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      1 /*
      2  * CDDL HEADER START
      3  *
      4  * The contents of this file are subject to the terms of the
      5  * Common Development and Distribution License (the "License").
      6  * You may not use this file except in compliance with the License.
      7  *
      8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
      9  * or http://www.opensolaris.org/os/licensing.
     10  * See the License for the specific language governing permissions
     11  * and limitations under the License.
     12  *
     13  * When distributing Covered Code, include this CDDL HEADER in each
     14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
     15  * If applicable, add the following below this CDDL HEADER, with the
     16  * fields enclosed by brackets "[]" replaced with your own identifying
     17  * information: Portions Copyright [yyyy] [name of copyright owner]
     18  *
     19  * CDDL HEADER END
     20  */
     21 
     22 /*
     23  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
     24  * Use is subject to license terms.
     25  *
     26  * Portions Copyright 2007 Ramprakash Jelari
     27  */
     28 
     29 #include <libintl.h>
     30 #include <libuutil.h>
     31 #include <stddef.h>
     32 #include <stdlib.h>
     33 #include <string.h>
     34 #include <unistd.h>
     35 #include <zone.h>
     36 
     37 #include <libzfs.h>
     38 
     39 #include "libzfs_impl.h"
     40 
     41 /*
     42  * Structure to keep track of dataset state.  Before changing the 'sharenfs' or
     43  * 'mountpoint' property, we record whether the filesystem was previously
     44  * mounted/shared.  This prior state dictates whether we remount/reshare the
     45  * dataset after the property has been changed.
     46  *
     47  * The interface consists of the following sequence of functions:
     48  *
     49  * 	changelist_gather()
     50  * 	changelist_prefix()
     51  * 	< change property >
     52  * 	changelist_postfix()
     53  * 	changelist_free()
     54  *
     55  * Other interfaces:
     56  *
     57  * changelist_remove() - remove a node from a gathered list
     58  * changelist_rename() - renames all datasets appropriately when doing a rename
     59  * changelist_unshare() - unshares all the nodes in a given changelist
     60  * changelist_haszonedchild() - check if there is any child exported to
     61  *				a local zone
     62  */
     63 typedef struct prop_changenode {
     64 	zfs_handle_t		*cn_handle;
     65 	int			cn_shared;
     66 	int			cn_mounted;
     67 	int			cn_zoned;
     68 	boolean_t		cn_needpost;	/* is postfix() needed? */
     69 	uu_list_node_t		cn_listnode;
     70 } prop_changenode_t;
     71 
     72 struct prop_changelist {
     73 	zfs_prop_t		cl_prop;
     74 	zfs_prop_t		cl_realprop;
     75 	zfs_prop_t		cl_shareprop;  /* used with sharenfs/sharesmb */
     76 	uu_list_pool_t		*cl_pool;
     77 	uu_list_t		*cl_list;
     78 	boolean_t		cl_waslegacy;
     79 	boolean_t		cl_allchildren;
     80 	boolean_t		cl_alldependents;
     81 	int			cl_mflags;	/* Mount flags */
     82 	int			cl_gflags;	/* Gather request flags */
     83 	boolean_t		cl_haszonedchild;
     84 	boolean_t		cl_sorted;
     85 };
     86 
     87 /*
     88  * If the property is 'mountpoint', go through and unmount filesystems as
     89  * necessary.  We don't do the same for 'sharenfs', because we can just re-share
     90  * with different options without interrupting service. We do handle 'sharesmb'
     91  * since there may be old resource names that need to be removed.
     92  */
     93 int
     94 changelist_prefix(prop_changelist_t *clp)
     95 {
     96 	prop_changenode_t *cn;
     97 	int ret = 0;
     98 
     99 	if (clp->cl_prop != ZFS_PROP_MOUNTPOINT &&
    100 	    clp->cl_prop != ZFS_PROP_SHARESMB)
    101 		return (0);
    102 
    103 	for (cn = uu_list_first(clp->cl_list); cn != NULL;
    104 	    cn = uu_list_next(clp->cl_list, cn)) {
    105 
    106 		/* if a previous loop failed, set the remaining to false */
    107 		if (ret == -1) {
    108 			cn->cn_needpost = B_FALSE;
    109 			continue;
    110 		}
    111 
    112 		/*
    113 		 * If we are in the global zone, but this dataset is exported
    114 		 * to a local zone, do nothing.
    115 		 */
    116 		if (getzoneid() == GLOBAL_ZONEID && cn->cn_zoned)
    117 			continue;
    118 
    119 		if (ZFS_IS_VOLUME(cn->cn_handle)) {
    120 			switch (clp->cl_realprop) {
    121 			case ZFS_PROP_NAME:
    122 				/* If this was a rename, unshare the zvol */
    123 				(void) zfs_unshare_iscsi(cn->cn_handle);
    124 				break;
    125 
    126 			case ZFS_PROP_VOLSIZE:
    127 				/*
    128 				 * If this was a change to the volume size, we
    129 				 * need to unshare and reshare the volume.
    130 				 */
    131 				(void) zfs_unshare_iscsi(cn->cn_handle);
    132 				break;
    133 			}
    134 		} else {
    135 			/*
    136 			 * Do the property specific processing.
    137 			 */
    138 			switch (clp->cl_prop) {
    139 			case ZFS_PROP_MOUNTPOINT:
    140 				if (zfs_unmount(cn->cn_handle, NULL,
    141 				    clp->cl_mflags) != 0) {
    142 					ret = -1;
    143 					cn->cn_needpost = B_FALSE;
    144 				}
    145 				break;
    146 			case ZFS_PROP_SHARESMB:
    147 				(void) zfs_unshare_smb(cn->cn_handle, NULL);
    148 				break;
    149 			}
    150 		}
    151 	}
    152 
    153 	if (ret == -1)
    154 		(void) changelist_postfix(clp);
    155 
    156 	return (ret);
    157 }
    158 
    159 /*
    160  * If the property is 'mountpoint' or 'sharenfs', go through and remount and/or
    161  * reshare the filesystems as necessary.  In changelist_gather() we recorded
    162  * whether the filesystem was previously shared or mounted.  The action we take
    163  * depends on the previous state, and whether the value was previously 'legacy'.
    164  * For non-legacy properties, we only remount/reshare the filesystem if it was
    165  * previously mounted/shared.  Otherwise, we always remount/reshare the
    166  * filesystem.
    167  */
    168 int
    169 changelist_postfix(prop_changelist_t *clp)
    170 {
    171 	prop_changenode_t *cn;
    172 	char shareopts[ZFS_MAXPROPLEN];
    173 	int errors = 0;
    174 	libzfs_handle_t *hdl;
    175 
    176 	/*
    177 	 * If we're changing the mountpoint, attempt to destroy the underlying
    178 	 * mountpoint.  All other datasets will have inherited from this dataset
    179 	 * (in which case their mountpoints exist in the filesystem in the new
    180 	 * location), or have explicit mountpoints set (in which case they won't
    181 	 * be in the changelist).
    182 	 */
    183 	if ((cn = uu_list_last(clp->cl_list)) == NULL)
    184 		return (0);
    185 
    186 	if (clp->cl_prop == ZFS_PROP_MOUNTPOINT)
    187 		remove_mountpoint(cn->cn_handle);
    188 
    189 	/*
    190 	 * It is possible that the changelist_prefix() used libshare
    191 	 * to unshare some entries. Since libshare caches data, an
    192 	 * attempt to reshare during postfix can fail unless libshare
    193 	 * is uninitialized here so that it will reinitialize later.
    194 	 */
    195 	if (cn->cn_handle != NULL) {
    196 		hdl = cn->cn_handle->zfs_hdl;
    197 		assert(hdl != NULL);
    198 		zfs_uninit_libshare(hdl);
    199 	}
    200 
    201 	/*
    202 	 * We walk the datasets in reverse, because we want to mount any parent
    203 	 * datasets before mounting the children.  We walk all datasets even if
    204 	 * there are errors.
    205 	 */
    206 	for (cn = uu_list_last(clp->cl_list); cn != NULL;
    207 	    cn = uu_list_prev(clp->cl_list, cn)) {
    208 
    209 		boolean_t sharenfs;
    210 		boolean_t sharesmb;
    211 		boolean_t mounted;
    212 
    213 		/*
    214 		 * If we are in the global zone, but this dataset is exported
    215 		 * to a local zone, do nothing.
    216 		 */
    217 		if (getzoneid() == GLOBAL_ZONEID && cn->cn_zoned)
    218 			continue;
    219 
    220 		/* Only do post-processing if it's required */
    221 		if (!cn->cn_needpost)
    222 			continue;
    223 		cn->cn_needpost = B_FALSE;
    224 
    225 		zfs_refresh_properties(cn->cn_handle);
    226 
    227 		if (ZFS_IS_VOLUME(cn->cn_handle)) {
    228 			if (cn->cn_shared ||
    229 			    clp->cl_prop == ZFS_PROP_SHAREISCSI) {
    230 				if (zfs_prop_get(cn->cn_handle,
    231 				    ZFS_PROP_SHAREISCSI, shareopts,
    232 				    sizeof (shareopts), NULL, NULL, 0,
    233 				    B_FALSE) == 0 &&
    234 				    strcmp(shareopts, "off") == 0) {
    235 					errors +=
    236 					    zfs_unshare_iscsi(cn->cn_handle);
    237 				} else {
    238 					errors +=
    239 					    zfs_share_iscsi(cn->cn_handle);
    240 				}
    241 			}
    242 
    243 			continue;
    244 		}
    245 
    246 		/*
    247 		 * Remount if previously mounted or mountpoint was legacy,
    248 		 * or sharenfs or sharesmb  property is set.
    249 		 */
    250 		sharenfs = ((zfs_prop_get(cn->cn_handle, ZFS_PROP_SHARENFS,
    251 		    shareopts, sizeof (shareopts), NULL, NULL, 0,
    252 		    B_FALSE) == 0) && (strcmp(shareopts, "off") != 0));
    253 
    254 		sharesmb = ((zfs_prop_get(cn->cn_handle, ZFS_PROP_SHARESMB,
    255 		    shareopts, sizeof (shareopts), NULL, NULL, 0,
    256 		    B_FALSE) == 0) && (strcmp(shareopts, "off") != 0));
    257 
    258 		mounted = zfs_is_mounted(cn->cn_handle, NULL);
    259 
    260 		if (!mounted && (cn->cn_mounted ||
    261 		    ((sharenfs || sharesmb || clp->cl_waslegacy) &&
    262 		    (zfs_prop_get_int(cn->cn_handle,
    263 		    ZFS_PROP_CANMOUNT) == ZFS_CANMOUNT_ON)))) {
    264 
    265 			if (zfs_mount(cn->cn_handle, NULL, 0) != 0)
    266 				errors++;
    267 			else
    268 				mounted = TRUE;
    269 		}
    270 
    271 		/*
    272 		 * If the file system is mounted we always re-share even
    273 		 * if the filesystem is currently shared, so that we can
    274 		 * adopt any new options.
    275 		 */
    276 		if (sharenfs && mounted)
    277 			errors += zfs_share_nfs(cn->cn_handle);
    278 		else if (cn->cn_shared || clp->cl_waslegacy)
    279 			errors += zfs_unshare_nfs(cn->cn_handle, NULL);
    280 		if (sharesmb && mounted)
    281 			errors += zfs_share_smb(cn->cn_handle);
    282 		else if (cn->cn_shared || clp->cl_waslegacy)
    283 			errors += zfs_unshare_smb(cn->cn_handle, NULL);
    284 	}
    285 
    286 	return (errors ? -1 : 0);
    287 }
    288 
    289 /*
    290  * Is this "dataset" a child of "parent"?
    291  */
    292 boolean_t
    293 isa_child_of(const char *dataset, const char *parent)
    294 {
    295 	int len;
    296 
    297 	len = strlen(parent);
    298 
    299 	if (strncmp(dataset, parent, len) == 0 &&
    300 	    (dataset[len] == '@' || dataset[len] == '/' ||
    301 	    dataset[len] == '\0'))
    302 		return (B_TRUE);
    303 	else
    304 		return (B_FALSE);
    305 
    306 }
    307 
    308 /*
    309  * If we rename a filesystem, child filesystem handles are no longer valid
    310  * since we identify each dataset by its name in the ZFS namespace.  As a
    311  * result, we have to go through and fix up all the names appropriately.  We
    312  * could do this automatically if libzfs kept track of all open handles, but
    313  * this is a lot less work.
    314  */
    315 void
    316 changelist_rename(prop_changelist_t *clp, const char *src, const char *dst)
    317 {
    318 	prop_changenode_t *cn;
    319 	char newname[ZFS_MAXNAMELEN];
    320 
    321 	for (cn = uu_list_first(clp->cl_list); cn != NULL;
    322 	    cn = uu_list_next(clp->cl_list, cn)) {
    323 		/*
    324 		 * Do not rename a clone that's not in the source hierarchy.
    325 		 */
    326 		if (!isa_child_of(cn->cn_handle->zfs_name, src))
    327 			continue;
    328 
    329 		/*
    330 		 * Destroy the previous mountpoint if needed.
    331 		 */
    332 		remove_mountpoint(cn->cn_handle);
    333 
    334 		(void) strlcpy(newname, dst, sizeof (newname));
    335 		(void) strcat(newname, cn->cn_handle->zfs_name + strlen(src));
    336 
    337 		(void) strlcpy(cn->cn_handle->zfs_name, newname,
    338 		    sizeof (cn->cn_handle->zfs_name));
    339 	}
    340 }
    341 
    342 /*
    343  * Given a gathered changelist for the 'sharenfs' or 'sharesmb' property,
    344  * unshare all the datasets in the list.
    345  */
    346 int
    347 changelist_unshare(prop_changelist_t *clp, zfs_share_proto_t *proto)
    348 {
    349 	prop_changenode_t *cn;
    350 	int ret = 0;
    351 
    352 	if (clp->cl_prop != ZFS_PROP_SHARENFS &&
    353 	    clp->cl_prop != ZFS_PROP_SHARESMB)
    354 		return (0);
    355 
    356 	for (cn = uu_list_first(clp->cl_list); cn != NULL;
    357 	    cn = uu_list_next(clp->cl_list, cn)) {
    358 		if (zfs_unshare_proto(cn->cn_handle, NULL, proto) != 0)
    359 			ret = -1;
    360 	}
    361 
    362 	return (ret);
    363 }
    364 
    365 /*
    366  * Check if there is any child exported to a local zone in a given changelist.
    367  * This information has already been recorded while gathering the changelist
    368  * via changelist_gather().
    369  */
    370 int
    371 changelist_haszonedchild(prop_changelist_t *clp)
    372 {
    373 	return (clp->cl_haszonedchild);
    374 }
    375 
    376 /*
    377  * Remove a node from a gathered list.
    378  */
    379 void
    380 changelist_remove(prop_changelist_t *clp, const char *name)
    381 {
    382 	prop_changenode_t *cn;
    383 
    384 	for (cn = uu_list_first(clp->cl_list); cn != NULL;
    385 	    cn = uu_list_next(clp->cl_list, cn)) {
    386 
    387 		if (strcmp(cn->cn_handle->zfs_name, name) == 0) {
    388 			uu_list_remove(clp->cl_list, cn);
    389 			zfs_close(cn->cn_handle);
    390 			free(cn);
    391 			return;
    392 		}
    393 	}
    394 }
    395 
    396 /*
    397  * Release any memory associated with a changelist.
    398  */
    399 void
    400 changelist_free(prop_changelist_t *clp)
    401 {
    402 	prop_changenode_t *cn;
    403 	void *cookie;
    404 
    405 	if (clp->cl_list) {
    406 		cookie = NULL;
    407 		while ((cn = uu_list_teardown(clp->cl_list, &cookie)) != NULL) {
    408 			zfs_close(cn->cn_handle);
    409 			free(cn);
    410 		}
    411 
    412 		uu_list_destroy(clp->cl_list);
    413 	}
    414 	if (clp->cl_pool)
    415 		uu_list_pool_destroy(clp->cl_pool);
    416 
    417 	free(clp);
    418 }
    419 
    420 static int
    421 change_one(zfs_handle_t *zhp, void *data)
    422 {
    423 	prop_changelist_t *clp = data;
    424 	char property[ZFS_MAXPROPLEN];
    425 	char where[64];
    426 	prop_changenode_t *cn;
    427 	zprop_source_t sourcetype;
    428 	zprop_source_t share_sourcetype;
    429 
    430 	/*
    431 	 * We only want to unmount/unshare those filesystems that may inherit
    432 	 * from the target filesystem.  If we find any filesystem with a
    433 	 * locally set mountpoint, we ignore any children since changing the
    434 	 * property will not affect them.  If this is a rename, we iterate
    435 	 * over all children regardless, since we need them unmounted in
    436 	 * order to do the rename.  Also, if this is a volume and we're doing
    437 	 * a rename, then always add it to the changelist.
    438 	 */
    439 
    440 	if (!(ZFS_IS_VOLUME(zhp) && clp->cl_realprop == ZFS_PROP_NAME) &&
    441 	    zfs_prop_get(zhp, clp->cl_prop, property,
    442 	    sizeof (property), &sourcetype, where, sizeof (where),
    443 	    B_FALSE) != 0) {
    444 		zfs_close(zhp);
    445 		return (0);
    446 	}
    447 
    448 	/*
    449 	 * If we are "watching" sharenfs or sharesmb
    450 	 * then check out the companion property which is tracked
    451 	 * in cl_shareprop
    452 	 */
    453 	if (clp->cl_shareprop != ZPROP_INVAL &&
    454 	    zfs_prop_get(zhp, clp->cl_shareprop, property,
    455 	    sizeof (property), &share_sourcetype, where, sizeof (where),
    456 	    B_FALSE) != 0) {
    457 		zfs_close(zhp);
    458 		return (0);
    459 	}
    460 
    461 	if (clp->cl_alldependents || clp->cl_allchildren ||
    462 	    sourcetype == ZPROP_SRC_DEFAULT ||
    463 	    sourcetype == ZPROP_SRC_INHERITED ||
    464 	    (clp->cl_shareprop != ZPROP_INVAL &&
    465 	    (share_sourcetype == ZPROP_SRC_DEFAULT ||
    466 	    share_sourcetype == ZPROP_SRC_INHERITED))) {
    467 		if ((cn = zfs_alloc(zfs_get_handle(zhp),
    468 		    sizeof (prop_changenode_t))) == NULL) {
    469 			zfs_close(zhp);
    470 			return (-1);
    471 		}
    472 
    473 		cn->cn_handle = zhp;
    474 		cn->cn_mounted = (clp->cl_gflags & CL_GATHER_MOUNT_ALWAYS) ||
    475 		    zfs_is_mounted(zhp, NULL);
    476 		cn->cn_shared = zfs_is_shared(zhp);
    477 		cn->cn_zoned = zfs_prop_get_int(zhp, ZFS_PROP_ZONED);
    478 		cn->cn_needpost = B_TRUE;
    479 
    480 		/* Indicate if any child is exported to a local zone. */
    481 		if (getzoneid() == GLOBAL_ZONEID && cn->cn_zoned)
    482 			clp->cl_haszonedchild = B_TRUE;
    483 
    484 		uu_list_node_init(cn, &cn->cn_listnode, clp->cl_pool);
    485 
    486 		if (clp->cl_sorted) {
    487 			uu_list_index_t idx;
    488 
    489 			(void) uu_list_find(clp->cl_list, cn, NULL,
    490 			    &idx);
    491 			uu_list_insert(clp->cl_list, cn, idx);
    492 		} else {
    493 			/*
    494 			 * Add this child to beginning of the list. Children
    495 			 * below this one in the hierarchy will get added above
    496 			 * this one in the list. This produces a list in
    497 			 * reverse dataset name order.
    498 			 * This is necessary when the original mountpoint
    499 			 * is legacy or none.
    500 			 */
    501 			ASSERT(!clp->cl_alldependents);
    502 			verify(uu_list_insert_before(clp->cl_list,
    503 			    uu_list_first(clp->cl_list), cn) == 0);
    504 		}
    505 
    506 		if (!clp->cl_alldependents)
    507 			return (zfs_iter_children(zhp, change_one, data));
    508 	} else {
    509 		zfs_close(zhp);
    510 	}
    511 
    512 	return (0);
    513 }
    514 
    515 /*ARGSUSED*/
    516 static int
    517 compare_mountpoints(const void *a, const void *b, void *unused)
    518 {
    519 	const prop_changenode_t *ca = a;
    520 	const prop_changenode_t *cb = b;
    521 
    522 	char mounta[MAXPATHLEN];
    523 	char mountb[MAXPATHLEN];
    524 
    525 	boolean_t hasmounta, hasmountb;
    526 
    527 	/*
    528 	 * When unsharing or unmounting filesystems, we need to do it in
    529 	 * mountpoint order.  This allows the user to have a mountpoint
    530 	 * hierarchy that is different from the dataset hierarchy, and still
    531 	 * allow it to be changed.  However, if either dataset doesn't have a
    532 	 * mountpoint (because it is a volume or a snapshot), we place it at the
    533 	 * end of the list, because it doesn't affect our change at all.
    534 	 */
    535 	hasmounta = (zfs_prop_get(ca->cn_handle, ZFS_PROP_MOUNTPOINT, mounta,
    536 	    sizeof (mounta), NULL, NULL, 0, B_FALSE) == 0);
    537 	hasmountb = (zfs_prop_get(cb->cn_handle, ZFS_PROP_MOUNTPOINT, mountb,
    538 	    sizeof (mountb), NULL, NULL, 0, B_FALSE) == 0);
    539 
    540 	if (!hasmounta && hasmountb)
    541 		return (-1);
    542 	else if (hasmounta && !hasmountb)
    543 		return (1);
    544 	else if (!hasmounta && !hasmountb)
    545 		return (0);
    546 	else
    547 		return (strcmp(mountb, mounta));
    548 }
    549 
    550 /*
    551  * Given a ZFS handle and a property, construct a complete list of datasets
    552  * that need to be modified as part of this process.  For anything but the
    553  * 'mountpoint' and 'sharenfs' properties, this just returns an empty list.
    554  * Otherwise, we iterate over all children and look for any datasets that
    555  * inherit the property.  For each such dataset, we add it to the list and
    556  * mark whether it was shared beforehand.
    557  */
    558 prop_changelist_t *
    559 changelist_gather(zfs_handle_t *zhp, zfs_prop_t prop, int gather_flags,
    560     int mnt_flags)
    561 {
    562 	prop_changelist_t *clp;
    563 	prop_changenode_t *cn;
    564 	zfs_handle_t *temp;
    565 	char property[ZFS_MAXPROPLEN];
    566 	uu_compare_fn_t *compare = NULL;
    567 	boolean_t legacy = B_FALSE;
    568 
    569 	if ((clp = zfs_alloc(zhp->zfs_hdl, sizeof (prop_changelist_t))) == NULL)
    570 		return (NULL);
    571 
    572 	/*
    573 	 * For mountpoint-related tasks, we want to sort everything by
    574 	 * mountpoint, so that we mount and unmount them in the appropriate
    575 	 * order, regardless of their position in the hierarchy.
    576 	 */
    577 	if (prop == ZFS_PROP_NAME || prop == ZFS_PROP_ZONED ||
    578 	    prop == ZFS_PROP_MOUNTPOINT || prop == ZFS_PROP_SHARENFS ||
    579 	    prop == ZFS_PROP_SHARESMB) {
    580 
    581 		if (zfs_prop_get(zhp, ZFS_PROP_MOUNTPOINT,
    582 		    property, sizeof (property),
    583 		    NULL, NULL, 0, B_FALSE) == 0 &&
    584 		    (strcmp(property, "legacy") == 0 ||
    585 		    strcmp(property, "none") == 0)) {
    586 
    587 			legacy = B_TRUE;
    588 		}
    589 		if (!legacy) {
    590 			compare = compare_mountpoints;
    591 			clp->cl_sorted = B_TRUE;
    592 		}
    593 	}
    594 
    595 	clp->cl_pool = uu_list_pool_create("changelist_pool",
    596 	    sizeof (prop_changenode_t),
    597 	    offsetof(prop_changenode_t, cn_listnode),
    598 	    compare, 0);
    599 	if (clp->cl_pool == NULL) {
    600 		assert(uu_error() == UU_ERROR_NO_MEMORY);
    601 		(void) zfs_error(zhp->zfs_hdl, EZFS_NOMEM, "internal error");
    602 		changelist_free(clp);
    603 		return (NULL);
    604 	}
    605 
    606 	clp->cl_list = uu_list_create(clp->cl_pool, NULL,
    607 	    clp->cl_sorted ? UU_LIST_SORTED : 0);
    608 	clp->cl_gflags = gather_flags;
    609 	clp->cl_mflags = mnt_flags;
    610 
    611 	if (clp->cl_list == NULL) {
    612 		assert(uu_error() == UU_ERROR_NO_MEMORY);
    613 		(void) zfs_error(zhp->zfs_hdl, EZFS_NOMEM, "internal error");
    614 		changelist_free(clp);
    615 		return (NULL);
    616 	}
    617 
    618 	/*
    619 	 * If this is a rename or the 'zoned' property, we pretend we're
    620 	 * changing the mountpoint and flag it so we can catch all children in
    621 	 * change_one().
    622 	 *
    623 	 * Flag cl_alldependents to catch all children plus the dependents
    624 	 * (clones) that are not in the hierarchy.
    625 	 */
    626 	if (prop == ZFS_PROP_NAME) {
    627 		clp->cl_prop = ZFS_PROP_MOUNTPOINT;
    628 		clp->cl_alldependents = B_TRUE;
    629 	} else if (prop == ZFS_PROP_ZONED) {
    630 		clp->cl_prop = ZFS_PROP_MOUNTPOINT;
    631 		clp->cl_allchildren = B_TRUE;
    632 	} else if (prop == ZFS_PROP_CANMOUNT) {
    633 		clp->cl_prop = ZFS_PROP_MOUNTPOINT;
    634 	} else if (prop == ZFS_PROP_VOLSIZE) {
    635 		clp->cl_prop = ZFS_PROP_MOUNTPOINT;
    636 	} else {
    637 		clp->cl_prop = prop;
    638 	}
    639 	clp->cl_realprop = prop;
    640 
    641 	if (clp->cl_prop != ZFS_PROP_MOUNTPOINT &&
    642 	    clp->cl_prop != ZFS_PROP_SHARENFS &&
    643 	    clp->cl_prop != ZFS_PROP_SHARESMB &&
    644 	    clp->cl_prop != ZFS_PROP_SHAREISCSI)
    645 		return (clp);
    646 
    647 	/*
    648 	 * If watching SHARENFS or SHARESMB then
    649 	 * also watch its companion property.
    650 	 */
    651 	if (clp->cl_prop == ZFS_PROP_SHARENFS)
    652 		clp->cl_shareprop = ZFS_PROP_SHARESMB;
    653 	else if (clp->cl_prop == ZFS_PROP_SHARESMB)
    654 		clp->cl_shareprop = ZFS_PROP_SHARENFS;
    655 
    656 	if (clp->cl_alldependents) {
    657 		if (zfs_iter_dependents(zhp, B_TRUE, change_one, clp) != 0) {
    658 			changelist_free(clp);
    659 			return (NULL);
    660 		}
    661 	} else if (zfs_iter_children(zhp, change_one, clp) != 0) {
    662 		changelist_free(clp);
    663 		return (NULL);
    664 	}
    665 
    666 	/*
    667 	 * We have to re-open ourselves because we auto-close all the handles
    668 	 * and can't tell the difference.
    669 	 */
    670 	if ((temp = zfs_open(zhp->zfs_hdl, zfs_get_name(zhp),
    671 	    ZFS_TYPE_DATASET)) == NULL) {
    672 		changelist_free(clp);
    673 		return (NULL);
    674 	}
    675 
    676 	/*
    677 	 * Always add ourself to the list.  We add ourselves to the end so that
    678 	 * we're the last to be unmounted.
    679 	 */
    680 	if ((cn = zfs_alloc(zhp->zfs_hdl,
    681 	    sizeof (prop_changenode_t))) == NULL) {
    682 		zfs_close(temp);
    683 		changelist_free(clp);
    684 		return (NULL);
    685 	}
    686 
    687 	cn->cn_handle = temp;
    688 	cn->cn_mounted = (clp->cl_gflags & CL_GATHER_MOUNT_ALWAYS) ||
    689 	    zfs_is_mounted(temp, NULL);
    690 	cn->cn_shared = zfs_is_shared(temp);
    691 	cn->cn_zoned = zfs_prop_get_int(zhp, ZFS_PROP_ZONED);
    692 	cn->cn_needpost = B_TRUE;
    693 
    694 	uu_list_node_init(cn, &cn->cn_listnode, clp->cl_pool);
    695 	if (clp->cl_sorted) {
    696 		uu_list_index_t idx;
    697 		(void) uu_list_find(clp->cl_list, cn, NULL, &idx);
    698 		uu_list_insert(clp->cl_list, cn, idx);
    699 	} else {
    700 		/*
    701 		 * Add the target dataset to the end of the list.
    702 		 * The list is not really unsorted. The list will be
    703 		 * in reverse dataset name order. This is necessary
    704 		 * when the original mountpoint is legacy or none.
    705 		 */
    706 		verify(uu_list_insert_after(clp->cl_list,
    707 		    uu_list_last(clp->cl_list), cn) == 0);
    708 	}
    709 
    710 	/*
    711 	 * If the mountpoint property was previously 'legacy', or 'none',
    712 	 * record it as the behavior of changelist_postfix() will be different.
    713 	 */
    714 	if ((clp->cl_prop == ZFS_PROP_MOUNTPOINT) && legacy) {
    715 		/*
    716 		 * do not automatically mount ex-legacy datasets if
    717 		 * we specifically set canmount to noauto
    718 		 */
    719 		if (zfs_prop_get_int(zhp, ZFS_PROP_CANMOUNT) !=
    720 		    ZFS_CANMOUNT_NOAUTO)
    721 			clp->cl_waslegacy = B_TRUE;
    722 	}
    723 
    724 	return (clp);
    725 }
    726