vdev. Find it and initialise it with our read proc.
2141 	 */
2142 	vdev = vdev_find(guid);
2143 	if (vdev != NULL) {
2144 		vdev->v_phys_read = _read;
2145 		vdev->v_phys_write = _write;
2146 		vdev->v_priv = priv;
2147 		vdev->v_psize = vtmp.v_psize;
2148 		/*
2149 		 * If no other state is set, mark vdev healthy.
2150 		 */
2151 		if (vdev->v_state == VDEV_STATE_UNKNOWN)
2152 			vdev->v_state = VDEV_STATE_HEALTHY;
2153 	} else {
2154 		printf("ZFS: inconsistent nvlist contents\n");
2155 		return (EIO);
2156 	}
2157 
2158 	if (vdev->v_islog)
2159 		spa->spa_with_log = vdev->v_islog;
2160 
2161 	/*
2162 	 * Re-evaluate top-level vdev state.
2163 	 */
2164 	vdev_set_state(vdev->v_top);
2165 
2166 	/*
2167 	 * Ok, we are happy with the pool so far. Lets find
2168 	 * the best uberblock and then we can actually access
2169 	 * the contents of the pool.
2170 	 */
2171 	vdev_uberblock_load(vdev, spa->spa_uberblock);
2172 
2173 	if (spap != NULL)
2174 		*spap = spa;
2175 	return (0);
2176 }
2177 
2178 static int
2179 ilog2(int n)
2180 {
2181 	int v;
2182 
2183 	for (v = 0; v < 32; v++)
2184 		if (n == (1 << v))
2185 			return (v);
2186 	return (-1);
2187 }
2188 
2189 static int
2190 zio_read_gang(const spa_t *spa, const blkptr_t *bp, void *buf)
2191 {
2192 	blkptr_t gbh_bp;
2193 	zio_gbh_phys_t zio_gb;
2194 	char *pbuf;
2195 	int i;
2196 
2197 	/* Artificial BP for gang block header. */
2198 	gbh_bp = *bp;
2199 	BP_SET_PSIZE(&gbh_bp, SPA_GANGBLOCKSIZE);
2200 	BP_SET_LSIZE(&gbh_bp, SPA_GANGBLOCKSIZE);
2201 	BP_SET_CHECKSUM(&gbh_bp, ZIO_CHECKSUM_GANG_HEADER);
2202 	BP_SET_COMPRESS(&gbh_bp, ZIO_COMPRESS_OFF);
2203 	for (i = 0; i < SPA_DVAS_PER_BP; i++)
2204 		DVA_SET_GANG(&gbh_bp.blk_dva[i], 0);
2205 
2206 	/* Read gang header block using the artificial BP. */
2207 	if (zio_read(spa, &gbh_bp, &zio_gb))
2208 		return (EIO);
2209 
2210 	pbuf = buf;
2211 	for (i = 0; i < SPA_GBH_NBLKPTRS; i++) {
2212 		blkptr_t *gbp = &zio_gb.zg_blkptr[i];
2213 
2214 		if (BP_IS_HOLE(gbp))
2215 			continue;
2216 		if (zio_read(spa, gbp, pbuf))
2217 			return (EIO);
2218 		pbuf += BP_GET_PSIZE(gbp);
2219 	}
2220 
2221 	if (zio_checksum_verify(spa, bp, buf))
2222 		return (EIO);
2223 	return (0);
2224 }
2225 
2226 static int
2227 zio_read(const spa_t *spa, const blkptr_t *bp, void *buf)
2228 {
2229 	int cpfunc = BP_GET_COMPRESS(bp);
2230 	uint64_t align, size;
2231 	void *pbuf;
2232 	int i, error;
2233 
2234 	/*
2235 	 * Process data embedded in block pointer
2236 	 */
2237 	if (BP_IS_EMBEDDED(bp)) {
2238 		ASSERT(BPE_GET_ETYPE(bp) == BP_EMBEDDED_TYPE_DATA);
2239 
2240 		size = BPE_GET_PSIZE(bp);
2241 		ASSERT(size <= BPE_PAYLOAD_SIZE);
2242 
2243 		if (cpfunc != ZIO_COMPRESS_OFF)
2244 			pbuf = malloc(size);
2245 		else
2246 			pbuf = buf;
2247 
2248 		if (pbuf == NULL)
2249 			return (ENOMEM);
2250 
2251 		decode_embedded_bp_compressed(bp, pbuf);
2252 		error = 0;
2253 
2254 		if (cpfunc != ZIO_COMPRESS_OFF) {
2255 			error = zio_decompress_data(cpfunc, pbuf,
2256 			    size, buf, BP_GET_LSIZE(bp));
2257 			free(pbuf);
2258 		}
2259 		if (error != 0)
2260 			printf("ZFS: i/o error - unable to decompress "
2261 			    "block pointer data, error %d\n", error);
2262 		return (error);
2263 	}
2264 
2265 	error = EIO;
2266 
2267 	for (i = 0; i < SPA_DVAS_PER_BP; i++) {
2268 		const dva_t *dva = &bp->blk_dva[i];
2269 		vdev_t *vdev;
2270 		vdev_list_t *vlist;
2271 		uint64_t vdevid;
2272 		off_t offset;
2273 
2274 		if (!dva->dva_word[0] && !dva->dva_word[1])
2275 			continue;
2276 
2277 		vdevid = DVA_GET_VDEV(dva);
2278 		offset = DVA_GET_OFFSET(dva);
2279 		vlist = &spa->spa_root_vdev->v_children;
2280 		STAILQ_FOREACH(vdev, vlist, v_childlink) {
2281 			if (vdev->v_id == vdevid)
2282 				break;
2283 		}
2284 		if (!vdev || !vdev->v_read)
2285 			continue;
2286 
2287 		size = BP_GET_PSIZE(bp);
2288 		if (vdev->v_read == vdev_raidz_read) {
2289 			align = 1ULL << vdev->v_ashift;
2290 			if (P2PHASE(size, align) != 0)
2291 				size = P2ROUNDUP(size, align);
2292 		}
2293 		if (size != BP_GET_PSIZE(bp) || cpfunc != ZIO_COMPRESS_OFF)
2294 			pbuf = malloc(size);
2295 		else
2296 			pbuf = buf;
2297 
2298 		if (pbuf == NULL) {
2299 			error = ENOMEM;
2300 			break;
2301 		}
2302 
2303 		if (DVA_GET_GANG(dva))
2304 			error = zio_read_gang(spa, bp, pbuf);
2305 		else
2306 			error = vdev->v_read(vdev, bp, pbuf, offset, size);
2307 		if (error == 0) {
2308 			if (cpfunc != ZIO_COMPRESS_OFF)
2309 				error = zio_decompress_data(cpfunc, pbuf,
2310 				    BP_GET_PSIZE(bp), buf, BP_GET_LSIZE(bp));
2311 			else if (size != BP_GET_PSIZE(bp))
2312 				bcopy(pbuf, buf, BP_GET_PSIZE(bp));
2313 		} else {
2314 			printf("zio_read error: %d\n", error);
2315 		}
2316 		if (buf != pbuf)
2317 			free(pbuf);
2318 		if (error == 0)
2319 			break;
2320 	}
2321 	if (error != 0)
2322 		printf("ZFS: i/o error - all block copies unavailable\n");
2323 
2324 	return (error);
2325 }
2326 
2327 static int
2328 dnode_read(const spa_t *spa, const dnode_phys_t *dnode, off_t offset,
2329     void *buf, size_t buflen)
2330 {
2331 	int ibshift = dnode->dn_indblkshift - SPA_BLKPTRSHIFT;
2332 	int bsize = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
2333 	int nlevels = dnode->dn_nlevels;
2334 	int i, rc;
2335 
2336 	if (bsize > SPA_MAXBLOCKSIZE) {
2337 		printf("ZFS: I/O error - blocks larger than %llu are not "
2338 		    "supported\n", SPA_MAXBLOCKSIZE);
2339 		return (EIO);
2340 	}
2341 
2342 	/*
2343 	 * Handle odd block sizes, mirrors dmu_read_impl().  Data can't exist
2344 	 * past the first block, so we'll clip the read to the portion of the
2345 	 * buffer within bsize and zero out the remainder.
2346 	 */
2347 	if (dnode->dn_maxblkid == 0) {
2348 		size_t newbuflen;
2349 
2350 		newbuflen = offset > bsize ? 0 : MIN(buflen, bsize - offset);
2351 		bzero((char *)buf + newbuflen, buflen - newbuflen);
2352 		buflen = newbuflen;
2353 	}
2354 
2355 	/*
2356 	 * Note: bsize may not be a power of two here so we need to do an
2357 	 * actual divide rather than a bitshift.
2358 	 */
2359 	while (buflen > 0) {
2360 		uint64_t bn = offset / bsize;
2361 		int boff = offset % bsize;
2362 		int ibn;
2363 		const blkptr_t *indbp;
2364 		blkptr_t bp;
2365 
2366 		if (bn > dnode->dn_maxblkid)
2367 			return (EIO);
2368 
2369 		if (dnode == dnode_cache_obj && bn == dnode_cache_bn)
2370 			goto cached;
2371 
2372 		indbp = dnode->dn_blkptr;
2373 		for (i = 0; i < nlevels; i++) {
2374 			/*
2375 			 * Copy the bp from the indirect array so that
2376 			 * we can re-use the scratch buffer for multi-level
2377 			 * objects.
2378 			 */
2379 			ibn = bn >> ((nlevels - i - 1) * ibshift);
2380 			ibn &= ((1 << ibshift) - 1);
2381 			bp = indbp[ibn];
2382 			if (BP_IS_HOLE(&bp)) {
2383 				memset(dnode_cache_buf, 0, bsize);
2384 				break;
2385 			}
2386 			rc = zio_read(spa, &bp, dnode_cache_buf);
2387 			if (rc)
2388 				return (rc);
2389 			indbp = (const blkptr_t *) dnode_cache_buf;
2390 		}
2391 		dnode_cache_obj = dnode;
2392 		dnode_cache_bn = bn;
2393 	cached:
2394 
2395 		/*
2396 		 * The buffer contains our data block. Copy what we
2397 		 * need from it and loop.
2398 		 */
2399 		i = bsize - boff;
2400 		if (i > buflen) i = buflen;
2401 		memcpy(buf, &dnode_cache_buf[boff], i);
2402 		buf = ((char *)buf) + i;
2403 		offset += i;
2404 		buflen -= i;
2405 	}
2406 
2407 	return (0);
2408 }
2409 
2410 /*
2411  * Lookup a value in a microzap directory.
2412  */
2413 static int
2414 mzap_lookup(const mzap_phys_t *mz, size_t size, const char *name,
2415     uint64_t *value)
2416 {
2417 	const mzap_ent_phys_t *mze;
2418 	int chunks, i;
2419 
2420 	/*
2421 	 * Microzap objects use exactly one block. Read the whole
2422 	 * thing.
2423 	 */
2424 	chunks = size / MZAP_ENT_LEN - 1;
2425 	for (i = 0; i < chunks; i++) {
2426 		mze = &mz->mz_chunk[i];
2427 		if (strcmp(mze->mze_name, name) == 0) {
2428 			*value = mze->mze_value;
2429 			return (0);
2430 		}
2431 	}
2432 
2433 	return (ENOENT);
2434 }
2435 
2436 /*
2437  * Compare a name with a zap leaf entry. Return non-zero if the name
2438  * matches.
2439  */
2440 static int
2441 fzap_name_equal(const zap_leaf_t *zl, const zap_leaf_chunk_t *zc,
2442     const char *name)
2443 {
2444 	size_t namelen;
2445 	const zap_leaf_chunk_t *nc;
2446 	const char *p;
2447 
2448 	namelen = zc->l_entry.le_name_numints;
2449 
2450 	nc = &ZAP_LEAF_CHUNK(zl, zc->l_entry.le_name_chunk);
2451 	p = name;
2452 	while (namelen > 0) {
2453 		size_t len;
2454 
2455 		len = namelen;
2456 		if (len > ZAP_LEAF_ARRAY_BYTES)
2457 			len = ZAP_LEAF_ARRAY_BYTES;
2458 		if (memcmp(p, nc->l_array.la_array, len))
2459 			return (0);
2460 		p += len;
2461 		namelen -= len;
2462 		nc = &ZAP_LEAF_CHUNK(zl, nc->l_array.la_next);
2463 	}
2464 
2465 	return (1);
2466 }
2467 
2468 /*
2469  * Extract a uint64_t value from a zap leaf entry.
2470  */
2471 static uint64_t
2472 fzap_leaf_value(const zap_leaf_t *zl, const zap_leaf_chunk_t *zc)
2473 {
2474 	const zap_leaf_chunk_t *vc;
2475 	int i;
2476 	uint64_t value;
2477 	const uint8_t *p;
2478 
2479 	vc = &ZAP_LEAF_CHUNK(zl, zc->l_entry.le_value_chunk);
2480 	for (i = 0, value = 0, p = vc->l_array.la_array; i < 8; i++) {
2481 		value = (value << 8) | p[i];
2482 	}
2483 
2484 	return (value);
2485 }
2486 
2487 static void
2488 stv(int len, void *addr, uint64_t value)
2489 {
2490 	switch (len) {
2491 	case 1:
2492 		*(uint8_t *)addr = value;
2493 		return;
2494 	case 2:
2495 		*(uint16_t *)addr = value;
2496 		return;
2497 	case 4:
2498 		*(uint32_t *)addr = value;
2499 		return;
2500 	case 8:
2501 		*(uint64_t *)addr = value;
2502 		return;
2503 	}
2504 }
2505 
2506 /*
2507  * Extract a array from a zap leaf entry.
2508  */
2509 static void
2510 fzap_leaf_array(const zap_leaf_t *zl, const zap_leaf_chunk_t *zc,
2511     uint64_t integer_size, uint64_t num_integers, void *buf)
2512 {
2513 	uint64_t array_int_len = zc->l_entry.le_value_intlen;
2514 	uint64_t value = 0;
2515 	uint64_t *u64 = buf;
2516 	char *p = buf;
2517 	int len = MIN(zc->l_entry.le_value_numints, num_integers);
2518 	int chunk = zc->l_entry.le_value_chunk;
2519 	int byten = 0;
2520 
2521 	if (integer_size == 8 && len == 1) {
2522 		*u64 = fzap_leaf_value(zl, zc);
2523 		return;
2524 	}
2525 
2526 	while (len > 0) {
2527 		struct zap_leaf_array *la = &ZAP_LEAF_CHUNK(zl, chunk).l_array;
2528 		int i;
2529 
2530 		ASSERT3U(chunk, <, ZAP_LEAF_NUMCHUNKS(zl));
2531 		for (i = 0; i < ZAP_LEAF_ARRAY_BYTES && len > 0; i++) {
2532 			value = (value << 8) | la->la_array[i];
2533 			byten++;
2534 			if (byten == array_int_len) {
2535 				stv(integer_size, p, value);
2536 				byten = 0;
2537 				len--;
2538 				if (len == 0)
2539 					return;
2540 				p += integer_size;
2541 			}
2542 		}
2543 		chunk = la->la_next;
2544 	}
2545 }
2546 
2547 static int
2548 fzap_check_size(uint64_t integer_size, uint64_t num_integers)
2549 {
2550 
2551 	switch (integer_size) {
2552 	case 1:
2553 	case 2:
2554 	case 4:
2555 	case 8:
2556 		break;
2557 	default:
2558 		return (EINVAL);
2559 	}
2560 
2561 	if (integer_size * num_integers > ZAP_MAXVALUELEN)
2562 		return (E2BIG);
2563 
2564 	return (0);
2565 }
2566 
2567 static void
2568 zap_leaf_free(zap_leaf_t *leaf)
2569 {
2570 	free(leaf->l_phys);
2571 	free(leaf);
2572 }
2573 
2574 static int
2575 zap_get_leaf_byblk(fat_zap_t *zap, uint64_t blk, zap_leaf_t **lp)
2576 {
2577 	int bs = FZAP_BLOCK_SHIFT(zap);
2578 	int err;
2579 
2580 	*lp = malloc(sizeof(**lp));
2581 	if (*lp == NULL)
2582 		return (ENOMEM);
2583 
2584 	(*lp)->l_bs = bs;
2585 	(*lp)->l_phys = malloc(1 << bs);
2586 
2587 	if ((*lp)->l_phys == NULL) {
2588 		free(*lp);
2589 		return (ENOMEM);
2590 	}
2591 	err = dnode_read(zap->zap_spa, zap->zap_dnode, blk << bs, (*lp)->l_phys,
2592 	    1 << bs);
2593 	if (err != 0) {
2594 		zap_leaf_free(*lp);
2595 	}
2596 	return (err);
2597 }
2598 
2599 static int
2600 zap_table_load(fat_zap_t *zap, zap_table_phys_t *tbl, uint64_t idx,
2601     uint64_t *valp)
2602 {
2603 	int bs = FZAP_BLOCK_SHIFT(zap);
2604 	uint64_t blk = idx >> (bs - 3);
2605 	uint64_t off = idx & ((1 << (bs - 3)) - 1);
2606 	uint64_t *buf;
2607 	int rc;
2608 
2609 	buf = malloc(1 << zap->zap_block_shift);
2610 	if (buf == NULL)
2611 		return (ENOMEM);
2612 	rc = dnode_read(zap->zap_spa, zap->zap_dnode, (tbl->zt_blk + blk) << bs,
2613 	    buf, 1 << zap->zap_block_shift);
2614 	if (rc == 0)
2615 		*valp = buf[off];
2616 	free(buf);
2617 	return (rc);
2618 }
2619 
2620 static int
2621 zap_idx_to_blk(fat_zap_t *zap, uint64_t idx, uint64_t *valp)
2622 {
2623 	if (zap->zap_phys->zap_ptrtbl.zt_numblks == 0) {
2624 		*valp = ZAP_EMBEDDED_PTRTBL_ENT(zap, idx);
2625 		return (0);
2626 	} else {
2627 		return (zap_table_load(zap, &zap->zap_phys->zap_ptrtbl,
2628 		    idx, valp));
2629 	}
2630 }
2631 
2632 #define	ZAP_HASH_IDX(hash, n)	(((n) == 0) ? 0 : ((hash) >> (64 - (n))))
2633 static int
2634 zap_deref_leaf(fat_zap_t *zap, uint64_t h, zap_leaf_t **lp)
2635 {
2636 	uint64_t idx, blk;
2637 	int err;
2638 
2639 	idx = ZAP_HASH_IDX(h, zap->zap_phys->zap_ptrtbl.zt_shift);
2640 	err = zap_idx_to_blk(zap, idx, &blk);
2641 	if (err != 0)
2642 		return (err);
2643 	return (zap_get_leaf_byblk(zap, blk, lp));
2644 }
2645 
2646 #define	CHAIN_END	0xffff	/* end of the chunk chain */
2647 #define	LEAF_HASH(l, h) \
2648 	((ZAP_LEAF_HASH_NUMENTRIES(l)-1) & \
2649 	((h) >> \
2650 	(64 - ZAP_LEAF_HASH_SHIFT(l) - (l)->l_phys->l_hdr.lh_prefix_len)))
2651 #define	LEAF_HASH_ENTPTR(l, h)	(&(l)->l_phys->l_hash[LEAF_HASH(l, h)])
2652 
2653 static int
2654 zap_leaf_lookup(zap_leaf_t *zl, uint64_t hash, const char *name,
2655     uint64_t integer_size, uint64_t num_integers, void *value)
2656 {
2657 	int rc;
2658 	uint16_t *chunkp;
2659 	struct zap_leaf_entry *le;
2660 
2661 	/*
2662 	 * Make sure this chunk matches our hash.
2663 	 */
2664 	if (zl->l_phys->l_hdr.lh_prefix_len > 0 &&
2665 	    zl->l_phys->l_hdr.lh_prefix !=
2666 	    hash >> (64 - zl->l_phys->l_hdr.lh_prefix_len))
2667 		return (EIO);
2668 
2669 	rc = ENOENT;
2670 	for (chunkp = LEAF_HASH_ENTPTR(zl, hash);
2671 	    *chunkp != CHAIN_END; chunkp = &le->le_next) {
2672 		zap_leaf_chunk_t *zc;
2673 		uint16_t chunk = *chunkp;
2674 
2675 		le = ZAP_LEAF_ENTRY(zl, chunk);
2676 		if (le->le_hash != hash)
2677 			continue;
2678 		zc = &ZAP_LEAF_CHUNK(zl, chunk);
2679 		if (fzap_name_equal(zl, zc, name)) {
2680 			if (zc->l_entry.le_value_intlen > integer_size) {
2681 				rc = EINVAL;
2682 			} else {
2683 				fzap_leaf_array(zl, zc, integer_size,
2684 				    num_integers, value);
2685 				rc = 0;
2686 			}
2687 			break;
2688 		}
2689 	}
2690 	return (rc);
2691 }
2692 
2693 /*
2694  * Lookup a value in a fatzap directory.
2695  */
2696 static int
2697 fzap_lookup(const spa_t *spa, const dnode_phys_t *dnode, zap_phys_t *zh,
2698     const char *name, uint64_t integer_size, uint64_t num_integers,
2699     void *value)
2700 {
2701 	int bsize = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
2702 	fat_zap_t z;
2703 	zap_leaf_t *zl;
2704 	uint64_t hash;
2705 	int rc;
2706 
2707 	if (zh->zap_magic != ZAP_MAGIC)
2708 		return (EIO);
2709 
2710 	if ((rc = fzap_check_size(integer_size, num_integers)) != 0) {
2711 		return (rc);
2712 	}
2713 
2714 	z.zap_block_shift = ilog2(bsize);
2715 	z.zap_phys = zh;
2716 	z.zap_spa = spa;
2717 	z.zap_dnode = dnode;
2718 
2719 	hash = zap_hash(zh->zap_salt, name);
2720 	rc = zap_deref_leaf(&z, hash, &zl);
2721 	if (rc != 0)
2722 		return (rc);
2723 
2724 	rc = zap_leaf_lookup(zl, hash, name, integer_size, num_integers, value);
2725 
2726 	zap_leaf_free(zl);
2727 	return (rc);
2728 }
2729 
2730 /*
2731  * Lookup a name in a zap object and return its value as a uint64_t.
2732  */
2733 static int
2734 zap_lookup(const spa_t *spa, const dnode_phys_t *dnode, const char *name,
2735     uint64_t integer_size, uint64_t num_integers, void *value)
2736 {
2737 	int rc;
2738 	zap_phys_t *zap;
2739 	size_t size = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
2740 
2741 	zap = malloc(size);
2742 	if (zap == NULL)
2743 		return (ENOMEM);
2744 
2745 	rc = dnode_read(spa, dnode, 0, zap, size);
2746 	if (rc)
2747 		goto done;
2748 
2749 	switch (zap->zap_block_type) {
2750 	case ZBT_MICRO:
2751 		rc = mzap_lookup((const mzap_phys_t *)zap, size, name, value);
2752 		break;
2753 	case ZBT_HEADER:
2754 		rc = fzap_lookup(spa, dnode, zap, name, integer_size,
2755 		    num_integers, value);
2756 		break;
2757 	default:
2758 		printf("ZFS: invalid zap_type=%" PRIx64 "\n",
2759 		    zap->zap_block_type);
2760 		rc = EIO;
2761 	}
2762 done:
2763 	free(zap);
2764 	return (rc);
2765 }
2766 
2767 /*
2768  * List a microzap directory.
2769  */
2770 static int
2771 mzap_list(const mzap_phys_t *mz, size_t size,
2772     int (*callback)(const char *, uint64_t))
2773 {
2774 	const mzap_ent_phys_t *mze;
2775 	int chunks, i, rc;
2776 
2777 	/*
2778 	 * Microzap objects use exactly one block. Read the whole
2779 	 * thing.
2780 	 */
2781 	rc = 0;
2782 	chunks = size / MZAP_ENT_LEN - 1;
2783 	for (i = 0; i < chunks; i++) {
2784 		mze = &mz->mz_chunk[i];
2785 		if (mze->mze_name[0]) {
2786 			rc = callback(mze->mze_name, mze->mze_value);
2787 			if (rc != 0)
2788 				break;
2789 		}
2790 	}
2791 
2792 	return (rc);
2793 }
2794 
2795 /*
2796  * List a fatzap directory.
2797  */
2798 static int
2799 fzap_list(const spa_t *spa, const dnode_phys_t *dnode, zap_phys_t *zh,
2800     int (*callback)(const char *, uint64_t))
2801 {
2802 	int bsize = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
2803 	fat_zap_t z;
2804 	uint64_t i;
2805 	int j, rc;
2806 
2807 	if (zh->zap_magic != ZAP_MAGIC)
2808 		return (EIO);
2809 
2810 	z.zap_block_shift = ilog2(bsize);
2811 	z.zap_phys = zh;
2812 
2813 	/*
2814 	 * This assumes that the leaf blocks start at block 1. The
2815 	 * documentation isn't exactly clear on this.
2816 	 */
2817 	zap_leaf_t zl;
2818 	zl.l_bs = z.zap_block_shift;
2819 	zl.l_phys = malloc(bsize);
2820 	if (zl.l_phys == NULL)
2821 		return (ENOMEM);
2822 
2823 	for (i = 0; i < zh->zap_num_leafs; i++) {
2824 		off_t off = ((off_t)(i + 1)) << zl.l_bs;
2825 		char name[256], *p;
2826 		uint64_t value;
2827 
2828 		if (dnode_read(spa, dnode, off, zl.l_phys, bsize)) {
2829 			free(zl.l_phys);
2830 			return (EIO);
2831 		}
2832 
2833 		for (j = 0; j < ZAP_LEAF_NUMCHUNKS(&zl); j++) {
2834 			zap_leaf_chunk_t *zc, *nc;
2835 			int namelen;
2836 
2837 			zc = &ZAP_LEAF_CHUNK(&zl, j);
2838 			if (zc->l_entry.le_type != ZAP_CHUNK_ENTRY)
2839 				continue;
2840 			namelen = zc->l_entry.le_name_numints;
2841 			if (namelen > sizeof(name))
2842 				namelen = sizeof(name);
2843 
2844 			/*
2845 			 * Paste the name back together.
2846 			 */
2847 			nc = &ZAP_LEAF_CHUNK(&zl, zc->l_entry.le_name_chunk);
2848 			p = name;
2849 			while (namelen > 0) {
2850 				int len;
2851 				len = namelen;
2852 				if (len > ZAP_LEAF_ARRAY_BYTES)
2853 					len = ZAP_LEAF_ARRAY_BYTES;
2854 				memcpy(p, nc->l_array.la_array, len);
2855 				p += len;
2856 				namelen -= len;
2857 				nc = &ZAP_LEAF_CHUNK(&zl, nc->l_array.la_next);
2858 			}
2859 
2860 			/*
2861 			 * Assume the first eight bytes of the value are
2862 			 * a uint64_t.
2863 			 */
2864 			value = fzap_leaf_value(&zl, zc);
2865 
2866 			/* printf("%s 0x%jx\n", name, (uintmax_t)value); */
2867 			rc = callback((const char *)name, value);
2868 			if (rc != 0) {
2869 				free(zl.l_phys);
2870 				return (rc);
2871 			}
2872 		}
2873 	}
2874 
2875 	free(zl.l_phys);
2876 	return (0);
2877 }
2878 
2879 static int zfs_printf(const char *name, uint64_t value __unused)
2880 {
2881 
2882 	printf("%s\n", name);
2883 
2884 	return (0);
2885 }
2886 
2887 /*
2888  * List a zap directory.
2889  */
2890 static int
2891 zap_list(const spa_t *spa, const dnode_phys_t *dnode)
2892 {
2893 	zap_phys_t *zap;
2894 	size_t size = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
2895 	int rc;
2896 
2897 	zap = malloc(size);
2898 	if (zap == NULL)
2899 		return (ENOMEM);
2900 
2901 	rc = dnode_read(spa, dnode, 0, zap, size);
2902 	if (rc == 0) {
2903 		if (zap->zap_block_type == ZBT_MICRO)
2904 			rc = mzap_list((const mzap_phys_t *)zap, size,
2905 			    zfs_printf);
2906 		else
2907 			rc = fzap_list(spa, dnode, zap, zfs_printf);
2908 	}
2909 	free(zap);
2910 	return (rc);
2911 }
2912 
2913 static int
2914 objset_get_dnode(const spa_t *spa, const objset_phys_t *os, uint64_t objnum,
2915     dnode_phys_t *dnode)
2916 {
2917 	off_t offset;
2918 
2919 	offset = objnum * sizeof(dnode_phys_t);
2920 	return dnode_read(spa, &os->os_meta_dnode, offset,
2921 		dnode, sizeof(dnode_phys_t));
2922 }
2923 
2924 /*
2925  * Lookup a name in a microzap directory.
2926  */
2927 static int
2928 mzap_rlookup(const mzap_phys_t *mz, size_t size, char *name, uint64_t value)
2929 {
2930 	const mzap_ent_phys_t *mze;
2931 	int chunks, i;
2932 
2933 	/*
2934 	 * Microzap objects use exactly one block. Read the whole
2935 	 * thing.
2936 	 */
2937 	chunks = size / MZAP_ENT_LEN - 1;
2938 	for (i = 0; i < chunks; i++) {
2939 		mze = &mz->mz_chunk[i];
2940 		if (value == mze->mze_value) {
2941 			strcpy(name, mze->mze_name);
2942 			return (0);
2943 		}
2944 	}
2945 
2946 	return (ENOENT);
2947 }
2948 
2949 static void
2950 fzap_name_copy(const zap_leaf_t *zl, const zap_leaf_chunk_t *zc, char *name)
2951 {
2952 	size_t namelen;
2953 	const zap_leaf_chunk_t *nc;
2954 	char *p;
2955 
2956 	namelen = zc->l_entry.le_name_numints;
2957 
2958 	nc = &ZAP_LEAF_CHUNK(zl, zc->l_entry.le_name_chunk);
2959 	p = name;
2960 	while (namelen > 0) {
2961 		size_t len;
2962 		len = namelen;
2963 		if (len > ZAP_LEAF_ARRAY_BYTES)
2964 			len = ZAP_LEAF_ARRAY_BYTES;
2965 		memcpy(p, nc->l_array.la_array, len);
2966 		p += len;
2967 		namelen -= len;
2968 		nc = &ZAP_LEAF_CHUNK(zl, nc->l_array.la_next);
2969 	}
2970 
2971 	*p = '\0';
2972 }
2973 
2974 static int
2975 fzap_rlookup(const spa_t *spa, const dnode_phys_t *dnode, zap_phys_t *zh,
2976     char *name, uint64_t value)
2977 {
2978 	int bsize = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
2979 	fat_zap_t z;
2980 	uint64_t i;
2981 	int j, rc;
2982 
2983 	if (zh->zap_magic != ZAP_MAGIC)
2984 		return (EIO);
2985 
2986 	z.zap_block_shift = ilog2(bsize);
2987 	z.zap_phys = zh;
2988 
2989 	/*
2990 	 * This assumes that the leaf blocks start at block 1. The
2991 	 * documentation isn't exactly clear on this.
2992 	 */
2993 	zap_leaf_t zl;
2994 	zl.l_bs = z.zap_block_shift;
2995 	zl.l_phys = malloc(bsize);
2996 	if (zl.l_phys == NULL)
2997 		return (ENOMEM);
2998 
2999 	for (i = 0; i < zh->zap_num_leafs; i++) {
3000 		off_t off = ((off_t)(i + 1)) << zl.l_bs;
3001 
3002 		rc = dnode_read(spa, dnode, off, zl.l_phys, bsize);
3003 		if (rc != 0)
3004 			goto done;
3005 
3006 		for (j = 0; j < ZAP_LEAF_NUMCHUNKS(&zl); j++) {
3007 			zap_leaf_chunk_t *zc;
3008 
3009 			zc = &ZAP_LEAF_CHUNK(&zl, j);
3010 			if (zc->l_entry.le_type != ZAP_CHUNK_ENTRY)
3011 				continue;
3012 			if (zc->l_entry.le_value_intlen != 8 ||
3013 			    zc->l_entry.le_value_numints != 1)
3014 				continue;
3015 
3016 			if (fzap_leaf_value(&zl, zc) == value) {
3017 				fzap_name_copy(&zl, zc, name);
3018 				goto done;
3019 			}
3020 		}
3021 	}
3022 
3023 	rc = ENOENT;
3024 done:
3025 	free(zl.l_phys);
3026 	return (rc);
3027 }
3028 
3029 static int
3030 zap_rlookup(const spa_t *spa, const dnode_phys_t *dnode, char *name,
3031     uint64_t value)
3032 {
3033 	zap_phys_t *zap;
3034 	size_t size = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
3035 	int rc;
3036 
3037 	zap = malloc(size);
3038 	if (zap == NULL)
3039 		return (ENOMEM);
3040 
3041 	rc = dnode_read(spa, dnode, 0, zap, size);
3042 	if (rc == 0) {
3043 		if (zap->zap_block_type == ZBT_MICRO)
3044 			rc = mzap_rlookup((const mzap_phys_t *)zap, size,
3045 			    name, value);
3046 		else
3047 			rc = fzap_rlookup(spa, dnode, zap, name, value);
3048 	}
3049 	free(zap);
3050 	return (rc);
3051 }
3052 
3053 static int
3054 zfs_rlookup(const spa_t *spa, uint64_t objnum, char *result)
3055 {
3056 	char name[256];
3057 	char component[256];
3058 	uint64_t dir_obj, parent_obj, child_dir_zapobj;
3059 	dnode_phys_t child_dir_zap, snapnames_zap, dataset, dir, parent;
3060 	dsl_dir_phys_t *dd;
3061 	dsl_dataset_phys_t *ds;
3062 	char *p;
3063 	int len;
3064 	boolean_t issnap = B_FALSE;
3065 
3066 	p = &name[sizeof(name) - 1];
3067 	*p = '\0';
3068 
3069 	if (objset_get_dnode(spa, spa->spa_mos, objnum, &dataset)) {
3070 		printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
3071 		return (EIO);
3072 	}
3073 	ds = (dsl_dataset_phys_t *)&dataset.dn_bonus;
3074 	dir_obj = ds->ds_dir_obj;
3075 	if (ds->ds_snapnames_zapobj == 0)
3076 		issnap = B_TRUE;
3077 
3078 	for (;;) {
3079 		if (objset_get_dnode(spa, spa->spa_mos, dir_obj, &dir) != 0)
3080 			return (EIO);
3081 		dd = (dsl_dir_phys_t *)&dir.dn_bonus;
3082 
3083 		/* Actual loop condition. */
3084 		parent_obj = dd->dd_parent_obj;
3085 		if (parent_obj == 0)
3086 			break;
3087 
3088 		if (objset_get_dnode(spa, spa->spa_mos, parent_obj,
3089 		    &parent) != 0)
3090 			return (EIO);
3091 		dd = (dsl_dir_phys_t *)&parent.dn_bonus;
3092 		if (issnap == B_TRUE) {
3093 			/*
3094 			 * The dataset we are looking up is a snapshot
3095 			 * the dir_obj is the parent already, we don't want
3096 			 * the grandparent just yet. Reset to the parent.
3097 			 */
3098 			dd = (dsl_dir_phys_t *)&dir.dn_bonus;
3099 			/* Lookup the dataset to get the snapname ZAP */
3100 			if (objset_get_dnode(spa, spa->spa_mos,
3101 			    dd->dd_head_dataset_obj, &dataset))
3102 				return (EIO);
3103 			ds = (dsl_dataset_phys_t *)&dataset.dn_bonus;
3104 			if (objset_get_dnode(spa, spa->spa_mos,
3105 			    ds->ds_snapnames_zapobj, &snapnames_zap) != 0)
3106 				return (EIO);
3107 			/* Get the name of the snapshot */
3108 			if (zap_rlookup(spa, &snapnames_zap, component,
3109 			    objnum) != 0)
3110 				return (EIO);
3111 			len = strlen(component);
3112 			p -= len;
3113 			memcpy(p, component, len);
3114 			--p;
3115 			*p = '@';
3116 			issnap = B_FALSE;
3117 			continue;
3118 		}
3119 
3120 		child_dir_zapobj = dd->dd_child_dir_zapobj;
3121 		if (objset_get_dnode(spa, spa->spa_mos, child_dir_zapobj,
3122 		    &child_dir_zap) != 0)
3123 			return (EIO);
3124 		if (zap_rlookup(spa, &child_dir_zap, component, dir_obj) != 0)
3125 			return (EIO);
3126 
3127 		len = strlen(component);
3128 		p -= len;
3129 		memcpy(p, component, len);
3130 		--p;
3131 		*p = '/';
3132 
3133 		/* Actual loop iteration. */
3134 		dir_obj = parent_obj;
3135 	}
3136 
3137 	if (*p != '\0')
3138 		++p;
3139 	strcpy(result, p);
3140 
3141 	return (0);
3142 }
3143 
3144 static int
3145 zfs_lookup_dataset(const spa_t *spa, const char *name, uint64_t *objnum)
3146 {
3147 	char element[256];
3148 	uint64_t dir_obj, child_dir_zapobj;
3149 	dnode_phys_t child_dir_zap, snapnames_zap, dir, dataset;
3150 	dsl_dir_phys_t *dd;
3151 	dsl_dataset_phys_t *ds;
3152 	const char *p, *q;
3153 	boolean_t issnap = B_FALSE;
3154 
3155 	if (objset_get_dnode(spa, spa->spa_mos,
3156 	    DMU_POOL_DIRECTORY_OBJECT, &dir))
3157 		return (EIO);
3158 	if (zap_lookup(spa, &dir, DMU_POOL_ROOT_DATASET, sizeof (dir_obj),
3159 	    1, &dir_obj))
3160 		return (EIO);
3161 
3162 	p = name;
3163 	for (;;) {
3164 		if (objset_get_dnode(spa, spa->spa_mos, dir_obj, &dir))
3165 			return (EIO);
3166 		dd = (dsl_dir_phys_t *)&dir.dn_bonus;
3167 
3168 		while (*p == '/')
3169 			p++;
3170 		/* Actual loop condition #1. */
3171 		if (*p == '\0')
3172 			break;
3173 
3174 		q = strchr(p, '/');
3175 		if (q) {
3176 			memcpy(element, p, q - p);
3177 			element[q - p] = '\0';
3178 			p = q + 1;
3179 		} else {
3180 			strcpy(element, p);
3181 			p += strlen(p);
3182 		}
3183 
3184 		if (issnap == B_TRUE) {
3185 		        if (objset_get_dnode(spa, spa->spa_mos,
3186 			    dd->dd_head_dataset_obj, &dataset))
3187 		                return (EIO);
3188 			ds = (dsl_dataset_phys_t *)&dataset.dn_bonus;
3189 			if (objset_get_dnode(spa, spa->spa_mos,
3190 			    ds->ds_snapnames_zapobj, &snapnames_zap) != 0)
3191 				return (EIO);
3192 			/* Actual loop condition #2. */
3193 			if (zap_lookup(spa, &snapnames_zap, element,
3194 			    sizeof (dir_obj), 1, &dir_obj) != 0)
3195 				return (ENOENT);
3196 			*objnum = dir_obj;
3197 			return (0);
3198 		} else if ((q = strchr(element, '@')) != NULL) {
3199 			issnap = B_TRUE;
3200 			element[q - element] = '\0';
3201 			p = q + 1;
3202 		}
3203 		child_dir_zapobj = dd->dd_child_dir_zapobj;
3204 		if (objset_get_dnode(spa, spa->spa_mos, child_dir_zapobj,
3205 		    &child_dir_zap) != 0)
3206 			return (EIO);
3207 
3208 		/* Actual loop condition #2. */
3209 		if (zap_lookup(spa, &child_dir_zap, element, sizeof (dir_obj),
3210 		    1, &dir_obj) != 0)
3211 			return (ENOENT);
3212 	}
3213 
3214 	*objnum = dd->dd_head_dataset_obj;
3215 	return (0);
3216 }
3217 
3218 #ifndef BOOT2
3219 static int
3220 zfs_list_dataset(const spa_t *spa, uint64_t objnum/*, int pos, char *entry*/)
3221 {
3222 	uint64_t dir_obj, child_dir_zapobj;
3223 	dnode_phys_t child_dir_zap, dir, dataset;
3224 	dsl_dataset_phys_t *ds;
3225 	dsl_dir_phys_t *dd;
3226 
3227 	if (objset_get_dnode(spa, spa->spa_mos, objnum, &dataset)) {
3228 		printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
3229 		return (EIO);
3230 	}
3231 	ds = (dsl_dataset_phys_t *)&dataset.dn_bonus;
3232 	dir_obj = ds->ds_dir_obj;
3233 
3234 	if (objset_get_dnode(spa, spa->spa_mos, dir_obj, &dir)) {
3235 		printf("ZFS: can't find dirobj %ju\n", (uintmax_t)dir_obj);
3236 		return (EIO);
3237 	}
3238 	dd = (dsl_dir_phys_t *)&dir.dn_bonus;
3239 
3240 	child_dir_zapobj = dd->dd_child_dir_zapobj;
3241 	if (objset_get_dnode(spa, spa->spa_mos, child_dir_zapobj,
3242 	    &child_dir_zap) != 0) {
3243 		printf("ZFS: can't find child zap %ju\n", (uintmax_t)dir_obj);
3244 		return (EIO);
3245 	}
3246 
3247 	return (zap_list(spa, &child_dir_zap) != 0);
3248 }
3249 
3250 int
3251 zfs_callback_dataset(const spa_t *spa, uint64_t objnum,
3252     int (*callback)(const char *, uint64_t))
3253 {
3254 	uint64_t dir_obj, child_dir_zapobj;
3255 	dnode_phys_t child_dir_zap, dir, dataset;
3256 	dsl_dataset_phys_t *ds;
3257 	dsl_dir_phys_t *dd;
3258 	zap_phys_t *zap;
3259 	size_t size;
3260 	int err;
3261 
3262 	err = objset_get_dnode(spa, spa->spa_mos, objnum, &dataset);
3263 	if (err != 0) {
3264 		printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
3265 		return (err);
3266 	}
3267 	ds = (dsl_dataset_phys_t *)&dataset.dn_bonus;
3268 	dir_obj = ds->ds_dir_obj;
3269 
3270 	err = objset_get_dnode(spa, spa->spa_mos, dir_obj, &dir);
3271 	if (err != 0) {
3272 		printf("ZFS: can't find dirobj %ju\n", (uintmax_t)dir_obj);
3273 		return (err);
3274 	}
3275 	dd = (dsl_dir_phys_t *)&dir.dn_bonus;
3276 
3277 	child_dir_zapobj = dd->dd_child_dir_zapobj;
3278 	err = objset_get_dnode(spa, spa->spa_mos, child_dir_zapobj,
3279 	    &child_dir_zap);
3280 	if (err != 0) {
3281 		printf("ZFS: can't find child zap %ju\n", (uintmax_t)dir_obj);
3282 		return (err);
3283 	}
3284 
3285 	size = child_dir_zap.dn_datablkszsec << SPA_MINBLOCKSHIFT;
3286 	zap = malloc(size);
3287 	if (zap != NULL) {
3288 		err = dnode_read(spa, &child_dir_zap, 0, zap, size);
3289 		if (err != 0)
3290 			goto done;
3291 
3292 		if (zap->zap_block_type == ZBT_MICRO)
3293 			err = mzap_list((const mzap_phys_t *)zap, size,
3294 			    callback);
3295 		else
3296 			err = fzap_list(spa, &child_dir_zap, zap, callback);
3297 	} else {
3298 		err = ENOMEM;
3299 	}
3300 done:
3301 	free(zap);
3302 	return (err);
3303 }
3304 #endif
3305 
3306 /*
3307  * Find the object set given the object number of its dataset object
3308  * and return its details in *objset
3309  */
3310 static int
3311 zfs_mount_dataset(const spa_t *spa, uint64_t objnum, objset_phys_t *objset)
3312 {
3313 	dnode_phys_t dataset;
3314 	dsl_dataset_phys_t *ds;
3315 
3316 	if (objset_get_dnode(spa, spa->spa_mos, objnum, &dataset)) {
3317 		printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
3318 		return (EIO);
3319 	}
3320 
3321 	ds = (dsl_dataset_phys_t *)&dataset.dn_bonus;
3322 	if (zio_read(spa, &ds->ds_bp, objset)) {
3323 		printf("ZFS: can't read object set for dataset %ju\n",
3324 		    (uintmax_t)objnum);
3325 		return (EIO);
3326 	}
3327 
3328 	return (0);
3329 }
3330 
3331 /*
3332  * Find the object set pointed to by the BOOTFS property or the root
3333  * dataset if there is none and return its details in *objset
3334  */
3335 static int
3336 zfs_get_root(const spa_t *spa, uint64_t *objid)
3337 {
3338 	dnode_phys_t dir, propdir;
3339 	uint64_t props, bootfs, root;
3340 
3341 	*objid = 0;
3342 
3343 	/*
3344 	 * Start with the MOS directory object.
3345 	 */
3346 	if (objset_get_dnode(spa, spa->spa_mos,
3347 	    DMU_POOL_DIRECTORY_OBJECT, &dir)) {
3348 		printf("ZFS: can't read MOS object directory\n");
3349 		return (EIO);
3350 	}
3351 
3352 	/*
3353 	 * Lookup the pool_props and see if we can find a bootfs.
3354 	 */
3355 	if (zap_lookup(spa, &dir, DMU_POOL_PROPS,
3356 	    sizeof(props), 1, &props) == 0 &&
3357 	    objset_get_dnode(spa, spa->spa_mos, props, &propdir) == 0 &&
3358 	    zap_lookup(spa, &propdir, "bootfs",
3359 	    sizeof(bootfs), 1, &bootfs) == 0 && bootfs != 0) {
3360 		*objid = bootfs;
3361 		return (0);
3362 	}
3363 	/*
3364 	 * Lookup the root dataset directory
3365 	 */
3366 	if (zap_lookup(spa, &dir, DMU_POOL_ROOT_DATASET,
3367 	    sizeof(root), 1, &root) ||
3368 	    objset_get_dnode(spa, spa->spa_mos, root, &dir)) {
3369 		printf("ZFS: can't find root dsl_dir\n");
3370 		return (EIO);
3371 	}
3372 
3373 	/*
3374 	 * Use the information from the dataset directory's bonus buffer
3375 	 * to find the dataset object and from that the object set itself.
3376 	 */
3377 	dsl_dir_phys_t *dd = (dsl_dir_phys_t *)&dir.dn_bonus;
3378 	*objid = dd->dd_head_dataset_obj;
3379 	return (0);
3380 }
3381 
3382 static int
3383 zfs_mount_impl(const spa_t *spa, uint64_t rootobj, struct zfsmount *mount)
3384 {
3385 
3386 	mount->spa = spa;
3387 
3388 	/*
3389 	 * Find the root object set if not explicitly provided
3390 	 */
3391 	if (rootobj == 0 && zfs_get_root(spa, &rootobj)) {
3392 		printf("ZFS: can't find root filesystem\n");
3393 		return (EIO);
3394 	}
3395 
3396 	if (zfs_mount_dataset(spa, rootobj, &mount->objset)) {
3397 		printf("ZFS: can't open root filesystem\n");
3398 		return (EIO);
3399 	}
3400 
3401 	mount->rootobj = rootobj;
3402 
3403 	return (0);
3404 }
3405 
3406 /*
3407  * callback function for feature name checks.
3408  */
3409 static int
3410 check_feature(const char *name, uint64_t value)
3411 {
3412 	int i;
3413 
3414 	if (value == 0)
3415 		return (0);
3416 	if (name[0] == '\0')
3417 		return (0);
3418 
3419 	for (i = 0; features_for_read[i] != NULL; i++) {
3420 		if (strcmp(name, features_for_read[i]) == 0)
3421 			return (0);
3422 	}
3423 	printf("ZFS: unsupported feature: %s\n", name);
3424 	return (EIO);
3425 }
3426 
3427 /*
3428  * Checks whether the MOS features that are active are supported.
3429  */
3430 static int
3431 check_mos_features(const spa_t *spa)
3432 {
3433 	dnode_phys_t dir;
3434 	zap_phys_t *zap;
3435 	uint64_t objnum;
3436 	size_t size;
3437 	int rc;
3438 
3439 	if ((rc = objset_get_dnode(spa, spa->spa_mos, DMU_OT_OBJECT_DIRECTORY,
3440 	    &dir)) != 0)
3441 		return (rc);
3442 	if ((rc = zap_lookup(spa, &dir, DMU_POOL_FEATURES_FOR_READ,
3443 	    sizeof (objnum), 1, &objnum)) != 0) {
3444 		/*
3445 		 * It is older pool without features. As we have already
3446 		 * tested the label, just return without raising the error.
3447 		 */
3448 		return (0);
3449 	}
3450 
3451 	if ((rc = objset_get_dnode(spa, spa->spa_mos, objnum, &dir)) != 0)
3452 		return (rc);
3453 
3454 	if (dir.dn_type != DMU_OTN_ZAP_METADATA)
3455 		return (EIO);
3456 
3457 	size = dir.dn_datablkszsec << SPA_MINBLOCKSHIFT;
3458 	zap = malloc(size);
3459 	if (zap == NULL)
3460 		return (ENOMEM);
3461 
3462 	if (dnode_read(spa, &dir, 0, zap, size)) {
3463 		free(zap);
3464 		return (EIO);
3465 	}
3466 
3467 	if (zap->zap_block_type == ZBT_MICRO)
3468 		rc = mzap_list((const mzap_phys_t *)zap, size, check_feature);
3469 	else
3470 		rc = fzap_list(spa, &dir, zap, check_feature);
3471 
3472 	free(zap);
3473 	return (rc);
3474 }
3475 
3476 static int
3477 load_nvlist(spa_t *spa, uint64_t obj, nvlist_t **value)
3478 {
3479 	dnode_phys_t dir;
3480 	size_t size;
3481 	int rc;
3482 	char *nv;
3483 
3484 	*value = NULL;
3485 	if ((rc = objset_get_dnode(spa, spa->spa_mos, obj, &dir)) != 0)
3486 		return (rc);
3487 	if (dir.dn_type != DMU_OT_PACKED_NVLIST &&
3488 	    dir.dn_bonustype != DMU_OT_PACKED_NVLIST_SIZE) {
3489 		return (EIO);
3490 	}
3491 
3492 	if (dir.dn_bonuslen != sizeof (uint64_t))
3493 		return (EIO);
3494 
3495 	size = *(uint64_t *)DN_BONUS(&dir);
3496 	nv = malloc(size);
3497 	if (nv == NULL)
3498 		return (ENOMEM);
3499 
3500 	rc = dnode_read(spa, &dir, 0, nv, size);
3501 	if (rc != 0) {
3502 		free(nv);
3503 		nv = NULL;
3504 		return (rc);
3505 	}
3506 	*value = nvlist_import(nv, size);
3507 	free(nv);
3508 	return (rc);
3509 }
3510 
3511 static int
3512 zfs_spa_init(spa_t *spa)
3513 {
3514 	struct uberblock checkpoint;
3515 	dnode_phys_t dir;
3516 	uint64_t config_object;
3517 	nvlist_t *nvlist;
3518 	int rc;
3519 
3520 	if (zio_read(spa, &spa->spa_uberblock->ub_rootbp, spa->spa_mos)) {
3521 		printf("ZFS: can't read MOS of pool %s\n", spa->spa_name);
3522 		return (EIO);
3523 	}
3524 	if (spa->spa_mos->os_type != DMU_OST_META) {
3525 		printf("ZFS: corrupted MOS of pool %s\n", spa->spa_name);
3526 		return (EIO);
3527 	}
3528 
3529 	if (objset_get_dnode(spa, &spa->spa_mos_master,
3530 	    DMU_POOL_DIRECTORY_OBJECT, &dir)) {
3531 		printf("ZFS: failed to read pool %s directory object\n",
3532 		    spa->spa_name);
3533 		return (EIO);
3534 	}
3535 	/* this is allowed to fail, older pools do not have salt */
3536 	rc = zap_lookup(spa, &dir, DMU_POOL_CHECKSUM_SALT, 1,
3537 	    sizeof (spa->spa_cksum_salt.zcs_bytes),
3538 	    spa->spa_cksum_salt.zcs_bytes);
3539 
3540 	rc = check_mos_features(spa);
3541 	if (rc != 0) {
3542 		printf("ZFS: pool %s is not supported\n", spa->spa_name);
3543 		return (rc);
3544 	}
3545 
3546 	rc = zap_lookup(spa, &dir, DMU_POOL_CONFIG,
3547 	    sizeof (config_object), 1, &config_object);
3548 	if (rc != 0) {
3549 		printf("ZFS: can not read MOS %s\n", DMU_POOL_CONFIG);
3550 		return (EIO);
3551 	}
3552 	rc = load_nvlist(spa, config_object, &nvlist);
3553 	if (rc != 0)
3554 		return (rc);
3555 
3556 	rc = zap_lookup(spa, &dir, DMU_POOL_ZPOOL_CHECKPOINT,
3557 	    sizeof(uint64_t), sizeof(checkpoint) / sizeof(uint64_t),
3558 	    &checkpoint);
3559 	if (rc == 0 && checkpoint.ub_checkpoint_txg != 0) {
3560 		memcpy(&spa->spa_uberblock_checkpoint, &checkpoint,
3561 		    sizeof(checkpoint));
3562 		if (zio_read(spa, &spa->spa_uberblock_checkpoint.ub_rootbp,
3563 		    &spa->spa_mos_checkpoint)) {
3564 			printf("ZFS: can not read checkpoint data.\n");
3565 			return (EIO);
3566 		}
3567 	}
3568 
3569 	/*
3570 	 * Update vdevs from MOS config. Note, we do skip encoding bytes
3571 	 * here. See also vdev_label_read_config().
3572 	 */
3573 	rc = vdev_init_from_nvlist(spa, nvlist);
3574 	nvlist_destroy(nvlist);
3575 	return (rc);
3576 }
3577 
3578 static int
3579 zfs_dnode_stat(const spa_t *spa, dnode_phys_t *dn, struct stat *sb)
3580 {
3581 
3582 	if (dn->dn_bonustype != DMU_OT_SA) {
3583 		znode_phys_t *zp = (znode_phys_t *)dn->dn_bonus;
3584 
3585 		sb->st_mode = zp->zp_mode;
3586 		sb->st_uid = zp->zp_uid;
3587 		sb->st_gid = zp->zp_gid;
3588 		sb->st_size = zp->zp_size;
3589 	} else {
3590 		sa_hdr_phys_t *sahdrp;
3591 		int hdrsize;
3592 		size_t size = 0;
3593 		void *buf = NULL;
3594 
3595 		if (dn->dn_bonuslen != 0)
3596 			sahdrp = (sa_hdr_phys_t *)DN_BONUS(dn);
3597 		else {
3598 			if ((dn->dn_flags & DNODE_FLAG_SPILL_BLKPTR) != 0) {
3599 				blkptr_t *bp = DN_SPILL_BLKPTR(dn);
3600 				int error;
3601 
3602 				size = BP_GET_LSIZE(bp);
3603 				buf = malloc(size);
3604 				if (buf == NULL)
3605 					error = ENOMEM;
3606 				else
3607 					error = zio_read(spa, bp, buf);
3608 
3609 				if (error != 0) {
3610 					free(buf);
3611 					return (error);
3612 				}
3613 				sahdrp = buf;
3614 			} else {
3615 				return (EIO);
3616 			}
3617 		}
3618 		hdrsize = SA_HDR_SIZE(sahdrp);
3619 		sb->st_mode = *(uint64_t *)((char *)sahdrp + hdrsize +
3620 		    SA_MODE_OFFSET);
3621 		sb->st_uid = *(uint64_t *)((char *)sahdrp + hdrsize +
3622 		    SA_UID_OFFSET);
3623 		sb->st_gid = *(uint64_t *)((char *)sahdrp + hdrsize +
3624 		    SA_GID_OFFSET);
3625 		sb->st_size = *(uint64_t *)((char *)sahdrp + hdrsize +
3626 		    SA_SIZE_OFFSET);
3627 		free(buf);
3628 	}
3629 
3630 	return (0);
3631 }
3632 
3633 static int
3634 zfs_dnode_readlink(const spa_t *spa, dnode_phys_t *dn, char *path, size_t psize)
3635 {
3636 	int rc = 0;
3637 
3638 	if (dn->dn_bonustype == DMU_OT_SA) {
3639 		sa_hdr_phys_t *sahdrp = NULL;
3640 		size_t size = 0;
3641 		void *buf = NULL;
3642 		int hdrsize;
3643 		char *p;
3644 
3645 		if (dn->dn_bonuslen != 0) {
3646 			sahdrp = (sa_hdr_phys_t *)DN_BONUS(dn);
3647 		} else {
3648 			blkptr_t *bp;
3649 
3650 			if ((dn->dn_flags & DNODE_FLAG_SPILL_BLKPTR) == 0)
3651 				return (EIO);
3652 			bp = DN_SPILL_BLKPTR(dn);
3653 
3654 			size = BP_GET_LSIZE(bp);
3655 			buf = malloc(size);
3656 			if (buf == NULL)
3657 				rc = ENOMEM;
3658 			else
3659 				rc = zio_read(spa, bp, buf);
3660 			if (rc != 0) {
3661 				free(buf);
3662 				return (rc);
3663 			}
3664 			sahdrp = buf;
3665 		}
3666 		hdrsize = SA_HDR_SIZE(sahdrp);
3667 		p = (char *)((uintptr_t)sahdrp + hdrsize + SA_SYMLINK_OFFSET);
3668 		memcpy(path, p, psize);
3669 		free(buf);
3670 		return (0);
3671 	}
3672 	/*
3673 	 * Second test is purely to silence bogus compiler
3674 	 * warning about accessing past the end of dn_bonus.
3675 	 */
3676 	if (psize + sizeof(znode_phys_t) <= dn->dn_bonuslen &&
3677 	    sizeof(znode_phys_t) <= sizeof(dn->dn_bonus)) {
3678 		memcpy(path, &dn->dn_bonus[sizeof(znode_phys_t)], psize);
3679 	} else {
3680 		rc = dnode_read(spa, dn, 0, path, psize);
3681 	}
3682 	return (rc);
3683 }
3684 
3685 struct obj_list {
3686 	uint64_t		objnum;
3687 	STAILQ_ENTRY(obj_list)	entry;
3688 };
3689 
3690 /*
3691  * Lookup a file and return its dnode.
3692  */
3693 static int
3694 zfs_lookup(const struct zfsmount *mount, const char *upath, dnode_phys_t *dnode)
3695 {
3696 	int rc;
3697 	uint64_t objnum;
3698 	const spa_t *spa;
3699 	dnode_phys_t dn;
3700 	const char *p, *q;
3701 	char element[256];
3702 	char path[1024];
3703 	int symlinks_followed = 0;
3704 	struct stat sb;
3705 	struct obj_list *entry, *tentry;
3706 	STAILQ_HEAD(, obj_list) on_cache = STAILQ_HEAD_INITIALIZER(on_cache);
3707 
3708 	spa = mount->spa;
3709 	if (mount->objset.os_type != DMU_OST_ZFS) {
3710 		printf("ZFS: unexpected object set type %ju\n",
3711 		    (uintmax_t)mount->objset.os_type);
3712 		return (EIO);
3713 	}
3714 
3715 	if ((entry = malloc(sizeof(struct obj_list))) == NULL)
3716 		return (ENOMEM);
3717 
3718 	/*
3719 	 * Get the root directory dnode.
3720 	 */
3721 	rc = objset_get_dnode(spa, &mount->objset, MASTER_NODE_OBJ, &dn);
3722 	if (rc) {
3723 		free(entry);
3724 		return (rc);
3725 	}
3726 
3727 	rc = zap_lookup(spa, &dn, ZFS_ROOT_OBJ, sizeof(objnum), 1, &objnum);
3728 	if (rc) {
3729 		free(entry);
3730 		return (rc);
3731 	}
3732 	entry->objnum = objnum;
3733 	STAILQ_INSERT_HEAD(&on_cache, entry, entry);
3734 
3735 	rc = objset_get_dnode(spa, &mount->objset, objnum, &dn);
3736 	if (rc != 0)
3737 		goto done;
3738 
3739 	p = upath;
3740 	while (p && *p) {
3741 		rc = objset_get_dnode(spa, &mount->objset, objnum, &dn);
3742 		if (rc != 0)
3743 			goto done;
3744 
3745 		while (*p == '/')
3746 			p++;
3747 		if (*p == '\0')
3748 			break;
3749 		q = p;
3750 		while (*q != '\0' && *q != '/')
3751 			q++;
3752 
3753 		/* skip dot */
3754 		if (p + 1 == q && p[0] == '.') {
3755 			p++;
3756 			continue;
3757 		}
3758 		/* double dot */
3759 		if (p + 2 == q && p[0] == '.' && p[1] == '.') {
3760 			p += 2;
3761 			if (STAILQ_FIRST(&on_cache) ==
3762 			    STAILQ_LAST(&on_cache, obj_list, entry)) {
3763 				rc = ENOENT;
3764 				goto done;
3765 			}
3766 			entry = STAILQ_FIRST(&on_cache);
3767 			STAILQ_REMOVE_HEAD(&on_cache, entry);
3768 			free(entry);
3769 			objnum = (STAILQ_FIRST(&on_cache))->objnum;
3770 			continue;
3771 		}
3772 		if (q - p + 1 > sizeof(element)) {
3773 			rc = ENAMETOOLONG;
3774 			goto done;
3775 		}
3776 		memcpy(element, p, q - p);
3777 		element[q - p] = 0;
3778 		p = q;
3779 
3780 		if ((rc = zfs_dnode_stat(spa, &dn, &sb)) != 0)
3781 			goto done;
3782 		if (!S_ISDIR(sb.st_mode)) {
3783 			rc = ENOTDIR;
3784 			goto done;
3785 		}
3786 
3787 		rc = zap_lookup(spa, &dn, element, sizeof (objnum), 1, &objnum);
3788 		if (rc)
3789 			goto done;
3790 		objnum = ZFS_DIRENT_OBJ(objnum);
3791 
3792 		if ((entry = malloc(sizeof(struct obj_list))) == NULL) {
3793 			rc = ENOMEM;
3794 			goto done;
3795 		}
3796 		entry->objnum = objnum;
3797 		STAILQ_INSERT_HEAD(&on_cache, entry, entry);
3798 		rc = objset_get_dnode(spa, &mount->objset, objnum, &dn);
3799 		if (rc)
3800 			goto done;
3801 
3802 		/*
3803 		 * Check for symlink.
3804 		 */
3805 		rc = zfs_dnode_stat(spa, &dn, &sb);
3806 		if (rc)
3807 			goto done;
3808 		if (S_ISLNK(sb.st_mode)) {
3809 			if (symlinks_followed > 10) {
3810 				rc = EMLINK;
3811 				goto done;
3812 			}
3813 			symlinks_followed++;
3814 
3815 			/*
3816 			 * Read the link value and copy the tail of our
3817 			 * current path onto the end.
3818 			 */
3819 			if (sb.st_size + strlen(p) + 1 > sizeof(path)) {
3820 				rc = ENAMETOOLONG;
3821 				goto done;
3822 			}
3823 			strcpy(&path[sb.st_size], p);
3824 
3825 			rc = zfs_dnode_readlink(spa, &dn, path, sb.st_size);
3826 			if (rc != 0)
3827 				goto done;
3828 
3829 			/*
3830 			 * Restart with the new path, starting either at
3831 			 * the root or at the parent depending whether or
3832 			 * not the link is relative.
3833 			 */
3834 			p = path;
3835 			if (*p == '/') {
3836 				while (STAILQ_FIRST(&on_cache) !=
3837 				    STAILQ_LAST(&on_cache, obj_list, entry)) {
3838 					entry = STAILQ_FIRST(&on_cache);
3839 					STAILQ_REMOVE_HEAD(&on_cache, entry);
3840 					free(entry);
3841 				}
3842 			} else {
3843 				entry = STAILQ_FIRST(&on_cache);
3844 				STAILQ_REMOVE_HEAD(&on_cache, entry);
3845 				free(entry);
3846 			}
3847 			objnum = (STAILQ_FIRST(&on_cache))->objnum;
3848 		}
3849 	}
3850 
3851 	*dnode = dn;
3852 done:
3853 	STAILQ_FOREACH_SAFE(entry, &on_cache, entry, tentry)
3854 		free(entry);
3855 	return (rc);
3856 }
3857 
3858 /*
3859  * Return either a cached copy of the bootenv, or read each of the vdev children
3860  * looking for the bootenv. Cache what's found and return the results. Returns 0
3861  * when benvp is filled in, and some errno when not.
3862  */
3863 static int
3864 zfs_get_bootenv_spa(spa_t *spa, nvlist_t **benvp)
3865 {
3866 	vdev_t *vd;
3867 	nvlist_t *benv = NULL;
3868 
3869 	if (spa->spa_bootenv == NULL) {
3870 		STAILQ_FOREACH(vd, &spa->spa_root_vdev->v_children,
3871 		    v_childlink) {
3872 			benv = vdev_read_bootenv(vd);
3873 
3874 			if (benv != NULL)
3875 				break;
3876 		}
3877 		spa->spa_bootenv = benv;
3878 	}
3879 	benv = spa->spa_bootenv;
3880 
3881 	if (benv == NULL)
3882 		return (ENOENT);
3883 
3884 	*benvp = benv;
3885 	return (0);
3886 }
3887 
3888 /*
3889  * Store nvlist to pool label bootenv area. Also updates cached pointer in spa.
3890  */
3891 static int
3892 zfs_set_bootenv_spa(spa_t *spa, nvlist_t *benv)
3893 {
3894 	vdev_t *vd;
3895 
3896 	STAILQ_FOREACH(vd, &spa->spa_root_vdev->v_children, v_childlink) {
3897 		vdev_write_bootenv(vd, benv);
3898 	}
3899 
3900 	spa->spa_bootenv = benv;
3901 	return (0);
3902 }
3903 
3904 /*
3905  * Get bootonce value by key. The bootonce <key, value> pair is removed from the
3906  * bootenv nvlist and the remaining nvlist is committed back to disk. This process
3907  * the bootonce flag since we've reached the point in the boot that we've 'used'
3908  * the BE. For chained boot scenarios, we may reach this point multiple times (but
3909  * only remove it and return 0 the first time).
3910  */
3911 static int
3912 zfs_get_bootonce_spa(spa_t *spa, const char *key, char *buf, size_t size)
3913 {
3914 	nvlist_t *benv;
3915 	char *result = NULL;
3916 	int result_size, rv;
3917 
3918 	if ((rv = zfs_get_bootenv_spa(spa, &benv)) != 0)
3919 		return (rv);
3920 
3921 	if ((rv = nvlist_find(benv, key, DATA_TYPE_STRING, NULL,
3922 	    &result, &result_size)) == 0) {
3923 		if (result_size == 0) {
3924 			/* ignore empty string */
3925 			rv = ENOENT;
3926 		} else if (buf != NULL) {
3927 			size = MIN((size_t)result_size + 1, size);
3928 			strlcpy(buf, result, size);
3929 		}
3930 		(void)nvlist_remove(benv, key, DATA_TYPE_STRING);
3931 		(void)zfs_set_bootenv_spa(spa, benv);
3932 	}
3933 
3934 	return (rv);
3935 }
3936