xref: /freebsd/stand/libsa/zfs/zfsimpl.c (revision 0957b409)
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 <sys/stat.h>
35 #include <sys/stdint.h>
36 
37 #include "zfsimpl.h"
38 #include "zfssubr.c"
39 
40 
41 struct zfsmount {
42 	const spa_t	*spa;
43 	objset_phys_t	objset;
44 	uint64_t	rootobj;
45 };
46 static struct zfsmount zfsmount __unused;
47 
48 /*
49  * List of all vdevs, chained through v_alllink.
50  */
51 static vdev_list_t zfs_vdevs;
52 
53  /*
54  * List of ZFS features supported for read
55  */
56 static const char *features_for_read[] = {
57 	"org.illumos:lz4_compress",
58 	"com.delphix:hole_birth",
59 	"com.delphix:extensible_dataset",
60 	"com.delphix:embedded_data",
61 	"org.open-zfs:large_blocks",
62 	"org.illumos:sha512",
63 	"org.illumos:skein",
64 	"org.zfsonlinux:large_dnode",
65 	"com.joyent:multi_vdev_crash_dump",
66 	NULL
67 };
68 
69 /*
70  * List of all pools, chained through spa_link.
71  */
72 static spa_list_t zfs_pools;
73 
74 static const dnode_phys_t *dnode_cache_obj;
75 static uint64_t dnode_cache_bn;
76 static char *dnode_cache_buf;
77 static char *zap_scratch;
78 static char *zfs_temp_buf, *zfs_temp_end, *zfs_temp_ptr;
79 
80 #define TEMP_SIZE	(1024 * 1024)
81 
82 static int zio_read(const spa_t *spa, const blkptr_t *bp, void *buf);
83 static int zfs_get_root(const spa_t *spa, uint64_t *objid);
84 static int zfs_rlookup(const spa_t *spa, uint64_t objnum, char *result);
85 static int zap_lookup(const spa_t *spa, const dnode_phys_t *dnode,
86     const char *name, uint64_t integer_size, uint64_t num_integers,
87     void *value);
88 
89 static void
90 zfs_init(void)
91 {
92 	STAILQ_INIT(&zfs_vdevs);
93 	STAILQ_INIT(&zfs_pools);
94 
95 	zfs_temp_buf = malloc(TEMP_SIZE);
96 	zfs_temp_end = zfs_temp_buf + TEMP_SIZE;
97 	zfs_temp_ptr = zfs_temp_buf;
98 	dnode_cache_buf = malloc(SPA_MAXBLOCKSIZE);
99 	zap_scratch = malloc(SPA_MAXBLOCKSIZE);
100 
101 	zfs_init_crc();
102 }
103 
104 static void *
105 zfs_alloc(size_t size)
106 {
107 	char *ptr;
108 
109 	if (zfs_temp_ptr + size > zfs_temp_end) {
110 		printf("ZFS: out of temporary buffer space\n");
111 		for (;;) ;
112 	}
113 	ptr = zfs_temp_ptr;
114 	zfs_temp_ptr += size;
115 
116 	return (ptr);
117 }
118 
119 static void
120 zfs_free(void *ptr, size_t size)
121 {
122 
123 	zfs_temp_ptr -= size;
124 	if (zfs_temp_ptr != ptr) {
125 		printf("ZFS: zfs_alloc()/zfs_free() mismatch\n");
126 		for (;;) ;
127 	}
128 }
129 
130 static int
131 xdr_int(const unsigned char **xdr, int *ip)
132 {
133 	*ip = ((*xdr)[0] << 24)
134 		| ((*xdr)[1] << 16)
135 		| ((*xdr)[2] << 8)
136 		| ((*xdr)[3] << 0);
137 	(*xdr) += 4;
138 	return (0);
139 }
140 
141 static int
142 xdr_u_int(const unsigned char **xdr, u_int *ip)
143 {
144 	*ip = ((*xdr)[0] << 24)
145 		| ((*xdr)[1] << 16)
146 		| ((*xdr)[2] << 8)
147 		| ((*xdr)[3] << 0);
148 	(*xdr) += 4;
149 	return (0);
150 }
151 
152 static int
153 xdr_uint64_t(const unsigned char **xdr, uint64_t *lp)
154 {
155 	u_int hi, lo;
156 
157 	xdr_u_int(xdr, &hi);
158 	xdr_u_int(xdr, &lo);
159 	*lp = (((uint64_t) hi) << 32) | lo;
160 	return (0);
161 }
162 
163 static int
164 nvlist_find(const unsigned char *nvlist, const char *name, int type,
165 	    int* elementsp, void *valuep)
166 {
167 	const unsigned char *p, *pair;
168 	int junk;
169 	int encoded_size, decoded_size;
170 
171 	p = nvlist;
172 	xdr_int(&p, &junk);
173 	xdr_int(&p, &junk);
174 
175 	pair = p;
176 	xdr_int(&p, &encoded_size);
177 	xdr_int(&p, &decoded_size);
178 	while (encoded_size && decoded_size) {
179 		int namelen, pairtype, elements;
180 		const char *pairname;
181 
182 		xdr_int(&p, &namelen);
183 		pairname = (const char*) p;
184 		p += roundup(namelen, 4);
185 		xdr_int(&p, &pairtype);
186 
187 		if (!memcmp(name, pairname, namelen) && type == pairtype) {
188 			xdr_int(&p, &elements);
189 			if (elementsp)
190 				*elementsp = elements;
191 			if (type == DATA_TYPE_UINT64) {
192 				xdr_uint64_t(&p, (uint64_t *) valuep);
193 				return (0);
194 			} else if (type == DATA_TYPE_STRING) {
195 				int len;
196 				xdr_int(&p, &len);
197 				(*(const char**) valuep) = (const char*) p;
198 				return (0);
199 			} else if (type == DATA_TYPE_NVLIST
200 				   || type == DATA_TYPE_NVLIST_ARRAY) {
201 				(*(const unsigned char**) valuep) =
202 					 (const unsigned char*) p;
203 				return (0);
204 			} else {
205 				return (EIO);
206 			}
207 		} else {
208 			/*
209 			 * Not the pair we are looking for, skip to the next one.
210 			 */
211 			p = pair + encoded_size;
212 		}
213 
214 		pair = p;
215 		xdr_int(&p, &encoded_size);
216 		xdr_int(&p, &decoded_size);
217 	}
218 
219 	return (EIO);
220 }
221 
222 static int
223 nvlist_check_features_for_read(const unsigned char *nvlist)
224 {
225 	const unsigned char *p, *pair;
226 	int junk;
227 	int encoded_size, decoded_size;
228 	int rc;
229 
230 	rc = 0;
231 
232 	p = nvlist;
233 	xdr_int(&p, &junk);
234 	xdr_int(&p, &junk);
235 
236 	pair = p;
237 	xdr_int(&p, &encoded_size);
238 	xdr_int(&p, &decoded_size);
239 	while (encoded_size && decoded_size) {
240 		int namelen, pairtype;
241 		const char *pairname;
242 		int i, found;
243 
244 		found = 0;
245 
246 		xdr_int(&p, &namelen);
247 		pairname = (const char*) p;
248 		p += roundup(namelen, 4);
249 		xdr_int(&p, &pairtype);
250 
251 		for (i = 0; features_for_read[i] != NULL; i++) {
252 			if (!memcmp(pairname, features_for_read[i], namelen)) {
253 				found = 1;
254 				break;
255 			}
256 		}
257 
258 		if (!found) {
259 			printf("ZFS: unsupported feature: %s\n", pairname);
260 			rc = EIO;
261 		}
262 
263 		p = pair + encoded_size;
264 
265 		pair = p;
266 		xdr_int(&p, &encoded_size);
267 		xdr_int(&p, &decoded_size);
268 	}
269 
270 	return (rc);
271 }
272 
273 /*
274  * Return the next nvlist in an nvlist array.
275  */
276 static const unsigned char *
277 nvlist_next(const unsigned char *nvlist)
278 {
279 	const unsigned char *p, *pair;
280 	int junk;
281 	int encoded_size, decoded_size;
282 
283 	p = nvlist;
284 	xdr_int(&p, &junk);
285 	xdr_int(&p, &junk);
286 
287 	pair = p;
288 	xdr_int(&p, &encoded_size);
289 	xdr_int(&p, &decoded_size);
290 	while (encoded_size && decoded_size) {
291 		p = pair + encoded_size;
292 
293 		pair = p;
294 		xdr_int(&p, &encoded_size);
295 		xdr_int(&p, &decoded_size);
296 	}
297 
298 	return p;
299 }
300 
301 #ifdef TEST
302 
303 static const unsigned char *
304 nvlist_print(const unsigned char *nvlist, unsigned int indent)
305 {
306 	static const char* typenames[] = {
307 		"DATA_TYPE_UNKNOWN",
308 		"DATA_TYPE_BOOLEAN",
309 		"DATA_TYPE_BYTE",
310 		"DATA_TYPE_INT16",
311 		"DATA_TYPE_UINT16",
312 		"DATA_TYPE_INT32",
313 		"DATA_TYPE_UINT32",
314 		"DATA_TYPE_INT64",
315 		"DATA_TYPE_UINT64",
316 		"DATA_TYPE_STRING",
317 		"DATA_TYPE_BYTE_ARRAY",
318 		"DATA_TYPE_INT16_ARRAY",
319 		"DATA_TYPE_UINT16_ARRAY",
320 		"DATA_TYPE_INT32_ARRAY",
321 		"DATA_TYPE_UINT32_ARRAY",
322 		"DATA_TYPE_INT64_ARRAY",
323 		"DATA_TYPE_UINT64_ARRAY",
324 		"DATA_TYPE_STRING_ARRAY",
325 		"DATA_TYPE_HRTIME",
326 		"DATA_TYPE_NVLIST",
327 		"DATA_TYPE_NVLIST_ARRAY",
328 		"DATA_TYPE_BOOLEAN_VALUE",
329 		"DATA_TYPE_INT8",
330 		"DATA_TYPE_UINT8",
331 		"DATA_TYPE_BOOLEAN_ARRAY",
332 		"DATA_TYPE_INT8_ARRAY",
333 		"DATA_TYPE_UINT8_ARRAY"
334 	};
335 
336 	unsigned int i, j;
337 	const unsigned char *p, *pair;
338 	int junk;
339 	int encoded_size, decoded_size;
340 
341 	p = nvlist;
342 	xdr_int(&p, &junk);
343 	xdr_int(&p, &junk);
344 
345 	pair = p;
346 	xdr_int(&p, &encoded_size);
347 	xdr_int(&p, &decoded_size);
348 	while (encoded_size && decoded_size) {
349 		int namelen, pairtype, elements;
350 		const char *pairname;
351 
352 		xdr_int(&p, &namelen);
353 		pairname = (const char*) p;
354 		p += roundup(namelen, 4);
355 		xdr_int(&p, &pairtype);
356 
357 		for (i = 0; i < indent; i++)
358 			printf(" ");
359 		printf("%s %s", typenames[pairtype], pairname);
360 
361 		xdr_int(&p, &elements);
362 		switch (pairtype) {
363 		case DATA_TYPE_UINT64: {
364 			uint64_t val;
365 			xdr_uint64_t(&p, &val);
366 			printf(" = 0x%jx\n", (uintmax_t)val);
367 			break;
368 		}
369 
370 		case DATA_TYPE_STRING: {
371 			int len;
372 			xdr_int(&p, &len);
373 			printf(" = \"%s\"\n", p);
374 			break;
375 		}
376 
377 		case DATA_TYPE_NVLIST:
378 			printf("\n");
379 			nvlist_print(p, indent + 1);
380 			break;
381 
382 		case DATA_TYPE_NVLIST_ARRAY:
383 			for (j = 0; j < elements; j++) {
384 				printf("[%d]\n", j);
385 				p = nvlist_print(p, indent + 1);
386 				if (j != elements - 1) {
387 					for (i = 0; i < indent; i++)
388 						printf(" ");
389 					printf("%s %s", typenames[pairtype], pairname);
390 				}
391 			}
392 			break;
393 
394 		default:
395 			printf("\n");
396 		}
397 
398 		p = pair + encoded_size;
399 
400 		pair = p;
401 		xdr_int(&p, &encoded_size);
402 		xdr_int(&p, &decoded_size);
403 	}
404 
405 	return p;
406 }
407 
408 #endif
409 
410 static int
411 vdev_read_phys(vdev_t *vdev, const blkptr_t *bp, void *buf,
412     off_t offset, size_t size)
413 {
414 	size_t psize;
415 	int rc;
416 
417 	if (!vdev->v_phys_read)
418 		return (EIO);
419 
420 	if (bp) {
421 		psize = BP_GET_PSIZE(bp);
422 	} else {
423 		psize = size;
424 	}
425 
426 	/*printf("ZFS: reading %zu bytes at 0x%jx to %p\n", psize, (uintmax_t)offset, buf);*/
427 	rc = vdev->v_phys_read(vdev, vdev->v_read_priv, offset, buf, psize);
428 	if (rc)
429 		return (rc);
430 	if (bp && zio_checksum_verify(vdev->spa, bp, buf))
431 		return (EIO);
432 
433 	return (0);
434 }
435 
436 static int
437 vdev_disk_read(vdev_t *vdev, const blkptr_t *bp, void *buf,
438     off_t offset, size_t bytes)
439 {
440 
441 	return (vdev_read_phys(vdev, bp, buf,
442 		offset + VDEV_LABEL_START_SIZE, bytes));
443 }
444 
445 
446 static int
447 vdev_mirror_read(vdev_t *vdev, const blkptr_t *bp, void *buf,
448     off_t offset, size_t bytes)
449 {
450 	vdev_t *kid;
451 	int rc;
452 
453 	rc = EIO;
454 	STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
455 		if (kid->v_state != VDEV_STATE_HEALTHY)
456 			continue;
457 		rc = kid->v_read(kid, bp, buf, offset, bytes);
458 		if (!rc)
459 			return (0);
460 	}
461 
462 	return (rc);
463 }
464 
465 static int
466 vdev_replacing_read(vdev_t *vdev, const blkptr_t *bp, void *buf,
467     off_t offset, size_t bytes)
468 {
469 	vdev_t *kid;
470 
471 	/*
472 	 * Here we should have two kids:
473 	 * First one which is the one we are replacing and we can trust
474 	 * only this one to have valid data, but it might not be present.
475 	 * Second one is that one we are replacing with. It is most likely
476 	 * healthy, but we can't trust it has needed data, so we won't use it.
477 	 */
478 	kid = STAILQ_FIRST(&vdev->v_children);
479 	if (kid == NULL)
480 		return (EIO);
481 	if (kid->v_state != VDEV_STATE_HEALTHY)
482 		return (EIO);
483 	return (kid->v_read(kid, bp, buf, offset, bytes));
484 }
485 
486 static vdev_t *
487 vdev_find(uint64_t guid)
488 {
489 	vdev_t *vdev;
490 
491 	STAILQ_FOREACH(vdev, &zfs_vdevs, v_alllink)
492 		if (vdev->v_guid == guid)
493 			return (vdev);
494 
495 	return (0);
496 }
497 
498 static vdev_t *
499 vdev_create(uint64_t guid, vdev_read_t *_read)
500 {
501 	vdev_t *vdev;
502 
503 	vdev = malloc(sizeof(vdev_t));
504 	memset(vdev, 0, sizeof(vdev_t));
505 	STAILQ_INIT(&vdev->v_children);
506 	vdev->v_guid = guid;
507 	vdev->v_state = VDEV_STATE_OFFLINE;
508 	vdev->v_read = _read;
509 	vdev->v_phys_read = 0;
510 	vdev->v_read_priv = 0;
511 	STAILQ_INSERT_TAIL(&zfs_vdevs, vdev, v_alllink);
512 
513 	return (vdev);
514 }
515 
516 static int
517 vdev_init_from_nvlist(const unsigned char *nvlist, vdev_t *pvdev,
518     vdev_t **vdevp, int is_newer)
519 {
520 	int rc;
521 	uint64_t guid, id, ashift, nparity;
522 	const char *type;
523 	const char *path;
524 	vdev_t *vdev, *kid;
525 	const unsigned char *kids;
526 	int nkids, i, is_new;
527 	uint64_t is_offline, is_faulted, is_degraded, is_removed, isnt_present;
528 
529 	if (nvlist_find(nvlist, ZPOOL_CONFIG_GUID, DATA_TYPE_UINT64,
530 	    NULL, &guid)
531 	    || nvlist_find(nvlist, ZPOOL_CONFIG_ID, DATA_TYPE_UINT64, NULL, &id)
532 	    || nvlist_find(nvlist, ZPOOL_CONFIG_TYPE, DATA_TYPE_STRING,
533 	    NULL, &type)) {
534 		printf("ZFS: can't find vdev details\n");
535 		return (ENOENT);
536 	}
537 
538 	if (strcmp(type, VDEV_TYPE_MIRROR)
539 	    && strcmp(type, VDEV_TYPE_DISK)
540 #ifdef ZFS_TEST
541 	    && strcmp(type, VDEV_TYPE_FILE)
542 #endif
543 	    && strcmp(type, VDEV_TYPE_RAIDZ)
544 	    && strcmp(type, VDEV_TYPE_REPLACING)) {
545 		printf("ZFS: can only boot from disk, mirror, raidz1, raidz2 and raidz3 vdevs\n");
546 		return (EIO);
547 	}
548 
549 	is_offline = is_removed = is_faulted = is_degraded = isnt_present = 0;
550 
551 	nvlist_find(nvlist, ZPOOL_CONFIG_OFFLINE, DATA_TYPE_UINT64, NULL,
552 			&is_offline);
553 	nvlist_find(nvlist, ZPOOL_CONFIG_REMOVED, DATA_TYPE_UINT64, NULL,
554 			&is_removed);
555 	nvlist_find(nvlist, ZPOOL_CONFIG_FAULTED, DATA_TYPE_UINT64, NULL,
556 			&is_faulted);
557 	nvlist_find(nvlist, ZPOOL_CONFIG_DEGRADED, DATA_TYPE_UINT64, NULL,
558 			&is_degraded);
559 	nvlist_find(nvlist, ZPOOL_CONFIG_NOT_PRESENT, DATA_TYPE_UINT64, NULL,
560 			&isnt_present);
561 
562 	vdev = vdev_find(guid);
563 	if (!vdev) {
564 		is_new = 1;
565 
566 		if (!strcmp(type, VDEV_TYPE_MIRROR))
567 			vdev = vdev_create(guid, vdev_mirror_read);
568 		else if (!strcmp(type, VDEV_TYPE_RAIDZ))
569 			vdev = vdev_create(guid, vdev_raidz_read);
570 		else if (!strcmp(type, VDEV_TYPE_REPLACING))
571 			vdev = vdev_create(guid, vdev_replacing_read);
572 		else
573 			vdev = vdev_create(guid, vdev_disk_read);
574 
575 		vdev->v_id = id;
576 		vdev->v_top = pvdev != NULL ? pvdev : vdev;
577 		if (nvlist_find(nvlist, ZPOOL_CONFIG_ASHIFT,
578 			DATA_TYPE_UINT64, NULL, &ashift) == 0) {
579 			vdev->v_ashift = ashift;
580 		} else {
581 			vdev->v_ashift = 0;
582 		}
583 		if (nvlist_find(nvlist, ZPOOL_CONFIG_NPARITY,
584 			DATA_TYPE_UINT64, NULL, &nparity) == 0) {
585 			vdev->v_nparity = nparity;
586 		} else {
587 			vdev->v_nparity = 0;
588 		}
589 		if (nvlist_find(nvlist, ZPOOL_CONFIG_PATH,
590 				DATA_TYPE_STRING, NULL, &path) == 0) {
591 			if (strncmp(path, "/dev/", 5) == 0)
592 				path += 5;
593 			vdev->v_name = strdup(path);
594 		} else {
595 			if (!strcmp(type, "raidz")) {
596 				if (vdev->v_nparity == 1)
597 					vdev->v_name = "raidz1";
598 				else if (vdev->v_nparity == 2)
599 					vdev->v_name = "raidz2";
600 				else if (vdev->v_nparity == 3)
601 					vdev->v_name = "raidz3";
602 				else {
603 					printf("ZFS: can only boot from disk, mirror, raidz1, raidz2 and raidz3 vdevs\n");
604 					return (EIO);
605 				}
606 			} else {
607 				vdev->v_name = strdup(type);
608 			}
609 		}
610 	} else {
611 		is_new = 0;
612 	}
613 
614 	if (is_new || is_newer) {
615 		/*
616 		 * This is either new vdev or we've already seen this vdev,
617 		 * but from an older vdev label, so let's refresh its state
618 		 * from the newer label.
619 		 */
620 		if (is_offline)
621 			vdev->v_state = VDEV_STATE_OFFLINE;
622 		else if (is_removed)
623 			vdev->v_state = VDEV_STATE_REMOVED;
624 		else if (is_faulted)
625 			vdev->v_state = VDEV_STATE_FAULTED;
626 		else if (is_degraded)
627 			vdev->v_state = VDEV_STATE_DEGRADED;
628 		else if (isnt_present)
629 			vdev->v_state = VDEV_STATE_CANT_OPEN;
630 	}
631 
632 	rc = nvlist_find(nvlist, ZPOOL_CONFIG_CHILDREN, DATA_TYPE_NVLIST_ARRAY,
633 	    &nkids, &kids);
634 	/*
635 	 * Its ok if we don't have any kids.
636 	 */
637 	if (rc == 0) {
638 		vdev->v_nchildren = nkids;
639 		for (i = 0; i < nkids; i++) {
640 			rc = vdev_init_from_nvlist(kids, vdev, &kid, is_newer);
641 			if (rc)
642 				return (rc);
643 			if (is_new)
644 				STAILQ_INSERT_TAIL(&vdev->v_children, kid,
645 						   v_childlink);
646 			kids = nvlist_next(kids);
647 		}
648 	} else {
649 		vdev->v_nchildren = 0;
650 	}
651 
652 	if (vdevp)
653 		*vdevp = vdev;
654 	return (0);
655 }
656 
657 static void
658 vdev_set_state(vdev_t *vdev)
659 {
660 	vdev_t *kid;
661 	int good_kids;
662 	int bad_kids;
663 
664 	/*
665 	 * A mirror or raidz is healthy if all its kids are healthy. A
666 	 * mirror is degraded if any of its kids is healthy; a raidz
667 	 * is degraded if at most nparity kids are offline.
668 	 */
669 	if (STAILQ_FIRST(&vdev->v_children)) {
670 		good_kids = 0;
671 		bad_kids = 0;
672 		STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
673 			if (kid->v_state == VDEV_STATE_HEALTHY)
674 				good_kids++;
675 			else
676 				bad_kids++;
677 		}
678 		if (bad_kids == 0) {
679 			vdev->v_state = VDEV_STATE_HEALTHY;
680 		} else {
681 			if (vdev->v_read == vdev_mirror_read) {
682 				if (good_kids) {
683 					vdev->v_state = VDEV_STATE_DEGRADED;
684 				} else {
685 					vdev->v_state = VDEV_STATE_OFFLINE;
686 				}
687 			} else if (vdev->v_read == vdev_raidz_read) {
688 				if (bad_kids > vdev->v_nparity) {
689 					vdev->v_state = VDEV_STATE_OFFLINE;
690 				} else {
691 					vdev->v_state = VDEV_STATE_DEGRADED;
692 				}
693 			}
694 		}
695 	}
696 }
697 
698 static spa_t *
699 spa_find_by_guid(uint64_t guid)
700 {
701 	spa_t *spa;
702 
703 	STAILQ_FOREACH(spa, &zfs_pools, spa_link)
704 		if (spa->spa_guid == guid)
705 			return (spa);
706 
707 	return (0);
708 }
709 
710 static spa_t *
711 spa_find_by_name(const char *name)
712 {
713 	spa_t *spa;
714 
715 	STAILQ_FOREACH(spa, &zfs_pools, spa_link)
716 		if (!strcmp(spa->spa_name, name))
717 			return (spa);
718 
719 	return (0);
720 }
721 
722 #ifdef BOOT2
723 static spa_t *
724 spa_get_primary(void)
725 {
726 
727 	return (STAILQ_FIRST(&zfs_pools));
728 }
729 
730 static vdev_t *
731 spa_get_primary_vdev(const spa_t *spa)
732 {
733 	vdev_t *vdev;
734 	vdev_t *kid;
735 
736 	if (spa == NULL)
737 		spa = spa_get_primary();
738 	if (spa == NULL)
739 		return (NULL);
740 	vdev = STAILQ_FIRST(&spa->spa_vdevs);
741 	if (vdev == NULL)
742 		return (NULL);
743 	for (kid = STAILQ_FIRST(&vdev->v_children); kid != NULL;
744 	     kid = STAILQ_FIRST(&vdev->v_children))
745 		vdev = kid;
746 	return (vdev);
747 }
748 #endif
749 
750 static spa_t *
751 spa_create(uint64_t guid, const char *name)
752 {
753 	spa_t *spa;
754 
755 	if ((spa = malloc(sizeof(spa_t))) == NULL)
756 		return (NULL);
757 	memset(spa, 0, sizeof(spa_t));
758 	if ((spa->spa_name = strdup(name)) == NULL) {
759 		free(spa);
760 		return (NULL);
761 	}
762 	STAILQ_INIT(&spa->spa_vdevs);
763 	spa->spa_guid = guid;
764 	STAILQ_INSERT_TAIL(&zfs_pools, spa, spa_link);
765 
766 	return (spa);
767 }
768 
769 static const char *
770 state_name(vdev_state_t state)
771 {
772 	static const char* names[] = {
773 		"UNKNOWN",
774 		"CLOSED",
775 		"OFFLINE",
776 		"REMOVED",
777 		"CANT_OPEN",
778 		"FAULTED",
779 		"DEGRADED",
780 		"ONLINE"
781 	};
782 	return names[state];
783 }
784 
785 #ifdef BOOT2
786 
787 #define pager_printf printf
788 
789 #else
790 
791 static int
792 pager_printf(const char *fmt, ...)
793 {
794 	char line[80];
795 	va_list args;
796 
797 	va_start(args, fmt);
798 	vsprintf(line, fmt, args);
799 	va_end(args);
800 
801 	return (pager_output(line));
802 }
803 
804 #endif
805 
806 #define STATUS_FORMAT	"        %s %s\n"
807 
808 static int
809 print_state(int indent, const char *name, vdev_state_t state)
810 {
811 	char buf[512];
812 	int i;
813 
814 	buf[0] = 0;
815 	for (i = 0; i < indent; i++)
816 		strcat(buf, "  ");
817 	strcat(buf, name);
818 
819 	return (pager_printf(STATUS_FORMAT, buf, state_name(state)));
820 }
821 
822 static int
823 vdev_status(vdev_t *vdev, int indent)
824 {
825 	vdev_t *kid;
826 	int ret;
827 	ret = print_state(indent, vdev->v_name, vdev->v_state);
828 	if (ret != 0)
829 		return (ret);
830 
831 	STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
832 		ret = vdev_status(kid, indent + 1);
833 		if (ret != 0)
834 			return (ret);
835 	}
836 	return (ret);
837 }
838 
839 static int
840 spa_status(spa_t *spa)
841 {
842 	static char bootfs[ZFS_MAXNAMELEN];
843 	uint64_t rootid;
844 	vdev_t *vdev;
845 	int good_kids, bad_kids, degraded_kids, ret;
846 	vdev_state_t state;
847 
848 	ret = pager_printf("  pool: %s\n", spa->spa_name);
849 	if (ret != 0)
850 		return (ret);
851 
852 	if (zfs_get_root(spa, &rootid) == 0 &&
853 	    zfs_rlookup(spa, rootid, bootfs) == 0) {
854 		if (bootfs[0] == '\0')
855 			ret = pager_printf("bootfs: %s\n", spa->spa_name);
856 		else
857 			ret = pager_printf("bootfs: %s/%s\n", spa->spa_name,
858 			    bootfs);
859 		if (ret != 0)
860 			return (ret);
861 	}
862 	ret = pager_printf("config:\n\n");
863 	if (ret != 0)
864 		return (ret);
865 	ret = pager_printf(STATUS_FORMAT, "NAME", "STATE");
866 	if (ret != 0)
867 		return (ret);
868 
869 	good_kids = 0;
870 	degraded_kids = 0;
871 	bad_kids = 0;
872 	STAILQ_FOREACH(vdev, &spa->spa_vdevs, v_childlink) {
873 		if (vdev->v_state == VDEV_STATE_HEALTHY)
874 			good_kids++;
875 		else if (vdev->v_state == VDEV_STATE_DEGRADED)
876 			degraded_kids++;
877 		else
878 			bad_kids++;
879 	}
880 
881 	state = VDEV_STATE_CLOSED;
882 	if (good_kids > 0 && (degraded_kids + bad_kids) == 0)
883 		state = VDEV_STATE_HEALTHY;
884 	else if ((good_kids + degraded_kids) > 0)
885 		state = VDEV_STATE_DEGRADED;
886 
887 	ret = print_state(0, spa->spa_name, state);
888 	if (ret != 0)
889 		return (ret);
890 	STAILQ_FOREACH(vdev, &spa->spa_vdevs, v_childlink) {
891 		ret = vdev_status(vdev, 1);
892 		if (ret != 0)
893 			return (ret);
894 	}
895 	return (ret);
896 }
897 
898 static int
899 spa_all_status(void)
900 {
901 	spa_t *spa;
902 	int first = 1, ret = 0;
903 
904 	STAILQ_FOREACH(spa, &zfs_pools, spa_link) {
905 		if (!first) {
906 			ret = pager_printf("\n");
907 			if (ret != 0)
908 				return (ret);
909 		}
910 		first = 0;
911 		ret = spa_status(spa);
912 		if (ret != 0)
913 			return (ret);
914 	}
915 	return (ret);
916 }
917 
918 static uint64_t
919 vdev_label_offset(uint64_t psize, int l, uint64_t offset)
920 {
921 	uint64_t label_offset;
922 
923 	if (l < VDEV_LABELS / 2)
924 		label_offset = 0;
925 	else
926 		label_offset = psize - VDEV_LABELS * sizeof (vdev_label_t);
927 
928 	return (offset + l * sizeof (vdev_label_t) + label_offset);
929 }
930 
931 static int
932 vdev_probe(vdev_phys_read_t *_read, void *read_priv, spa_t **spap)
933 {
934 	vdev_t vtmp;
935 	vdev_phys_t *vdev_label = (vdev_phys_t *) zap_scratch;
936 	vdev_phys_t *tmp_label;
937 	spa_t *spa;
938 	vdev_t *vdev, *top_vdev, *pool_vdev;
939 	off_t off;
940 	blkptr_t bp;
941 	const unsigned char *nvlist = NULL;
942 	uint64_t val;
943 	uint64_t guid;
944 	uint64_t best_txg = 0;
945 	uint64_t pool_txg, pool_guid;
946 	uint64_t psize;
947 	const char *pool_name;
948 	const unsigned char *vdevs;
949 	const unsigned char *features;
950 	int i, l, rc, is_newer;
951 	char *upbuf;
952 	const struct uberblock *up;
953 
954 	/*
955 	 * Load the vdev label and figure out which
956 	 * uberblock is most current.
957 	 */
958 	memset(&vtmp, 0, sizeof(vtmp));
959 	vtmp.v_phys_read = _read;
960 	vtmp.v_read_priv = read_priv;
961 	psize = P2ALIGN(ldi_get_size(read_priv),
962 	    (uint64_t)sizeof (vdev_label_t));
963 
964 	/* Test for minimum pool size. */
965 	if (psize < SPA_MINDEVSIZE)
966 		return (EIO);
967 
968 	tmp_label = zfs_alloc(sizeof(vdev_phys_t));
969 
970 	for (l = 0; l < VDEV_LABELS; l++) {
971 		off = vdev_label_offset(psize, l,
972 		    offsetof(vdev_label_t, vl_vdev_phys));
973 
974 		BP_ZERO(&bp);
975 		BP_SET_LSIZE(&bp, sizeof(vdev_phys_t));
976 		BP_SET_PSIZE(&bp, sizeof(vdev_phys_t));
977 		BP_SET_CHECKSUM(&bp, ZIO_CHECKSUM_LABEL);
978 		BP_SET_COMPRESS(&bp, ZIO_COMPRESS_OFF);
979 		DVA_SET_OFFSET(BP_IDENTITY(&bp), off);
980 		ZIO_SET_CHECKSUM(&bp.blk_cksum, off, 0, 0, 0);
981 
982 		if (vdev_read_phys(&vtmp, &bp, tmp_label, off, 0))
983 			continue;
984 
985 		if (tmp_label->vp_nvlist[0] != NV_ENCODE_XDR)
986 			continue;
987 
988 		nvlist = (const unsigned char *) tmp_label->vp_nvlist + 4;
989 		if (nvlist_find(nvlist, ZPOOL_CONFIG_POOL_TXG,
990 		    DATA_TYPE_UINT64, NULL, &pool_txg) != 0)
991 			continue;
992 
993 		if (best_txg <= pool_txg) {
994 			best_txg = pool_txg;
995 			memcpy(vdev_label, tmp_label, sizeof (vdev_phys_t));
996 		}
997 	}
998 
999 	zfs_free(tmp_label, sizeof (vdev_phys_t));
1000 
1001 	if (best_txg == 0)
1002 		return (EIO);
1003 
1004 	if (vdev_label->vp_nvlist[0] != NV_ENCODE_XDR)
1005 		return (EIO);
1006 
1007 	nvlist = (const unsigned char *) vdev_label->vp_nvlist + 4;
1008 
1009 	if (nvlist_find(nvlist, ZPOOL_CONFIG_VERSION, DATA_TYPE_UINT64,
1010 	    NULL, &val) != 0) {
1011 		return (EIO);
1012 	}
1013 
1014 	if (!SPA_VERSION_IS_SUPPORTED(val)) {
1015 		printf("ZFS: unsupported ZFS version %u (should be %u)\n",
1016 		    (unsigned) val, (unsigned) SPA_VERSION);
1017 		return (EIO);
1018 	}
1019 
1020 	/* Check ZFS features for read */
1021 	if (nvlist_find(nvlist, ZPOOL_CONFIG_FEATURES_FOR_READ,
1022 	    DATA_TYPE_NVLIST, NULL, &features) == 0 &&
1023 	    nvlist_check_features_for_read(features) != 0) {
1024 		return (EIO);
1025 	}
1026 
1027 	if (nvlist_find(nvlist, ZPOOL_CONFIG_POOL_STATE, DATA_TYPE_UINT64,
1028 	    NULL, &val) != 0) {
1029 		return (EIO);
1030 	}
1031 
1032 	if (val == POOL_STATE_DESTROYED) {
1033 		/* We don't boot only from destroyed pools. */
1034 		return (EIO);
1035 	}
1036 
1037 	if (nvlist_find(nvlist, ZPOOL_CONFIG_POOL_TXG, DATA_TYPE_UINT64,
1038 	    NULL, &pool_txg) != 0 ||
1039 	    nvlist_find(nvlist, ZPOOL_CONFIG_POOL_GUID, DATA_TYPE_UINT64,
1040 	    NULL, &pool_guid) != 0 ||
1041 	    nvlist_find(nvlist, ZPOOL_CONFIG_POOL_NAME, DATA_TYPE_STRING,
1042 	    NULL, &pool_name) != 0) {
1043 		/*
1044 		 * Cache and spare devices end up here - just ignore
1045 		 * them.
1046 		 */
1047 		/*printf("ZFS: can't find pool details\n");*/
1048 		return (EIO);
1049 	}
1050 
1051 	if (nvlist_find(nvlist, ZPOOL_CONFIG_IS_LOG, DATA_TYPE_UINT64,
1052 	    NULL, &val) == 0 && val != 0) {
1053 		return (EIO);
1054 	}
1055 
1056 	/*
1057 	 * Create the pool if this is the first time we've seen it.
1058 	 */
1059 	spa = spa_find_by_guid(pool_guid);
1060 	if (spa == NULL) {
1061 		spa = spa_create(pool_guid, pool_name);
1062 		if (spa == NULL)
1063 			return (ENOMEM);
1064 	}
1065 	if (pool_txg > spa->spa_txg) {
1066 		spa->spa_txg = pool_txg;
1067 		is_newer = 1;
1068 	} else {
1069 		is_newer = 0;
1070 	}
1071 
1072 	/*
1073 	 * Get the vdev tree and create our in-core copy of it.
1074 	 * If we already have a vdev with this guid, this must
1075 	 * be some kind of alias (overlapping slices, dangerously dedicated
1076 	 * disks etc).
1077 	 */
1078 	if (nvlist_find(nvlist, ZPOOL_CONFIG_GUID, DATA_TYPE_UINT64,
1079 	    NULL, &guid) != 0) {
1080 		return (EIO);
1081 	}
1082 	vdev = vdev_find(guid);
1083 	if (vdev && vdev->v_phys_read)	/* Has this vdev already been inited? */
1084 		return (EIO);
1085 
1086 	if (nvlist_find(nvlist, ZPOOL_CONFIG_VDEV_TREE, DATA_TYPE_NVLIST,
1087 	    NULL, &vdevs)) {
1088 		return (EIO);
1089 	}
1090 
1091 	rc = vdev_init_from_nvlist(vdevs, NULL, &top_vdev, is_newer);
1092 	if (rc != 0)
1093 		return (rc);
1094 
1095 	/*
1096 	 * Add the toplevel vdev to the pool if its not already there.
1097 	 */
1098 	STAILQ_FOREACH(pool_vdev, &spa->spa_vdevs, v_childlink)
1099 		if (top_vdev == pool_vdev)
1100 			break;
1101 	if (!pool_vdev && top_vdev) {
1102 		top_vdev->spa = spa;
1103 		STAILQ_INSERT_TAIL(&spa->spa_vdevs, top_vdev, v_childlink);
1104 	}
1105 
1106 	/*
1107 	 * We should already have created an incomplete vdev for this
1108 	 * vdev. Find it and initialise it with our read proc.
1109 	 */
1110 	vdev = vdev_find(guid);
1111 	if (vdev) {
1112 		vdev->v_phys_read = _read;
1113 		vdev->v_read_priv = read_priv;
1114 		vdev->v_state = VDEV_STATE_HEALTHY;
1115 	} else {
1116 		printf("ZFS: inconsistent nvlist contents\n");
1117 		return (EIO);
1118 	}
1119 
1120 	/*
1121 	 * Re-evaluate top-level vdev state.
1122 	 */
1123 	vdev_set_state(top_vdev);
1124 
1125 	/*
1126 	 * Ok, we are happy with the pool so far. Lets find
1127 	 * the best uberblock and then we can actually access
1128 	 * the contents of the pool.
1129 	 */
1130 	upbuf = zfs_alloc(VDEV_UBERBLOCK_SIZE(vdev));
1131 	up = (const struct uberblock *)upbuf;
1132 	for (l = 0; l < VDEV_LABELS; l++) {
1133 		for (i = 0; i < VDEV_UBERBLOCK_COUNT(vdev); i++) {
1134 			off = vdev_label_offset(psize, l,
1135 			    VDEV_UBERBLOCK_OFFSET(vdev, i));
1136 			BP_ZERO(&bp);
1137 			DVA_SET_OFFSET(&bp.blk_dva[0], off);
1138 			BP_SET_LSIZE(&bp, VDEV_UBERBLOCK_SIZE(vdev));
1139 			BP_SET_PSIZE(&bp, VDEV_UBERBLOCK_SIZE(vdev));
1140 			BP_SET_CHECKSUM(&bp, ZIO_CHECKSUM_LABEL);
1141 			BP_SET_COMPRESS(&bp, ZIO_COMPRESS_OFF);
1142 			ZIO_SET_CHECKSUM(&bp.blk_cksum, off, 0, 0, 0);
1143 
1144 			if (vdev_read_phys(vdev, &bp, upbuf, off, 0))
1145 				continue;
1146 
1147 			if (up->ub_magic != UBERBLOCK_MAGIC)
1148 				continue;
1149 			if (up->ub_txg < spa->spa_txg)
1150 				continue;
1151 			if (up->ub_txg > spa->spa_uberblock.ub_txg ||
1152 			    (up->ub_txg == spa->spa_uberblock.ub_txg &&
1153 			    up->ub_timestamp >
1154 			    spa->spa_uberblock.ub_timestamp)) {
1155 				spa->spa_uberblock = *up;
1156 			}
1157 		}
1158 	}
1159 	zfs_free(upbuf, VDEV_UBERBLOCK_SIZE(vdev));
1160 
1161 	vdev->spa = spa;
1162 	if (spap != NULL)
1163 		*spap = spa;
1164 	return (0);
1165 }
1166 
1167 static int
1168 ilog2(int n)
1169 {
1170 	int v;
1171 
1172 	for (v = 0; v < 32; v++)
1173 		if (n == (1 << v))
1174 			return v;
1175 	return -1;
1176 }
1177 
1178 static int
1179 zio_read_gang(const spa_t *spa, const blkptr_t *bp, void *buf)
1180 {
1181 	blkptr_t gbh_bp;
1182 	zio_gbh_phys_t zio_gb;
1183 	char *pbuf;
1184 	int i;
1185 
1186 	/* Artificial BP for gang block header. */
1187 	gbh_bp = *bp;
1188 	BP_SET_PSIZE(&gbh_bp, SPA_GANGBLOCKSIZE);
1189 	BP_SET_LSIZE(&gbh_bp, SPA_GANGBLOCKSIZE);
1190 	BP_SET_CHECKSUM(&gbh_bp, ZIO_CHECKSUM_GANG_HEADER);
1191 	BP_SET_COMPRESS(&gbh_bp, ZIO_COMPRESS_OFF);
1192 	for (i = 0; i < SPA_DVAS_PER_BP; i++)
1193 		DVA_SET_GANG(&gbh_bp.blk_dva[i], 0);
1194 
1195 	/* Read gang header block using the artificial BP. */
1196 	if (zio_read(spa, &gbh_bp, &zio_gb))
1197 		return (EIO);
1198 
1199 	pbuf = buf;
1200 	for (i = 0; i < SPA_GBH_NBLKPTRS; i++) {
1201 		blkptr_t *gbp = &zio_gb.zg_blkptr[i];
1202 
1203 		if (BP_IS_HOLE(gbp))
1204 			continue;
1205 		if (zio_read(spa, gbp, pbuf))
1206 			return (EIO);
1207 		pbuf += BP_GET_PSIZE(gbp);
1208 	}
1209 
1210 	if (zio_checksum_verify(spa, bp, buf))
1211 		return (EIO);
1212 	return (0);
1213 }
1214 
1215 static int
1216 zio_read(const spa_t *spa, const blkptr_t *bp, void *buf)
1217 {
1218 	int cpfunc = BP_GET_COMPRESS(bp);
1219 	uint64_t align, size;
1220 	void *pbuf;
1221 	int i, error;
1222 
1223 	/*
1224 	 * Process data embedded in block pointer
1225 	 */
1226 	if (BP_IS_EMBEDDED(bp)) {
1227 		ASSERT(BPE_GET_ETYPE(bp) == BP_EMBEDDED_TYPE_DATA);
1228 
1229 		size = BPE_GET_PSIZE(bp);
1230 		ASSERT(size <= BPE_PAYLOAD_SIZE);
1231 
1232 		if (cpfunc != ZIO_COMPRESS_OFF)
1233 			pbuf = zfs_alloc(size);
1234 		else
1235 			pbuf = buf;
1236 
1237 		decode_embedded_bp_compressed(bp, pbuf);
1238 		error = 0;
1239 
1240 		if (cpfunc != ZIO_COMPRESS_OFF) {
1241 			error = zio_decompress_data(cpfunc, pbuf,
1242 			    size, buf, BP_GET_LSIZE(bp));
1243 			zfs_free(pbuf, size);
1244 		}
1245 		if (error != 0)
1246 			printf("ZFS: i/o error - unable to decompress block pointer data, error %d\n",
1247 			    error);
1248 		return (error);
1249 	}
1250 
1251 	error = EIO;
1252 
1253 	for (i = 0; i < SPA_DVAS_PER_BP; i++) {
1254 		const dva_t *dva = &bp->blk_dva[i];
1255 		vdev_t *vdev;
1256 		int vdevid;
1257 		off_t offset;
1258 
1259 		if (!dva->dva_word[0] && !dva->dva_word[1])
1260 			continue;
1261 
1262 		vdevid = DVA_GET_VDEV(dva);
1263 		offset = DVA_GET_OFFSET(dva);
1264 		STAILQ_FOREACH(vdev, &spa->spa_vdevs, v_childlink) {
1265 			if (vdev->v_id == vdevid)
1266 				break;
1267 		}
1268 		if (!vdev || !vdev->v_read)
1269 			continue;
1270 
1271 		size = BP_GET_PSIZE(bp);
1272 		if (vdev->v_read == vdev_raidz_read) {
1273 			align = 1ULL << vdev->v_top->v_ashift;
1274 			if (P2PHASE(size, align) != 0)
1275 				size = P2ROUNDUP(size, align);
1276 		}
1277 		if (size != BP_GET_PSIZE(bp) || cpfunc != ZIO_COMPRESS_OFF)
1278 			pbuf = zfs_alloc(size);
1279 		else
1280 			pbuf = buf;
1281 
1282 		if (DVA_GET_GANG(dva))
1283 			error = zio_read_gang(spa, bp, pbuf);
1284 		else
1285 			error = vdev->v_read(vdev, bp, pbuf, offset, size);
1286 		if (error == 0) {
1287 			if (cpfunc != ZIO_COMPRESS_OFF)
1288 				error = zio_decompress_data(cpfunc, pbuf,
1289 				    BP_GET_PSIZE(bp), buf, BP_GET_LSIZE(bp));
1290 			else if (size != BP_GET_PSIZE(bp))
1291 				bcopy(pbuf, buf, BP_GET_PSIZE(bp));
1292 		}
1293 		if (buf != pbuf)
1294 			zfs_free(pbuf, size);
1295 		if (error == 0)
1296 			break;
1297 	}
1298 	if (error != 0)
1299 		printf("ZFS: i/o error - all block copies unavailable\n");
1300 	return (error);
1301 }
1302 
1303 static int
1304 dnode_read(const spa_t *spa, const dnode_phys_t *dnode, off_t offset, void *buf, size_t buflen)
1305 {
1306 	int ibshift = dnode->dn_indblkshift - SPA_BLKPTRSHIFT;
1307 	int bsize = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
1308 	int nlevels = dnode->dn_nlevels;
1309 	int i, rc;
1310 
1311 	if (bsize > SPA_MAXBLOCKSIZE) {
1312 		printf("ZFS: I/O error - blocks larger than %llu are not "
1313 		    "supported\n", SPA_MAXBLOCKSIZE);
1314 		return (EIO);
1315 	}
1316 
1317 	/*
1318 	 * Note: bsize may not be a power of two here so we need to do an
1319 	 * actual divide rather than a bitshift.
1320 	 */
1321 	while (buflen > 0) {
1322 		uint64_t bn = offset / bsize;
1323 		int boff = offset % bsize;
1324 		int ibn;
1325 		const blkptr_t *indbp;
1326 		blkptr_t bp;
1327 
1328 		if (bn > dnode->dn_maxblkid)
1329 			return (EIO);
1330 
1331 		if (dnode == dnode_cache_obj && bn == dnode_cache_bn)
1332 			goto cached;
1333 
1334 		indbp = dnode->dn_blkptr;
1335 		for (i = 0; i < nlevels; i++) {
1336 			/*
1337 			 * Copy the bp from the indirect array so that
1338 			 * we can re-use the scratch buffer for multi-level
1339 			 * objects.
1340 			 */
1341 			ibn = bn >> ((nlevels - i - 1) * ibshift);
1342 			ibn &= ((1 << ibshift) - 1);
1343 			bp = indbp[ibn];
1344 			if (BP_IS_HOLE(&bp)) {
1345 				memset(dnode_cache_buf, 0, bsize);
1346 				break;
1347 			}
1348 			rc = zio_read(spa, &bp, dnode_cache_buf);
1349 			if (rc)
1350 				return (rc);
1351 			indbp = (const blkptr_t *) dnode_cache_buf;
1352 		}
1353 		dnode_cache_obj = dnode;
1354 		dnode_cache_bn = bn;
1355 	cached:
1356 
1357 		/*
1358 		 * The buffer contains our data block. Copy what we
1359 		 * need from it and loop.
1360 		 */
1361 		i = bsize - boff;
1362 		if (i > buflen) i = buflen;
1363 		memcpy(buf, &dnode_cache_buf[boff], i);
1364 		buf = ((char*) buf) + i;
1365 		offset += i;
1366 		buflen -= i;
1367 	}
1368 
1369 	return (0);
1370 }
1371 
1372 /*
1373  * Lookup a value in a microzap directory. Assumes that the zap
1374  * scratch buffer contains the directory contents.
1375  */
1376 static int
1377 mzap_lookup(const dnode_phys_t *dnode, const char *name, uint64_t *value)
1378 {
1379 	const mzap_phys_t *mz;
1380 	const mzap_ent_phys_t *mze;
1381 	size_t size;
1382 	int chunks, i;
1383 
1384 	/*
1385 	 * Microzap objects use exactly one block. Read the whole
1386 	 * thing.
1387 	 */
1388 	size = dnode->dn_datablkszsec * 512;
1389 
1390 	mz = (const mzap_phys_t *) zap_scratch;
1391 	chunks = size / MZAP_ENT_LEN - 1;
1392 
1393 	for (i = 0; i < chunks; i++) {
1394 		mze = &mz->mz_chunk[i];
1395 		if (!strcmp(mze->mze_name, name)) {
1396 			*value = mze->mze_value;
1397 			return (0);
1398 		}
1399 	}
1400 
1401 	return (ENOENT);
1402 }
1403 
1404 /*
1405  * Compare a name with a zap leaf entry. Return non-zero if the name
1406  * matches.
1407  */
1408 static int
1409 fzap_name_equal(const zap_leaf_t *zl, const zap_leaf_chunk_t *zc, const char *name)
1410 {
1411 	size_t namelen;
1412 	const zap_leaf_chunk_t *nc;
1413 	const char *p;
1414 
1415 	namelen = zc->l_entry.le_name_numints;
1416 
1417 	nc = &ZAP_LEAF_CHUNK(zl, zc->l_entry.le_name_chunk);
1418 	p = name;
1419 	while (namelen > 0) {
1420 		size_t len;
1421 		len = namelen;
1422 		if (len > ZAP_LEAF_ARRAY_BYTES)
1423 			len = ZAP_LEAF_ARRAY_BYTES;
1424 		if (memcmp(p, nc->l_array.la_array, len))
1425 			return (0);
1426 		p += len;
1427 		namelen -= len;
1428 		nc = &ZAP_LEAF_CHUNK(zl, nc->l_array.la_next);
1429 	}
1430 
1431 	return 1;
1432 }
1433 
1434 /*
1435  * Extract a uint64_t value from a zap leaf entry.
1436  */
1437 static uint64_t
1438 fzap_leaf_value(const zap_leaf_t *zl, const zap_leaf_chunk_t *zc)
1439 {
1440 	const zap_leaf_chunk_t *vc;
1441 	int i;
1442 	uint64_t value;
1443 	const uint8_t *p;
1444 
1445 	vc = &ZAP_LEAF_CHUNK(zl, zc->l_entry.le_value_chunk);
1446 	for (i = 0, value = 0, p = vc->l_array.la_array; i < 8; i++) {
1447 		value = (value << 8) | p[i];
1448 	}
1449 
1450 	return value;
1451 }
1452 
1453 static void
1454 stv(int len, void *addr, uint64_t value)
1455 {
1456 	switch (len) {
1457 	case 1:
1458 		*(uint8_t *)addr = value;
1459 		return;
1460 	case 2:
1461 		*(uint16_t *)addr = value;
1462 		return;
1463 	case 4:
1464 		*(uint32_t *)addr = value;
1465 		return;
1466 	case 8:
1467 		*(uint64_t *)addr = value;
1468 		return;
1469 	}
1470 }
1471 
1472 /*
1473  * Extract a array from a zap leaf entry.
1474  */
1475 static void
1476 fzap_leaf_array(const zap_leaf_t *zl, const zap_leaf_chunk_t *zc,
1477     uint64_t integer_size, uint64_t num_integers, void *buf)
1478 {
1479 	uint64_t array_int_len = zc->l_entry.le_value_intlen;
1480 	uint64_t value = 0;
1481 	uint64_t *u64 = buf;
1482 	char *p = buf;
1483 	int len = MIN(zc->l_entry.le_value_numints, num_integers);
1484 	int chunk = zc->l_entry.le_value_chunk;
1485 	int byten = 0;
1486 
1487 	if (integer_size == 8 && len == 1) {
1488 		*u64 = fzap_leaf_value(zl, zc);
1489 		return;
1490 	}
1491 
1492 	while (len > 0) {
1493 		struct zap_leaf_array *la = &ZAP_LEAF_CHUNK(zl, chunk).l_array;
1494 		int i;
1495 
1496 		ASSERT3U(chunk, <, ZAP_LEAF_NUMCHUNKS(zl));
1497 		for (i = 0; i < ZAP_LEAF_ARRAY_BYTES && len > 0; i++) {
1498 			value = (value << 8) | la->la_array[i];
1499 			byten++;
1500 			if (byten == array_int_len) {
1501 				stv(integer_size, p, value);
1502 				byten = 0;
1503 				len--;
1504 				if (len == 0)
1505 					return;
1506 				p += integer_size;
1507 			}
1508 		}
1509 		chunk = la->la_next;
1510 	}
1511 }
1512 
1513 /*
1514  * Lookup a value in a fatzap directory. Assumes that the zap scratch
1515  * buffer contains the directory header.
1516  */
1517 static int
1518 fzap_lookup(const spa_t *spa, const dnode_phys_t *dnode, const char *name,
1519     uint64_t integer_size, uint64_t num_integers, void *value)
1520 {
1521 	int bsize = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
1522 	zap_phys_t zh = *(zap_phys_t *) zap_scratch;
1523 	fat_zap_t z;
1524 	uint64_t *ptrtbl;
1525 	uint64_t hash;
1526 	int rc;
1527 
1528 	if (zh.zap_magic != ZAP_MAGIC)
1529 		return (EIO);
1530 
1531 	z.zap_block_shift = ilog2(bsize);
1532 	z.zap_phys = (zap_phys_t *) zap_scratch;
1533 
1534 	/*
1535 	 * Figure out where the pointer table is and read it in if necessary.
1536 	 */
1537 	if (zh.zap_ptrtbl.zt_blk) {
1538 		rc = dnode_read(spa, dnode, zh.zap_ptrtbl.zt_blk * bsize,
1539 			       zap_scratch, bsize);
1540 		if (rc)
1541 			return (rc);
1542 		ptrtbl = (uint64_t *) zap_scratch;
1543 	} else {
1544 		ptrtbl = &ZAP_EMBEDDED_PTRTBL_ENT(&z, 0);
1545 	}
1546 
1547 	hash = zap_hash(zh.zap_salt, name);
1548 
1549 	zap_leaf_t zl;
1550 	zl.l_bs = z.zap_block_shift;
1551 
1552 	off_t off = ptrtbl[hash >> (64 - zh.zap_ptrtbl.zt_shift)] << zl.l_bs;
1553 	zap_leaf_chunk_t *zc;
1554 
1555 	rc = dnode_read(spa, dnode, off, zap_scratch, bsize);
1556 	if (rc)
1557 		return (rc);
1558 
1559 	zl.l_phys = (zap_leaf_phys_t *) zap_scratch;
1560 
1561 	/*
1562 	 * Make sure this chunk matches our hash.
1563 	 */
1564 	if (zl.l_phys->l_hdr.lh_prefix_len > 0
1565 	    && zl.l_phys->l_hdr.lh_prefix
1566 	    != hash >> (64 - zl.l_phys->l_hdr.lh_prefix_len))
1567 		return (ENOENT);
1568 
1569 	/*
1570 	 * Hash within the chunk to find our entry.
1571 	 */
1572 	int shift = (64 - ZAP_LEAF_HASH_SHIFT(&zl) - zl.l_phys->l_hdr.lh_prefix_len);
1573 	int h = (hash >> shift) & ((1 << ZAP_LEAF_HASH_SHIFT(&zl)) - 1);
1574 	h = zl.l_phys->l_hash[h];
1575 	if (h == 0xffff)
1576 		return (ENOENT);
1577 	zc = &ZAP_LEAF_CHUNK(&zl, h);
1578 	while (zc->l_entry.le_hash != hash) {
1579 		if (zc->l_entry.le_next == 0xffff) {
1580 			zc = NULL;
1581 			break;
1582 		}
1583 		zc = &ZAP_LEAF_CHUNK(&zl, zc->l_entry.le_next);
1584 	}
1585 	if (fzap_name_equal(&zl, zc, name)) {
1586 		if (zc->l_entry.le_value_intlen * zc->l_entry.le_value_numints >
1587 		    integer_size * num_integers)
1588 			return (E2BIG);
1589 		fzap_leaf_array(&zl, zc, integer_size, num_integers, value);
1590 		return (0);
1591 	}
1592 
1593 	return (ENOENT);
1594 }
1595 
1596 /*
1597  * Lookup a name in a zap object and return its value as a uint64_t.
1598  */
1599 static int
1600 zap_lookup(const spa_t *spa, const dnode_phys_t *dnode, const char *name,
1601     uint64_t integer_size, uint64_t num_integers, void *value)
1602 {
1603 	int rc;
1604 	uint64_t zap_type;
1605 	size_t size = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
1606 
1607 	rc = dnode_read(spa, dnode, 0, zap_scratch, size);
1608 	if (rc)
1609 		return (rc);
1610 
1611 	zap_type = *(uint64_t *) zap_scratch;
1612 	if (zap_type == ZBT_MICRO)
1613 		return mzap_lookup(dnode, name, value);
1614 	else if (zap_type == ZBT_HEADER) {
1615 		return fzap_lookup(spa, dnode, name, integer_size,
1616 		    num_integers, value);
1617 	}
1618 	printf("ZFS: invalid zap_type=%d\n", (int)zap_type);
1619 	return (EIO);
1620 }
1621 
1622 /*
1623  * List a microzap directory. Assumes that the zap scratch buffer contains
1624  * the directory contents.
1625  */
1626 static int
1627 mzap_list(const dnode_phys_t *dnode, int (*callback)(const char *, uint64_t))
1628 {
1629 	const mzap_phys_t *mz;
1630 	const mzap_ent_phys_t *mze;
1631 	size_t size;
1632 	int chunks, i, rc;
1633 
1634 	/*
1635 	 * Microzap objects use exactly one block. Read the whole
1636 	 * thing.
1637 	 */
1638 	size = dnode->dn_datablkszsec * 512;
1639 	mz = (const mzap_phys_t *) zap_scratch;
1640 	chunks = size / MZAP_ENT_LEN - 1;
1641 
1642 	for (i = 0; i < chunks; i++) {
1643 		mze = &mz->mz_chunk[i];
1644 		if (mze->mze_name[0]) {
1645 			rc = callback(mze->mze_name, mze->mze_value);
1646 			if (rc != 0)
1647 				return (rc);
1648 		}
1649 	}
1650 
1651 	return (0);
1652 }
1653 
1654 /*
1655  * List a fatzap directory. Assumes that the zap scratch buffer contains
1656  * the directory header.
1657  */
1658 static int
1659 fzap_list(const spa_t *spa, const dnode_phys_t *dnode, int (*callback)(const char *, uint64_t))
1660 {
1661 	int bsize = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
1662 	zap_phys_t zh = *(zap_phys_t *) zap_scratch;
1663 	fat_zap_t z;
1664 	int i, j, rc;
1665 
1666 	if (zh.zap_magic != ZAP_MAGIC)
1667 		return (EIO);
1668 
1669 	z.zap_block_shift = ilog2(bsize);
1670 	z.zap_phys = (zap_phys_t *) zap_scratch;
1671 
1672 	/*
1673 	 * This assumes that the leaf blocks start at block 1. The
1674 	 * documentation isn't exactly clear on this.
1675 	 */
1676 	zap_leaf_t zl;
1677 	zl.l_bs = z.zap_block_shift;
1678 	for (i = 0; i < zh.zap_num_leafs; i++) {
1679 		off_t off = (i + 1) << zl.l_bs;
1680 		char name[256], *p;
1681 		uint64_t value;
1682 
1683 		if (dnode_read(spa, dnode, off, zap_scratch, bsize))
1684 			return (EIO);
1685 
1686 		zl.l_phys = (zap_leaf_phys_t *) zap_scratch;
1687 
1688 		for (j = 0; j < ZAP_LEAF_NUMCHUNKS(&zl); j++) {
1689 			zap_leaf_chunk_t *zc, *nc;
1690 			int namelen;
1691 
1692 			zc = &ZAP_LEAF_CHUNK(&zl, j);
1693 			if (zc->l_entry.le_type != ZAP_CHUNK_ENTRY)
1694 				continue;
1695 			namelen = zc->l_entry.le_name_numints;
1696 			if (namelen > sizeof(name))
1697 				namelen = sizeof(name);
1698 
1699 			/*
1700 			 * Paste the name back together.
1701 			 */
1702 			nc = &ZAP_LEAF_CHUNK(&zl, zc->l_entry.le_name_chunk);
1703 			p = name;
1704 			while (namelen > 0) {
1705 				int len;
1706 				len = namelen;
1707 				if (len > ZAP_LEAF_ARRAY_BYTES)
1708 					len = ZAP_LEAF_ARRAY_BYTES;
1709 				memcpy(p, nc->l_array.la_array, len);
1710 				p += len;
1711 				namelen -= len;
1712 				nc = &ZAP_LEAF_CHUNK(&zl, nc->l_array.la_next);
1713 			}
1714 
1715 			/*
1716 			 * Assume the first eight bytes of the value are
1717 			 * a uint64_t.
1718 			 */
1719 			value = fzap_leaf_value(&zl, zc);
1720 
1721 			//printf("%s 0x%jx\n", name, (uintmax_t)value);
1722 			rc = callback((const char *)name, value);
1723 			if (rc != 0)
1724 				return (rc);
1725 		}
1726 	}
1727 
1728 	return (0);
1729 }
1730 
1731 static int zfs_printf(const char *name, uint64_t value __unused)
1732 {
1733 
1734 	printf("%s\n", name);
1735 
1736 	return (0);
1737 }
1738 
1739 /*
1740  * List a zap directory.
1741  */
1742 static int
1743 zap_list(const spa_t *spa, const dnode_phys_t *dnode)
1744 {
1745 	uint64_t zap_type;
1746 	size_t size = dnode->dn_datablkszsec * 512;
1747 
1748 	if (dnode_read(spa, dnode, 0, zap_scratch, size))
1749 		return (EIO);
1750 
1751 	zap_type = *(uint64_t *) zap_scratch;
1752 	if (zap_type == ZBT_MICRO)
1753 		return mzap_list(dnode, zfs_printf);
1754 	else
1755 		return fzap_list(spa, dnode, zfs_printf);
1756 }
1757 
1758 static int
1759 objset_get_dnode(const spa_t *spa, const objset_phys_t *os, uint64_t objnum, dnode_phys_t *dnode)
1760 {
1761 	off_t offset;
1762 
1763 	offset = objnum * sizeof(dnode_phys_t);
1764 	return dnode_read(spa, &os->os_meta_dnode, offset,
1765 		dnode, sizeof(dnode_phys_t));
1766 }
1767 
1768 static int
1769 mzap_rlookup(const spa_t *spa, const dnode_phys_t *dnode, char *name, uint64_t value)
1770 {
1771 	const mzap_phys_t *mz;
1772 	const mzap_ent_phys_t *mze;
1773 	size_t size;
1774 	int chunks, i;
1775 
1776 	/*
1777 	 * Microzap objects use exactly one block. Read the whole
1778 	 * thing.
1779 	 */
1780 	size = dnode->dn_datablkszsec * 512;
1781 
1782 	mz = (const mzap_phys_t *) zap_scratch;
1783 	chunks = size / MZAP_ENT_LEN - 1;
1784 
1785 	for (i = 0; i < chunks; i++) {
1786 		mze = &mz->mz_chunk[i];
1787 		if (value == mze->mze_value) {
1788 			strcpy(name, mze->mze_name);
1789 			return (0);
1790 		}
1791 	}
1792 
1793 	return (ENOENT);
1794 }
1795 
1796 static void
1797 fzap_name_copy(const zap_leaf_t *zl, const zap_leaf_chunk_t *zc, char *name)
1798 {
1799 	size_t namelen;
1800 	const zap_leaf_chunk_t *nc;
1801 	char *p;
1802 
1803 	namelen = zc->l_entry.le_name_numints;
1804 
1805 	nc = &ZAP_LEAF_CHUNK(zl, zc->l_entry.le_name_chunk);
1806 	p = name;
1807 	while (namelen > 0) {
1808 		size_t len;
1809 		len = namelen;
1810 		if (len > ZAP_LEAF_ARRAY_BYTES)
1811 			len = ZAP_LEAF_ARRAY_BYTES;
1812 		memcpy(p, nc->l_array.la_array, len);
1813 		p += len;
1814 		namelen -= len;
1815 		nc = &ZAP_LEAF_CHUNK(zl, nc->l_array.la_next);
1816 	}
1817 
1818 	*p = '\0';
1819 }
1820 
1821 static int
1822 fzap_rlookup(const spa_t *spa, const dnode_phys_t *dnode, char *name, uint64_t value)
1823 {
1824 	int bsize = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
1825 	zap_phys_t zh = *(zap_phys_t *) zap_scratch;
1826 	fat_zap_t z;
1827 	int i, j;
1828 
1829 	if (zh.zap_magic != ZAP_MAGIC)
1830 		return (EIO);
1831 
1832 	z.zap_block_shift = ilog2(bsize);
1833 	z.zap_phys = (zap_phys_t *) zap_scratch;
1834 
1835 	/*
1836 	 * This assumes that the leaf blocks start at block 1. The
1837 	 * documentation isn't exactly clear on this.
1838 	 */
1839 	zap_leaf_t zl;
1840 	zl.l_bs = z.zap_block_shift;
1841 	for (i = 0; i < zh.zap_num_leafs; i++) {
1842 		off_t off = (i + 1) << zl.l_bs;
1843 
1844 		if (dnode_read(spa, dnode, off, zap_scratch, bsize))
1845 			return (EIO);
1846 
1847 		zl.l_phys = (zap_leaf_phys_t *) zap_scratch;
1848 
1849 		for (j = 0; j < ZAP_LEAF_NUMCHUNKS(&zl); j++) {
1850 			zap_leaf_chunk_t *zc;
1851 
1852 			zc = &ZAP_LEAF_CHUNK(&zl, j);
1853 			if (zc->l_entry.le_type != ZAP_CHUNK_ENTRY)
1854 				continue;
1855 			if (zc->l_entry.le_value_intlen != 8 ||
1856 			    zc->l_entry.le_value_numints != 1)
1857 				continue;
1858 
1859 			if (fzap_leaf_value(&zl, zc) == value) {
1860 				fzap_name_copy(&zl, zc, name);
1861 				return (0);
1862 			}
1863 		}
1864 	}
1865 
1866 	return (ENOENT);
1867 }
1868 
1869 static int
1870 zap_rlookup(const spa_t *spa, const dnode_phys_t *dnode, char *name, uint64_t value)
1871 {
1872 	int rc;
1873 	uint64_t zap_type;
1874 	size_t size = dnode->dn_datablkszsec * 512;
1875 
1876 	rc = dnode_read(spa, dnode, 0, zap_scratch, size);
1877 	if (rc)
1878 		return (rc);
1879 
1880 	zap_type = *(uint64_t *) zap_scratch;
1881 	if (zap_type == ZBT_MICRO)
1882 		return mzap_rlookup(spa, dnode, name, value);
1883 	else
1884 		return fzap_rlookup(spa, dnode, name, value);
1885 }
1886 
1887 static int
1888 zfs_rlookup(const spa_t *spa, uint64_t objnum, char *result)
1889 {
1890 	char name[256];
1891 	char component[256];
1892 	uint64_t dir_obj, parent_obj, child_dir_zapobj;
1893 	dnode_phys_t child_dir_zap, dataset, dir, parent;
1894 	dsl_dir_phys_t *dd;
1895 	dsl_dataset_phys_t *ds;
1896 	char *p;
1897 	int len;
1898 
1899 	p = &name[sizeof(name) - 1];
1900 	*p = '\0';
1901 
1902 	if (objset_get_dnode(spa, &spa->spa_mos, objnum, &dataset)) {
1903 		printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
1904 		return (EIO);
1905 	}
1906 	ds = (dsl_dataset_phys_t *)&dataset.dn_bonus;
1907 	dir_obj = ds->ds_dir_obj;
1908 
1909 	for (;;) {
1910 		if (objset_get_dnode(spa, &spa->spa_mos, dir_obj, &dir) != 0)
1911 			return (EIO);
1912 		dd = (dsl_dir_phys_t *)&dir.dn_bonus;
1913 
1914 		/* Actual loop condition. */
1915 		parent_obj  = dd->dd_parent_obj;
1916 		if (parent_obj == 0)
1917 			break;
1918 
1919 		if (objset_get_dnode(spa, &spa->spa_mos, parent_obj, &parent) != 0)
1920 			return (EIO);
1921 		dd = (dsl_dir_phys_t *)&parent.dn_bonus;
1922 		child_dir_zapobj = dd->dd_child_dir_zapobj;
1923 		if (objset_get_dnode(spa, &spa->spa_mos, child_dir_zapobj, &child_dir_zap) != 0)
1924 			return (EIO);
1925 		if (zap_rlookup(spa, &child_dir_zap, component, dir_obj) != 0)
1926 			return (EIO);
1927 
1928 		len = strlen(component);
1929 		p -= len;
1930 		memcpy(p, component, len);
1931 		--p;
1932 		*p = '/';
1933 
1934 		/* Actual loop iteration. */
1935 		dir_obj = parent_obj;
1936 	}
1937 
1938 	if (*p != '\0')
1939 		++p;
1940 	strcpy(result, p);
1941 
1942 	return (0);
1943 }
1944 
1945 static int
1946 zfs_lookup_dataset(const spa_t *spa, const char *name, uint64_t *objnum)
1947 {
1948 	char element[256];
1949 	uint64_t dir_obj, child_dir_zapobj;
1950 	dnode_phys_t child_dir_zap, dir;
1951 	dsl_dir_phys_t *dd;
1952 	const char *p, *q;
1953 
1954 	if (objset_get_dnode(spa, &spa->spa_mos, DMU_POOL_DIRECTORY_OBJECT, &dir))
1955 		return (EIO);
1956 	if (zap_lookup(spa, &dir, DMU_POOL_ROOT_DATASET, sizeof (dir_obj),
1957 	    1, &dir_obj))
1958 		return (EIO);
1959 
1960 	p = name;
1961 	for (;;) {
1962 		if (objset_get_dnode(spa, &spa->spa_mos, dir_obj, &dir))
1963 			return (EIO);
1964 		dd = (dsl_dir_phys_t *)&dir.dn_bonus;
1965 
1966 		while (*p == '/')
1967 			p++;
1968 		/* Actual loop condition #1. */
1969 		if (*p == '\0')
1970 			break;
1971 
1972 		q = strchr(p, '/');
1973 		if (q) {
1974 			memcpy(element, p, q - p);
1975 			element[q - p] = '\0';
1976 			p = q + 1;
1977 		} else {
1978 			strcpy(element, p);
1979 			p += strlen(p);
1980 		}
1981 
1982 		child_dir_zapobj = dd->dd_child_dir_zapobj;
1983 		if (objset_get_dnode(spa, &spa->spa_mos, child_dir_zapobj, &child_dir_zap) != 0)
1984 			return (EIO);
1985 
1986 		/* Actual loop condition #2. */
1987 		if (zap_lookup(spa, &child_dir_zap, element, sizeof (dir_obj),
1988 		    1, &dir_obj) != 0)
1989 			return (ENOENT);
1990 	}
1991 
1992 	*objnum = dd->dd_head_dataset_obj;
1993 	return (0);
1994 }
1995 
1996 #ifndef BOOT2
1997 static int
1998 zfs_list_dataset(const spa_t *spa, uint64_t objnum/*, int pos, char *entry*/)
1999 {
2000 	uint64_t dir_obj, child_dir_zapobj;
2001 	dnode_phys_t child_dir_zap, dir, dataset;
2002 	dsl_dataset_phys_t *ds;
2003 	dsl_dir_phys_t *dd;
2004 
2005 	if (objset_get_dnode(spa, &spa->spa_mos, objnum, &dataset)) {
2006 		printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
2007 		return (EIO);
2008 	}
2009 	ds = (dsl_dataset_phys_t *) &dataset.dn_bonus;
2010 	dir_obj = ds->ds_dir_obj;
2011 
2012 	if (objset_get_dnode(spa, &spa->spa_mos, dir_obj, &dir)) {
2013 		printf("ZFS: can't find dirobj %ju\n", (uintmax_t)dir_obj);
2014 		return (EIO);
2015 	}
2016 	dd = (dsl_dir_phys_t *)&dir.dn_bonus;
2017 
2018 	child_dir_zapobj = dd->dd_child_dir_zapobj;
2019 	if (objset_get_dnode(spa, &spa->spa_mos, child_dir_zapobj, &child_dir_zap) != 0) {
2020 		printf("ZFS: can't find child zap %ju\n", (uintmax_t)dir_obj);
2021 		return (EIO);
2022 	}
2023 
2024 	return (zap_list(spa, &child_dir_zap) != 0);
2025 }
2026 
2027 int
2028 zfs_callback_dataset(const spa_t *spa, uint64_t objnum, int (*callback)(const char *, uint64_t))
2029 {
2030 	uint64_t dir_obj, child_dir_zapobj, zap_type;
2031 	dnode_phys_t child_dir_zap, dir, dataset;
2032 	dsl_dataset_phys_t *ds;
2033 	dsl_dir_phys_t *dd;
2034 	int err;
2035 
2036 	err = objset_get_dnode(spa, &spa->spa_mos, objnum, &dataset);
2037 	if (err != 0) {
2038 		printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
2039 		return (err);
2040 	}
2041 	ds = (dsl_dataset_phys_t *) &dataset.dn_bonus;
2042 	dir_obj = ds->ds_dir_obj;
2043 
2044 	err = objset_get_dnode(spa, &spa->spa_mos, dir_obj, &dir);
2045 	if (err != 0) {
2046 		printf("ZFS: can't find dirobj %ju\n", (uintmax_t)dir_obj);
2047 		return (err);
2048 	}
2049 	dd = (dsl_dir_phys_t *)&dir.dn_bonus;
2050 
2051 	child_dir_zapobj = dd->dd_child_dir_zapobj;
2052 	err = objset_get_dnode(spa, &spa->spa_mos, child_dir_zapobj, &child_dir_zap);
2053 	if (err != 0) {
2054 		printf("ZFS: can't find child zap %ju\n", (uintmax_t)dir_obj);
2055 		return (err);
2056 	}
2057 
2058 	err = dnode_read(spa, &child_dir_zap, 0, zap_scratch, child_dir_zap.dn_datablkszsec * 512);
2059 	if (err != 0)
2060 		return (err);
2061 
2062 	zap_type = *(uint64_t *) zap_scratch;
2063 	if (zap_type == ZBT_MICRO)
2064 		return mzap_list(&child_dir_zap, callback);
2065 	else
2066 		return fzap_list(spa, &child_dir_zap, callback);
2067 }
2068 #endif
2069 
2070 /*
2071  * Find the object set given the object number of its dataset object
2072  * and return its details in *objset
2073  */
2074 static int
2075 zfs_mount_dataset(const spa_t *spa, uint64_t objnum, objset_phys_t *objset)
2076 {
2077 	dnode_phys_t dataset;
2078 	dsl_dataset_phys_t *ds;
2079 
2080 	if (objset_get_dnode(spa, &spa->spa_mos, objnum, &dataset)) {
2081 		printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
2082 		return (EIO);
2083 	}
2084 
2085 	ds = (dsl_dataset_phys_t *) &dataset.dn_bonus;
2086 	if (zio_read(spa, &ds->ds_bp, objset)) {
2087 		printf("ZFS: can't read object set for dataset %ju\n",
2088 		    (uintmax_t)objnum);
2089 		return (EIO);
2090 	}
2091 
2092 	return (0);
2093 }
2094 
2095 /*
2096  * Find the object set pointed to by the BOOTFS property or the root
2097  * dataset if there is none and return its details in *objset
2098  */
2099 static int
2100 zfs_get_root(const spa_t *spa, uint64_t *objid)
2101 {
2102 	dnode_phys_t dir, propdir;
2103 	uint64_t props, bootfs, root;
2104 
2105 	*objid = 0;
2106 
2107 	/*
2108 	 * Start with the MOS directory object.
2109 	 */
2110 	if (objset_get_dnode(spa, &spa->spa_mos, DMU_POOL_DIRECTORY_OBJECT, &dir)) {
2111 		printf("ZFS: can't read MOS object directory\n");
2112 		return (EIO);
2113 	}
2114 
2115 	/*
2116 	 * Lookup the pool_props and see if we can find a bootfs.
2117 	 */
2118 	if (zap_lookup(spa, &dir, DMU_POOL_PROPS, sizeof (props), 1, &props) == 0
2119 	     && objset_get_dnode(spa, &spa->spa_mos, props, &propdir) == 0
2120 	     && zap_lookup(spa, &propdir, "bootfs", sizeof (bootfs), 1, &bootfs) == 0
2121 	     && bootfs != 0)
2122 	{
2123 		*objid = bootfs;
2124 		return (0);
2125 	}
2126 	/*
2127 	 * Lookup the root dataset directory
2128 	 */
2129 	if (zap_lookup(spa, &dir, DMU_POOL_ROOT_DATASET, sizeof (root), 1, &root)
2130 	    || objset_get_dnode(spa, &spa->spa_mos, root, &dir)) {
2131 		printf("ZFS: can't find root dsl_dir\n");
2132 		return (EIO);
2133 	}
2134 
2135 	/*
2136 	 * Use the information from the dataset directory's bonus buffer
2137 	 * to find the dataset object and from that the object set itself.
2138 	 */
2139 	dsl_dir_phys_t *dd = (dsl_dir_phys_t *) &dir.dn_bonus;
2140 	*objid = dd->dd_head_dataset_obj;
2141 	return (0);
2142 }
2143 
2144 static int
2145 zfs_mount(const spa_t *spa, uint64_t rootobj, struct zfsmount *mount)
2146 {
2147 
2148 	mount->spa = spa;
2149 
2150 	/*
2151 	 * Find the root object set if not explicitly provided
2152 	 */
2153 	if (rootobj == 0 && zfs_get_root(spa, &rootobj)) {
2154 		printf("ZFS: can't find root filesystem\n");
2155 		return (EIO);
2156 	}
2157 
2158 	if (zfs_mount_dataset(spa, rootobj, &mount->objset)) {
2159 		printf("ZFS: can't open root filesystem\n");
2160 		return (EIO);
2161 	}
2162 
2163 	mount->rootobj = rootobj;
2164 
2165 	return (0);
2166 }
2167 
2168 /*
2169  * callback function for feature name checks.
2170  */
2171 static int
2172 check_feature(const char *name, uint64_t value)
2173 {
2174 	int i;
2175 
2176 	if (value == 0)
2177 		return (0);
2178 	if (name[0] == '\0')
2179 		return (0);
2180 
2181 	for (i = 0; features_for_read[i] != NULL; i++) {
2182 		if (strcmp(name, features_for_read[i]) == 0)
2183 			return (0);
2184 	}
2185 	printf("ZFS: unsupported feature: %s\n", name);
2186 	return (EIO);
2187 }
2188 
2189 /*
2190  * Checks whether the MOS features that are active are supported.
2191  */
2192 static int
2193 check_mos_features(const spa_t *spa)
2194 {
2195 	dnode_phys_t dir;
2196 	uint64_t objnum, zap_type;
2197 	size_t size;
2198 	int rc;
2199 
2200 	if ((rc = objset_get_dnode(spa, &spa->spa_mos, DMU_OT_OBJECT_DIRECTORY,
2201 	    &dir)) != 0)
2202 		return (rc);
2203 	if ((rc = zap_lookup(spa, &dir, DMU_POOL_FEATURES_FOR_READ,
2204 	    sizeof (objnum), 1, &objnum)) != 0) {
2205 		/*
2206 		 * It is older pool without features. As we have already
2207 		 * tested the label, just return without raising the error.
2208 		 */
2209 		return (0);
2210 	}
2211 
2212 	if ((rc = objset_get_dnode(spa, &spa->spa_mos, objnum, &dir)) != 0)
2213 		return (rc);
2214 
2215 	if (dir.dn_type != DMU_OTN_ZAP_METADATA)
2216 		return (EIO);
2217 
2218 	size = dir.dn_datablkszsec * 512;
2219 	if (dnode_read(spa, &dir, 0, zap_scratch, size))
2220 		return (EIO);
2221 
2222 	zap_type = *(uint64_t *) zap_scratch;
2223 	if (zap_type == ZBT_MICRO)
2224 		rc = mzap_list(&dir, check_feature);
2225 	else
2226 		rc = fzap_list(spa, &dir, check_feature);
2227 
2228 	return (rc);
2229 }
2230 
2231 static int
2232 zfs_spa_init(spa_t *spa)
2233 {
2234 	dnode_phys_t dir;
2235 	int rc;
2236 
2237 	if (zio_read(spa, &spa->spa_uberblock.ub_rootbp, &spa->spa_mos)) {
2238 		printf("ZFS: can't read MOS of pool %s\n", spa->spa_name);
2239 		return (EIO);
2240 	}
2241 	if (spa->spa_mos.os_type != DMU_OST_META) {
2242 		printf("ZFS: corrupted MOS of pool %s\n", spa->spa_name);
2243 		return (EIO);
2244 	}
2245 
2246 	if (objset_get_dnode(spa, &spa->spa_mos, DMU_POOL_DIRECTORY_OBJECT,
2247 	    &dir)) {
2248 		printf("ZFS: failed to read pool %s directory object\n",
2249 		    spa->spa_name);
2250 		return (EIO);
2251 	}
2252 	/* this is allowed to fail, older pools do not have salt */
2253 	rc = zap_lookup(spa, &dir, DMU_POOL_CHECKSUM_SALT, 1,
2254 	    sizeof (spa->spa_cksum_salt.zcs_bytes),
2255 	    spa->spa_cksum_salt.zcs_bytes);
2256 
2257 	rc = check_mos_features(spa);
2258 	if (rc != 0) {
2259 		printf("ZFS: pool %s is not supported\n", spa->spa_name);
2260 	}
2261 
2262 	return (rc);
2263 }
2264 
2265 static int
2266 zfs_dnode_stat(const spa_t *spa, dnode_phys_t *dn, struct stat *sb)
2267 {
2268 
2269 	if (dn->dn_bonustype != DMU_OT_SA) {
2270 		znode_phys_t *zp = (znode_phys_t *)dn->dn_bonus;
2271 
2272 		sb->st_mode = zp->zp_mode;
2273 		sb->st_uid = zp->zp_uid;
2274 		sb->st_gid = zp->zp_gid;
2275 		sb->st_size = zp->zp_size;
2276 	} else {
2277 		sa_hdr_phys_t *sahdrp;
2278 		int hdrsize;
2279 		size_t size = 0;
2280 		void *buf = NULL;
2281 
2282 		if (dn->dn_bonuslen != 0)
2283 			sahdrp = (sa_hdr_phys_t *)DN_BONUS(dn);
2284 		else {
2285 			if ((dn->dn_flags & DNODE_FLAG_SPILL_BLKPTR) != 0) {
2286 				blkptr_t *bp = DN_SPILL_BLKPTR(dn);
2287 				int error;
2288 
2289 				size = BP_GET_LSIZE(bp);
2290 				buf = zfs_alloc(size);
2291 				error = zio_read(spa, bp, buf);
2292 				if (error != 0) {
2293 					zfs_free(buf, size);
2294 					return (error);
2295 				}
2296 				sahdrp = buf;
2297 			} else {
2298 				return (EIO);
2299 			}
2300 		}
2301 		hdrsize = SA_HDR_SIZE(sahdrp);
2302 		sb->st_mode = *(uint64_t *)((char *)sahdrp + hdrsize +
2303 		    SA_MODE_OFFSET);
2304 		sb->st_uid = *(uint64_t *)((char *)sahdrp + hdrsize +
2305 		    SA_UID_OFFSET);
2306 		sb->st_gid = *(uint64_t *)((char *)sahdrp + hdrsize +
2307 		    SA_GID_OFFSET);
2308 		sb->st_size = *(uint64_t *)((char *)sahdrp + hdrsize +
2309 		    SA_SIZE_OFFSET);
2310 		if (buf != NULL)
2311 			zfs_free(buf, size);
2312 	}
2313 
2314 	return (0);
2315 }
2316 
2317 static int
2318 zfs_dnode_readlink(const spa_t *spa, dnode_phys_t *dn, char *path, size_t psize)
2319 {
2320 	int rc = 0;
2321 
2322 	if (dn->dn_bonustype == DMU_OT_SA) {
2323 		sa_hdr_phys_t *sahdrp = NULL;
2324 		size_t size = 0;
2325 		void *buf = NULL;
2326 		int hdrsize;
2327 		char *p;
2328 
2329 		if (dn->dn_bonuslen != 0)
2330 			sahdrp = (sa_hdr_phys_t *)DN_BONUS(dn);
2331 		else {
2332 			blkptr_t *bp;
2333 
2334 			if ((dn->dn_flags & DNODE_FLAG_SPILL_BLKPTR) == 0)
2335 				return (EIO);
2336 			bp = DN_SPILL_BLKPTR(dn);
2337 
2338 			size = BP_GET_LSIZE(bp);
2339 			buf = zfs_alloc(size);
2340 			rc = zio_read(spa, bp, buf);
2341 			if (rc != 0) {
2342 				zfs_free(buf, size);
2343 				return (rc);
2344 			}
2345 			sahdrp = buf;
2346 		}
2347 		hdrsize = SA_HDR_SIZE(sahdrp);
2348 		p = (char *)((uintptr_t)sahdrp + hdrsize + SA_SYMLINK_OFFSET);
2349 		memcpy(path, p, psize);
2350 		if (buf != NULL)
2351 			zfs_free(buf, size);
2352 		return (0);
2353 	}
2354 	/*
2355 	 * Second test is purely to silence bogus compiler
2356 	 * warning about accessing past the end of dn_bonus.
2357 	 */
2358 	if (psize + sizeof(znode_phys_t) <= dn->dn_bonuslen &&
2359 	    sizeof(znode_phys_t) <= sizeof(dn->dn_bonus)) {
2360 		memcpy(path, &dn->dn_bonus[sizeof(znode_phys_t)], psize);
2361 	} else {
2362 		rc = dnode_read(spa, dn, 0, path, psize);
2363 	}
2364 	return (rc);
2365 }
2366 
2367 struct obj_list {
2368 	uint64_t		objnum;
2369 	STAILQ_ENTRY(obj_list)	entry;
2370 };
2371 
2372 /*
2373  * Lookup a file and return its dnode.
2374  */
2375 static int
2376 zfs_lookup(const struct zfsmount *mount, const char *upath, dnode_phys_t *dnode)
2377 {
2378 	int rc;
2379 	uint64_t objnum;
2380 	const spa_t *spa;
2381 	dnode_phys_t dn;
2382 	const char *p, *q;
2383 	char element[256];
2384 	char path[1024];
2385 	int symlinks_followed = 0;
2386 	struct stat sb;
2387 	struct obj_list *entry, *tentry;
2388 	STAILQ_HEAD(, obj_list) on_cache = STAILQ_HEAD_INITIALIZER(on_cache);
2389 
2390 	spa = mount->spa;
2391 	if (mount->objset.os_type != DMU_OST_ZFS) {
2392 		printf("ZFS: unexpected object set type %ju\n",
2393 		    (uintmax_t)mount->objset.os_type);
2394 		return (EIO);
2395 	}
2396 
2397 	if ((entry = malloc(sizeof(struct obj_list))) == NULL)
2398 		return (ENOMEM);
2399 
2400 	/*
2401 	 * Get the root directory dnode.
2402 	 */
2403 	rc = objset_get_dnode(spa, &mount->objset, MASTER_NODE_OBJ, &dn);
2404 	if (rc) {
2405 		free(entry);
2406 		return (rc);
2407 	}
2408 
2409 	rc = zap_lookup(spa, &dn, ZFS_ROOT_OBJ, sizeof (objnum), 1, &objnum);
2410 	if (rc) {
2411 		free(entry);
2412 		return (rc);
2413 	}
2414 	entry->objnum = objnum;
2415 	STAILQ_INSERT_HEAD(&on_cache, entry, entry);
2416 
2417 	rc = objset_get_dnode(spa, &mount->objset, objnum, &dn);
2418 	if (rc != 0)
2419 		goto done;
2420 
2421 	p = upath;
2422 	while (p && *p) {
2423 		rc = objset_get_dnode(spa, &mount->objset, objnum, &dn);
2424 		if (rc != 0)
2425 			goto done;
2426 
2427 		while (*p == '/')
2428 			p++;
2429 		if (*p == '\0')
2430 			break;
2431 		q = p;
2432 		while (*q != '\0' && *q != '/')
2433 			q++;
2434 
2435 		/* skip dot */
2436 		if (p + 1 == q && p[0] == '.') {
2437 			p++;
2438 			continue;
2439 		}
2440 		/* double dot */
2441 		if (p + 2 == q && p[0] == '.' && p[1] == '.') {
2442 			p += 2;
2443 			if (STAILQ_FIRST(&on_cache) ==
2444 			    STAILQ_LAST(&on_cache, obj_list, entry)) {
2445 				rc = ENOENT;
2446 				goto done;
2447 			}
2448 			entry = STAILQ_FIRST(&on_cache);
2449 			STAILQ_REMOVE_HEAD(&on_cache, entry);
2450 			free(entry);
2451 			objnum = (STAILQ_FIRST(&on_cache))->objnum;
2452 			continue;
2453 		}
2454 		if (q - p + 1 > sizeof(element)) {
2455 			rc = ENAMETOOLONG;
2456 			goto done;
2457 		}
2458 		memcpy(element, p, q - p);
2459 		element[q - p] = 0;
2460 		p = q;
2461 
2462 		if ((rc = zfs_dnode_stat(spa, &dn, &sb)) != 0)
2463 			goto done;
2464 		if (!S_ISDIR(sb.st_mode)) {
2465 			rc = ENOTDIR;
2466 			goto done;
2467 		}
2468 
2469 		rc = zap_lookup(spa, &dn, element, sizeof (objnum), 1, &objnum);
2470 		if (rc)
2471 			goto done;
2472 		objnum = ZFS_DIRENT_OBJ(objnum);
2473 
2474 		if ((entry = malloc(sizeof(struct obj_list))) == NULL) {
2475 			rc = ENOMEM;
2476 			goto done;
2477 		}
2478 		entry->objnum = objnum;
2479 		STAILQ_INSERT_HEAD(&on_cache, entry, entry);
2480 		rc = objset_get_dnode(spa, &mount->objset, objnum, &dn);
2481 		if (rc)
2482 			goto done;
2483 
2484 		/*
2485 		 * Check for symlink.
2486 		 */
2487 		rc = zfs_dnode_stat(spa, &dn, &sb);
2488 		if (rc)
2489 			goto done;
2490 		if (S_ISLNK(sb.st_mode)) {
2491 			if (symlinks_followed > 10) {
2492 				rc = EMLINK;
2493 				goto done;
2494 			}
2495 			symlinks_followed++;
2496 
2497 			/*
2498 			 * Read the link value and copy the tail of our
2499 			 * current path onto the end.
2500 			 */
2501 			if (sb.st_size + strlen(p) + 1 > sizeof(path)) {
2502 				rc = ENAMETOOLONG;
2503 				goto done;
2504 			}
2505 			strcpy(&path[sb.st_size], p);
2506 
2507 			rc = zfs_dnode_readlink(spa, &dn, path, sb.st_size);
2508 			if (rc != 0)
2509 				goto done;
2510 
2511 			/*
2512 			 * Restart with the new path, starting either at
2513 			 * the root or at the parent depending whether or
2514 			 * not the link is relative.
2515 			 */
2516 			p = path;
2517 			if (*p == '/') {
2518 				while (STAILQ_FIRST(&on_cache) !=
2519 				    STAILQ_LAST(&on_cache, obj_list, entry)) {
2520 					entry = STAILQ_FIRST(&on_cache);
2521 					STAILQ_REMOVE_HEAD(&on_cache, entry);
2522 					free(entry);
2523 				}
2524 			} else {
2525 				entry = STAILQ_FIRST(&on_cache);
2526 				STAILQ_REMOVE_HEAD(&on_cache, entry);
2527 				free(entry);
2528 			}
2529 			objnum = (STAILQ_FIRST(&on_cache))->objnum;
2530 		}
2531 	}
2532 
2533 	*dnode = dn;
2534 done:
2535 	STAILQ_FOREACH_SAFE(entry, &on_cache, entry, tentry)
2536 		free(entry);
2537 	return (rc);
2538 }
2539