xref: /netbsd-src/external/cddl/osnet/dist/lib/libzfs/common/libzfs_changelist.c (revision 3227e6cf668bd374971740bd6660f43cee4417ac)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  *
26  * Portions Copyright 2007 Ramprakash Jelari
27  * Copyright (c) 2011 Pawel Jakub Dawidek <pawel@dawidek.net>.
28  * All rights reserved.
29  * Copyright (c) 2014, 2015 by Delphix. All rights reserved.
30  * Copyright 2016 Igor Kozhukhov <ikozhukhov@gmail.com>
31  */
32 
33 #include <libintl.h>
34 #include <libuutil.h>
35 #include <stddef.h>
36 #include <stdlib.h>
37 #include <string.h>
38 #include <unistd.h>
39 #include <zone.h>
40 
41 #include <libzfs.h>
42 
43 #include "libzfs_impl.h"
44 
45 /*
46  * Structure to keep track of dataset state.  Before changing the 'sharenfs' or
47  * 'mountpoint' property, we record whether the filesystem was previously
48  * mounted/shared.  This prior state dictates whether we remount/reshare the
49  * dataset after the property has been changed.
50  *
51  * The interface consists of the following sequence of functions:
52  *
53  * 	changelist_gather()
54  * 	changelist_prefix()
55  * 	< change property >
56  * 	changelist_postfix()
57  * 	changelist_free()
58  *
59  * Other interfaces:
60  *
61  * changelist_remove() - remove a node from a gathered list
62  * changelist_rename() - renames all datasets appropriately when doing a rename
63  * changelist_unshare() - unshares all the nodes in a given changelist
64  * changelist_haszonedchild() - check if there is any child exported to
65  *				a local zone
66  */
67 typedef struct prop_changenode {
68 	zfs_handle_t		*cn_handle;
69 	int			cn_shared;
70 	int			cn_mounted;
71 	int			cn_zoned;
72 	boolean_t		cn_needpost;	/* is postfix() needed? */
73 	uu_list_node_t		cn_listnode;
74 } prop_changenode_t;
75 
76 struct prop_changelist {
77 	zfs_prop_t		cl_prop;
78 	zfs_prop_t		cl_realprop;
79 	zfs_prop_t		cl_shareprop;  /* used with sharenfs/sharesmb */
80 	uu_list_pool_t		*cl_pool;
81 	uu_list_t		*cl_list;
82 	boolean_t		cl_waslegacy;
83 	boolean_t		cl_allchildren;
84 	boolean_t		cl_alldependents;
85 	int			cl_mflags;	/* Mount flags */
86 	int			cl_gflags;	/* Gather request flags */
87 	boolean_t		cl_haszonedchild;
88 	boolean_t		cl_sorted;
89 };
90 
91 /*
92  * If the property is 'mountpoint', go through and unmount filesystems as
93  * necessary.  We don't do the same for 'sharenfs', because we can just re-share
94  * with different options without interrupting service. We do handle 'sharesmb'
95  * since there may be old resource names that need to be removed.
96  */
97 int
changelist_prefix(prop_changelist_t * clp)98 changelist_prefix(prop_changelist_t *clp)
99 {
100 	prop_changenode_t *cn;
101 	int ret = 0;
102 
103 	if (clp->cl_prop != ZFS_PROP_MOUNTPOINT &&
104 	    clp->cl_prop != ZFS_PROP_SHARESMB)
105 		return (0);
106 
107 	for (cn = uu_list_first(clp->cl_list); cn != NULL;
108 	    cn = uu_list_next(clp->cl_list, cn)) {
109 
110 		/* if a previous loop failed, set the remaining to false */
111 		if (ret == -1) {
112 			cn->cn_needpost = B_FALSE;
113 			continue;
114 		}
115 
116 		/*
117 		 * If we are in the global zone, but this dataset is exported
118 		 * to a local zone, do nothing.
119 		 */
120 		if (getzoneid() == GLOBAL_ZONEID && cn->cn_zoned)
121 			continue;
122 
123 		if (!ZFS_IS_VOLUME(cn->cn_handle)) {
124 			/*
125 			 * Do the property specific processing.
126 			 */
127 			switch (clp->cl_prop) {
128 			case ZFS_PROP_MOUNTPOINT:
129 				if (clp->cl_gflags & CL_GATHER_DONT_UNMOUNT)
130 					break;
131 				if (zfs_unmount(cn->cn_handle, NULL,
132 				    clp->cl_mflags) != 0) {
133 					ret = -1;
134 					cn->cn_needpost = B_FALSE;
135 				}
136 				break;
137 			case ZFS_PROP_SHARESMB:
138 				(void) zfs_unshare_smb(cn->cn_handle, NULL);
139 				break;
140 
141 			default:
142 				break;
143 			}
144 		}
145 	}
146 
147 	if (ret == -1)
148 		(void) changelist_postfix(clp);
149 
150 	return (ret);
151 }
152 
153 /*
154  * If the property is 'mountpoint' or 'sharenfs', go through and remount and/or
155  * reshare the filesystems as necessary.  In changelist_gather() we recorded
156  * whether the filesystem was previously shared or mounted.  The action we take
157  * depends on the previous state, and whether the value was previously 'legacy'.
158  * For non-legacy properties, we only remount/reshare the filesystem if it was
159  * previously mounted/shared.  Otherwise, we always remount/reshare the
160  * filesystem.
161  */
162 int
changelist_postfix(prop_changelist_t * clp)163 changelist_postfix(prop_changelist_t *clp)
164 {
165 	prop_changenode_t *cn;
166 	char shareopts[ZFS_MAXPROPLEN];
167 	int errors = 0;
168 	libzfs_handle_t *hdl;
169 
170 	/*
171 	 * If we're changing the mountpoint, attempt to destroy the underlying
172 	 * mountpoint.  All other datasets will have inherited from this dataset
173 	 * (in which case their mountpoints exist in the filesystem in the new
174 	 * location), or have explicit mountpoints set (in which case they won't
175 	 * be in the changelist).
176 	 */
177 	if ((cn = uu_list_last(clp->cl_list)) == NULL)
178 		return (0);
179 
180 	if (clp->cl_prop == ZFS_PROP_MOUNTPOINT &&
181 	    !(clp->cl_gflags & CL_GATHER_DONT_UNMOUNT)) {
182 		remove_mountpoint(cn->cn_handle);
183 	}
184 
185 	/*
186 	 * It is possible that the changelist_prefix() used libshare
187 	 * to unshare some entries. Since libshare caches data, an
188 	 * attempt to reshare during postfix can fail unless libshare
189 	 * is uninitialized here so that it will reinitialize later.
190 	 */
191 	if (cn->cn_handle != NULL) {
192 		hdl = cn->cn_handle->zfs_hdl;
193 		assert(hdl != NULL);
194 		zfs_uninit_libshare(hdl);
195 	}
196 
197 	/*
198 	 * We walk the datasets in reverse, because we want to mount any parent
199 	 * datasets before mounting the children.  We walk all datasets even if
200 	 * there are errors.
201 	 */
202 	for (cn = uu_list_last(clp->cl_list); cn != NULL;
203 	    cn = uu_list_prev(clp->cl_list, cn)) {
204 
205 		boolean_t sharenfs;
206 		boolean_t sharesmb;
207 		boolean_t mounted;
208 
209 		/*
210 		 * If we are in the global zone, but this dataset is exported
211 		 * to a local zone, do nothing.
212 		 */
213 		if (getzoneid() == GLOBAL_ZONEID && cn->cn_zoned)
214 			continue;
215 
216 		/* Only do post-processing if it's required */
217 		if (!cn->cn_needpost)
218 			continue;
219 		cn->cn_needpost = B_FALSE;
220 
221 		zfs_refresh_properties(cn->cn_handle);
222 
223 		if (ZFS_IS_VOLUME(cn->cn_handle))
224 			continue;
225 
226 		/*
227 		 * Remount if previously mounted or mountpoint was legacy,
228 		 * or sharenfs or sharesmb  property is set.
229 		 */
230 		sharenfs = ((zfs_prop_get(cn->cn_handle, ZFS_PROP_SHARENFS,
231 		    shareopts, sizeof (shareopts), NULL, NULL, 0,
232 		    B_FALSE) == 0) && (strcmp(shareopts, "off") != 0));
233 
234 		sharesmb = ((zfs_prop_get(cn->cn_handle, ZFS_PROP_SHARESMB,
235 		    shareopts, sizeof (shareopts), NULL, NULL, 0,
236 		    B_FALSE) == 0) && (strcmp(shareopts, "off") != 0));
237 
238 		mounted = (clp->cl_gflags & CL_GATHER_DONT_UNMOUNT) ||
239 		    zfs_is_mounted(cn->cn_handle, NULL);
240 
241 		if (!mounted && (cn->cn_mounted ||
242 		    ((sharenfs || sharesmb || clp->cl_waslegacy) &&
243 		    (zfs_prop_get_int(cn->cn_handle,
244 		    ZFS_PROP_CANMOUNT) == ZFS_CANMOUNT_ON)))) {
245 
246 			if (zfs_mount(cn->cn_handle, NULL, 0) != 0)
247 				errors++;
248 			else
249 				mounted = TRUE;
250 		}
251 
252 		/*
253 		 * If the file system is mounted we always re-share even
254 		 * if the filesystem is currently shared, so that we can
255 		 * adopt any new options.
256 		 */
257 		if (sharenfs && mounted)
258 			errors += zfs_share_nfs(cn->cn_handle);
259 		else if (cn->cn_shared || clp->cl_waslegacy)
260 			errors += zfs_unshare_nfs(cn->cn_handle, NULL);
261 		if (sharesmb && mounted)
262 			errors += zfs_share_smb(cn->cn_handle);
263 		else if (cn->cn_shared || clp->cl_waslegacy)
264 			errors += zfs_unshare_smb(cn->cn_handle, NULL);
265 	}
266 
267 	return (errors ? -1 : 0);
268 }
269 
270 /*
271  * Is this "dataset" a child of "parent"?
272  */
273 boolean_t
isa_child_of(const char * dataset,const char * parent)274 isa_child_of(const char *dataset, const char *parent)
275 {
276 	int len;
277 
278 	len = strlen(parent);
279 
280 	if (strncmp(dataset, parent, len) == 0 &&
281 	    (dataset[len] == '@' || dataset[len] == '/' ||
282 	    dataset[len] == '\0'))
283 		return (B_TRUE);
284 	else
285 		return (B_FALSE);
286 
287 }
288 
289 /*
290  * If we rename a filesystem, child filesystem handles are no longer valid
291  * since we identify each dataset by its name in the ZFS namespace.  As a
292  * result, we have to go through and fix up all the names appropriately.  We
293  * could do this automatically if libzfs kept track of all open handles, but
294  * this is a lot less work.
295  */
296 void
changelist_rename(prop_changelist_t * clp,const char * src,const char * dst)297 changelist_rename(prop_changelist_t *clp, const char *src, const char *dst)
298 {
299 	prop_changenode_t *cn;
300 	char newname[ZFS_MAX_DATASET_NAME_LEN];
301 
302 	for (cn = uu_list_first(clp->cl_list); cn != NULL;
303 	    cn = uu_list_next(clp->cl_list, cn)) {
304 		/*
305 		 * Do not rename a clone that's not in the source hierarchy.
306 		 */
307 		if (!isa_child_of(cn->cn_handle->zfs_name, src))
308 			continue;
309 
310 		/*
311 		 * Destroy the previous mountpoint if needed.
312 		 */
313 		remove_mountpoint(cn->cn_handle);
314 
315 		(void) strlcpy(newname, dst, sizeof (newname));
316 		(void) strcat(newname, cn->cn_handle->zfs_name + strlen(src));
317 
318 		(void) strlcpy(cn->cn_handle->zfs_name, newname,
319 		    sizeof (cn->cn_handle->zfs_name));
320 	}
321 }
322 
323 /*
324  * Given a gathered changelist for the 'sharenfs' or 'sharesmb' property,
325  * unshare all the datasets in the list.
326  */
327 int
changelist_unshare(prop_changelist_t * clp,zfs_share_proto_t * proto)328 changelist_unshare(prop_changelist_t *clp, zfs_share_proto_t *proto)
329 {
330 	prop_changenode_t *cn;
331 	int ret = 0;
332 
333 	if (clp->cl_prop != ZFS_PROP_SHARENFS &&
334 	    clp->cl_prop != ZFS_PROP_SHARESMB)
335 		return (0);
336 
337 	for (cn = uu_list_first(clp->cl_list); cn != NULL;
338 	    cn = uu_list_next(clp->cl_list, cn)) {
339 		if (zfs_unshare_proto(cn->cn_handle, NULL, proto) != 0)
340 			ret = -1;
341 	}
342 
343 	return (ret);
344 }
345 
346 /*
347  * Check if there is any child exported to a local zone in a given changelist.
348  * This information has already been recorded while gathering the changelist
349  * via changelist_gather().
350  */
351 int
changelist_haszonedchild(prop_changelist_t * clp)352 changelist_haszonedchild(prop_changelist_t *clp)
353 {
354 	return (clp->cl_haszonedchild);
355 }
356 
357 /*
358  * Remove a node from a gathered list.
359  */
360 void
changelist_remove(prop_changelist_t * clp,const char * name)361 changelist_remove(prop_changelist_t *clp, const char *name)
362 {
363 	prop_changenode_t *cn;
364 
365 	for (cn = uu_list_first(clp->cl_list); cn != NULL;
366 	    cn = uu_list_next(clp->cl_list, cn)) {
367 
368 		if (strcmp(cn->cn_handle->zfs_name, name) == 0) {
369 			uu_list_remove(clp->cl_list, cn);
370 			zfs_close(cn->cn_handle);
371 			free(cn);
372 			return;
373 		}
374 	}
375 }
376 
377 /*
378  * Release any memory associated with a changelist.
379  */
380 void
changelist_free(prop_changelist_t * clp)381 changelist_free(prop_changelist_t *clp)
382 {
383 	prop_changenode_t *cn;
384 	void *cookie;
385 
386 	if (clp->cl_list) {
387 		cookie = NULL;
388 		while ((cn = uu_list_teardown(clp->cl_list, &cookie)) != NULL) {
389 			zfs_close(cn->cn_handle);
390 			free(cn);
391 		}
392 
393 		uu_list_destroy(clp->cl_list);
394 	}
395 	if (clp->cl_pool)
396 		uu_list_pool_destroy(clp->cl_pool);
397 
398 	free(clp);
399 }
400 
401 static int
change_one(zfs_handle_t * zhp,void * data)402 change_one(zfs_handle_t *zhp, void *data)
403 {
404 	prop_changelist_t *clp = data;
405 	char property[ZFS_MAXPROPLEN];
406 	char where[64];
407 	prop_changenode_t *cn;
408 	zprop_source_t sourcetype;
409 	zprop_source_t share_sourcetype;
410 
411 	/*
412 	 * We only want to unmount/unshare those filesystems that may inherit
413 	 * from the target filesystem.  If we find any filesystem with a
414 	 * locally set mountpoint, we ignore any children since changing the
415 	 * property will not affect them.  If this is a rename, we iterate
416 	 * over all children regardless, since we need them unmounted in
417 	 * order to do the rename.  Also, if this is a volume and we're doing
418 	 * a rename, then always add it to the changelist.
419 	 */
420 
421 	if (!(ZFS_IS_VOLUME(zhp) && clp->cl_realprop == ZFS_PROP_NAME) &&
422 	    zfs_prop_get(zhp, clp->cl_prop, property,
423 	    sizeof (property), &sourcetype, where, sizeof (where),
424 	    B_FALSE) != 0) {
425 		zfs_close(zhp);
426 		return (0);
427 	}
428 
429 	/*
430 	 * If we are "watching" sharenfs or sharesmb
431 	 * then check out the companion property which is tracked
432 	 * in cl_shareprop
433 	 */
434 	if (clp->cl_shareprop != ZPROP_INVAL &&
435 	    zfs_prop_get(zhp, clp->cl_shareprop, property,
436 	    sizeof (property), &share_sourcetype, where, sizeof (where),
437 	    B_FALSE) != 0) {
438 		zfs_close(zhp);
439 		return (0);
440 	}
441 
442 	if (clp->cl_alldependents || clp->cl_allchildren ||
443 	    sourcetype == ZPROP_SRC_DEFAULT ||
444 	    sourcetype == ZPROP_SRC_INHERITED ||
445 	    (clp->cl_shareprop != ZPROP_INVAL &&
446 	    (share_sourcetype == ZPROP_SRC_DEFAULT ||
447 	    share_sourcetype == ZPROP_SRC_INHERITED))) {
448 		if ((cn = zfs_alloc(zfs_get_handle(zhp),
449 		    sizeof (prop_changenode_t))) == NULL) {
450 			zfs_close(zhp);
451 			return (-1);
452 		}
453 
454 		cn->cn_handle = zhp;
455 		cn->cn_mounted = (clp->cl_gflags & CL_GATHER_MOUNT_ALWAYS) ||
456 		    zfs_is_mounted(zhp, NULL);
457 		cn->cn_shared = zfs_is_shared(zhp);
458 		cn->cn_zoned = zfs_prop_get_int(zhp, ZFS_PROP_ZONED);
459 		cn->cn_needpost = B_TRUE;
460 
461 		/* Indicate if any child is exported to a local zone. */
462 		if (getzoneid() == GLOBAL_ZONEID && cn->cn_zoned)
463 			clp->cl_haszonedchild = B_TRUE;
464 
465 		uu_list_node_init(cn, &cn->cn_listnode, clp->cl_pool);
466 
467 		if (clp->cl_sorted) {
468 			uu_list_index_t idx;
469 
470 			(void) uu_list_find(clp->cl_list, cn, NULL,
471 			    &idx);
472 			uu_list_insert(clp->cl_list, cn, idx);
473 		} else {
474 			/*
475 			 * Add this child to beginning of the list. Children
476 			 * below this one in the hierarchy will get added above
477 			 * this one in the list. This produces a list in
478 			 * reverse dataset name order.
479 			 * This is necessary when the original mountpoint
480 			 * is legacy or none.
481 			 */
482 			verify(uu_list_insert_before(clp->cl_list,
483 			    uu_list_first(clp->cl_list), cn) == 0);
484 		}
485 
486 		if (!clp->cl_alldependents)
487 			return (zfs_iter_children(zhp, change_one, data));
488 	} else {
489 		zfs_close(zhp);
490 	}
491 
492 	return (0);
493 }
494 
495 /*ARGSUSED*/
496 static int
compare_mountpoints(const void * a,const void * b,void * unused)497 compare_mountpoints(const void *a, const void *b, void *unused)
498 {
499 	const prop_changenode_t *ca = a;
500 	const prop_changenode_t *cb = b;
501 
502 	char mounta[MAXPATHLEN];
503 	char mountb[MAXPATHLEN];
504 
505 	boolean_t hasmounta, hasmountb;
506 
507 	/*
508 	 * When unsharing or unmounting filesystems, we need to do it in
509 	 * mountpoint order.  This allows the user to have a mountpoint
510 	 * hierarchy that is different from the dataset hierarchy, and still
511 	 * allow it to be changed.  However, if either dataset doesn't have a
512 	 * mountpoint (because it is a volume or a snapshot), we place it at the
513 	 * end of the list, because it doesn't affect our change at all.
514 	 */
515 	hasmounta = (zfs_prop_get(ca->cn_handle, ZFS_PROP_MOUNTPOINT, mounta,
516 	    sizeof (mounta), NULL, NULL, 0, B_FALSE) == 0);
517 	hasmountb = (zfs_prop_get(cb->cn_handle, ZFS_PROP_MOUNTPOINT, mountb,
518 	    sizeof (mountb), NULL, NULL, 0, B_FALSE) == 0);
519 
520 	if (!hasmounta && hasmountb)
521 		return (-1);
522 	else if (hasmounta && !hasmountb)
523 		return (1);
524 	else if (!hasmounta && !hasmountb)
525 		return (0);
526 	else
527 		return (strcmp(mountb, mounta));
528 }
529 
530 /*
531  * Given a ZFS handle and a property, construct a complete list of datasets
532  * that need to be modified as part of this process.  For anything but the
533  * 'mountpoint' and 'sharenfs' properties, this just returns an empty list.
534  * Otherwise, we iterate over all children and look for any datasets that
535  * inherit the property.  For each such dataset, we add it to the list and
536  * mark whether it was shared beforehand.
537  */
538 prop_changelist_t *
changelist_gather(zfs_handle_t * zhp,zfs_prop_t prop,int gather_flags,int mnt_flags)539 changelist_gather(zfs_handle_t *zhp, zfs_prop_t prop, int gather_flags,
540     int mnt_flags)
541 {
542 	prop_changelist_t *clp;
543 	prop_changenode_t *cn;
544 	zfs_handle_t *temp;
545 	char property[ZFS_MAXPROPLEN];
546 	uu_compare_fn_t *compare = NULL;
547 	boolean_t legacy = B_FALSE;
548 
549 	if ((clp = zfs_alloc(zhp->zfs_hdl, sizeof (prop_changelist_t))) == NULL)
550 		return (NULL);
551 
552 	/*
553 	 * For mountpoint-related tasks, we want to sort everything by
554 	 * mountpoint, so that we mount and unmount them in the appropriate
555 	 * order, regardless of their position in the hierarchy.
556 	 */
557 	if (prop == ZFS_PROP_NAME || prop == ZFS_PROP_ZONED ||
558 	    prop == ZFS_PROP_MOUNTPOINT || prop == ZFS_PROP_SHARENFS ||
559 	    prop == ZFS_PROP_SHARESMB) {
560 
561 		if (zfs_prop_get(zhp, ZFS_PROP_MOUNTPOINT,
562 		    property, sizeof (property),
563 		    NULL, NULL, 0, B_FALSE) == 0 &&
564 		    (strcmp(property, "legacy") == 0 ||
565 		    strcmp(property, "none") == 0)) {
566 
567 			legacy = B_TRUE;
568 		}
569 		if (!legacy) {
570 			compare = compare_mountpoints;
571 			clp->cl_sorted = B_TRUE;
572 		}
573 	}
574 
575 	clp->cl_pool = uu_list_pool_create("changelist_pool",
576 	    sizeof (prop_changenode_t),
577 	    offsetof(prop_changenode_t, cn_listnode),
578 	    compare, 0);
579 	if (clp->cl_pool == NULL) {
580 		assert(uu_error() == UU_ERROR_NO_MEMORY);
581 		(void) zfs_error(zhp->zfs_hdl, EZFS_NOMEM, "internal error");
582 		changelist_free(clp);
583 		return (NULL);
584 	}
585 
586 	clp->cl_list = uu_list_create(clp->cl_pool, NULL,
587 	    clp->cl_sorted ? UU_LIST_SORTED : 0);
588 	clp->cl_gflags = gather_flags;
589 	clp->cl_mflags = mnt_flags;
590 
591 	if (clp->cl_list == NULL) {
592 		assert(uu_error() == UU_ERROR_NO_MEMORY);
593 		(void) zfs_error(zhp->zfs_hdl, EZFS_NOMEM, "internal error");
594 		changelist_free(clp);
595 		return (NULL);
596 	}
597 
598 	/*
599 	 * If this is a rename or the 'zoned' property, we pretend we're
600 	 * changing the mountpoint and flag it so we can catch all children in
601 	 * change_one().
602 	 *
603 	 * Flag cl_alldependents to catch all children plus the dependents
604 	 * (clones) that are not in the hierarchy.
605 	 */
606 	if (prop == ZFS_PROP_NAME) {
607 		clp->cl_prop = ZFS_PROP_MOUNTPOINT;
608 		clp->cl_alldependents = B_TRUE;
609 	} else if (prop == ZFS_PROP_ZONED) {
610 		clp->cl_prop = ZFS_PROP_MOUNTPOINT;
611 		clp->cl_allchildren = B_TRUE;
612 	} else if (prop == ZFS_PROP_CANMOUNT) {
613 		clp->cl_prop = ZFS_PROP_MOUNTPOINT;
614 	} else if (prop == ZFS_PROP_VOLSIZE) {
615 		clp->cl_prop = ZFS_PROP_MOUNTPOINT;
616 	} else {
617 		clp->cl_prop = prop;
618 	}
619 	clp->cl_realprop = prop;
620 
621 	if (clp->cl_prop != ZFS_PROP_MOUNTPOINT &&
622 	    clp->cl_prop != ZFS_PROP_SHARENFS &&
623 	    clp->cl_prop != ZFS_PROP_SHARESMB)
624 		return (clp);
625 
626 	/*
627 	 * If watching SHARENFS or SHARESMB then
628 	 * also watch its companion property.
629 	 */
630 	if (clp->cl_prop == ZFS_PROP_SHARENFS)
631 		clp->cl_shareprop = ZFS_PROP_SHARESMB;
632 	else if (clp->cl_prop == ZFS_PROP_SHARESMB)
633 		clp->cl_shareprop = ZFS_PROP_SHARENFS;
634 
635 	if (clp->cl_alldependents) {
636 		if (zfs_iter_dependents(zhp, B_TRUE, change_one, clp) != 0) {
637 			changelist_free(clp);
638 			return (NULL);
639 		}
640 	} else if (zfs_iter_children(zhp, change_one, clp) != 0) {
641 		changelist_free(clp);
642 		return (NULL);
643 	}
644 
645 	/*
646 	 * We have to re-open ourselves because we auto-close all the handles
647 	 * and can't tell the difference.
648 	 */
649 	if ((temp = zfs_open(zhp->zfs_hdl, zfs_get_name(zhp),
650 	    ZFS_TYPE_DATASET)) == NULL) {
651 		changelist_free(clp);
652 		return (NULL);
653 	}
654 
655 	/*
656 	 * Always add ourself to the list.  We add ourselves to the end so that
657 	 * we're the last to be unmounted.
658 	 */
659 	if ((cn = zfs_alloc(zhp->zfs_hdl,
660 	    sizeof (prop_changenode_t))) == NULL) {
661 		zfs_close(temp);
662 		changelist_free(clp);
663 		return (NULL);
664 	}
665 
666 	cn->cn_handle = temp;
667 	cn->cn_mounted = (clp->cl_gflags & CL_GATHER_MOUNT_ALWAYS) ||
668 	    zfs_is_mounted(temp, NULL);
669 	cn->cn_shared = zfs_is_shared(temp);
670 	cn->cn_zoned = zfs_prop_get_int(zhp, ZFS_PROP_ZONED);
671 	cn->cn_needpost = B_TRUE;
672 
673 	uu_list_node_init(cn, &cn->cn_listnode, clp->cl_pool);
674 	if (clp->cl_sorted) {
675 		uu_list_index_t idx;
676 		(void) uu_list_find(clp->cl_list, cn, NULL, &idx);
677 		uu_list_insert(clp->cl_list, cn, idx);
678 	} else {
679 		/*
680 		 * Add the target dataset to the end of the list.
681 		 * The list is not really unsorted. The list will be
682 		 * in reverse dataset name order. This is necessary
683 		 * when the original mountpoint is legacy or none.
684 		 */
685 		verify(uu_list_insert_after(clp->cl_list,
686 		    uu_list_last(clp->cl_list), cn) == 0);
687 	}
688 
689 	/*
690 	 * If the mountpoint property was previously 'legacy', or 'none',
691 	 * record it as the behavior of changelist_postfix() will be different.
692 	 */
693 	if ((clp->cl_prop == ZFS_PROP_MOUNTPOINT) && legacy) {
694 		/*
695 		 * do not automatically mount ex-legacy datasets if
696 		 * we specifically set canmount to noauto
697 		 */
698 		if (zfs_prop_get_int(zhp, ZFS_PROP_CANMOUNT) !=
699 		    ZFS_CANMOUNT_NOAUTO)
700 			clp->cl_waslegacy = B_TRUE;
701 	}
702 
703 	return (clp);
704 }
705