xref: /freebsd/sys/contrib/openzfs/lib/libzfs/libzfs_changelist.c (revision 61145dc2b94f12f6a47344fb9aac702321880e43)
1 // SPDX-License-Identifier: CDDL-1.0
2 /*
3  * CDDL HEADER START
4  *
5  * The contents of this file are subject to the terms of the
6  * Common Development and Distribution License (the "License").
7  * You may not use this file except in compliance with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or https://opensource.org/licenses/CDDL-1.0.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 
23 /*
24  * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
25  * Use is subject to license terms.
26  *
27  * Portions Copyright 2007 Ramprakash Jelari
28  * Copyright (c) 2014, 2020 by Delphix. All rights reserved.
29  * Copyright 2016 Igor Kozhukhov <ikozhukhov@gmail.com>
30  * Copyright (c) 2018 Datto Inc.
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_avl_node_t		cn_treenode;
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_avl_pool_t		*cl_pool;
81 	uu_avl_t		*cl_tree;
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 };
89 
90 /*
91  * If the property is 'mountpoint', go through and unmount filesystems as
92  * necessary.  We don't do the same for 'sharenfs', because we can just re-share
93  * with different options without interrupting service. We do handle 'sharesmb'
94  * since there may be old resource names that need to be removed.
95  */
96 int
changelist_prefix(prop_changelist_t * clp)97 changelist_prefix(prop_changelist_t *clp)
98 {
99 	prop_changenode_t *cn;
100 	uu_avl_walk_t *walk;
101 	int ret = 0;
102 	const enum sa_protocol smb[] = {SA_PROTOCOL_SMB, SA_NO_PROTOCOL};
103 	boolean_t commit_smb_shares = B_FALSE;
104 
105 	if (clp->cl_prop != ZFS_PROP_MOUNTPOINT &&
106 	    clp->cl_prop != ZFS_PROP_SHARESMB)
107 		return (0);
108 
109 	/*
110 	 * If CL_GATHER_DONT_UNMOUNT is set, don't want to unmount/unshare and
111 	 * later (re)mount/(re)share the filesystem in postfix phase, so we
112 	 * return from here. If filesystem is mounted or unmounted, leave it
113 	 * as it is.
114 	 */
115 	if (clp->cl_gflags & CL_GATHER_DONT_UNMOUNT)
116 		return (0);
117 
118 	if ((walk = uu_avl_walk_start(clp->cl_tree, UU_WALK_ROBUST)) == NULL)
119 		return (-1);
120 
121 	while ((cn = uu_avl_walk_next(walk)) != NULL) {
122 
123 		/* if a previous loop failed, set the remaining to false */
124 		if (ret == -1) {
125 			cn->cn_needpost = B_FALSE;
126 			continue;
127 		}
128 
129 		/*
130 		 * If we are in the global zone, but this dataset is exported
131 		 * to a local zone, do nothing.
132 		 */
133 		if (getzoneid() == GLOBAL_ZONEID && cn->cn_zoned)
134 			continue;
135 
136 		if (!ZFS_IS_VOLUME(cn->cn_handle)) {
137 			/*
138 			 * Do the property specific processing.
139 			 */
140 			switch (clp->cl_prop) {
141 			case ZFS_PROP_MOUNTPOINT:
142 				if (zfs_unmount(cn->cn_handle, NULL,
143 				    clp->cl_mflags) != 0) {
144 					ret = -1;
145 					cn->cn_needpost = B_FALSE;
146 				}
147 				break;
148 			case ZFS_PROP_SHARESMB:
149 				(void) zfs_unshare(cn->cn_handle, NULL,
150 				    smb);
151 				commit_smb_shares = B_TRUE;
152 				break;
153 
154 			default:
155 				break;
156 			}
157 		}
158 	}
159 
160 	if (commit_smb_shares)
161 		zfs_commit_shares(smb);
162 	uu_avl_walk_end(walk);
163 
164 	if (ret == -1)
165 		(void) changelist_postfix(clp);
166 
167 	return (ret);
168 }
169 
170 /*
171  * If the property is 'mountpoint' or 'sharenfs', go through and remount and/or
172  * reshare the filesystems as necessary.  In changelist_gather() we recorded
173  * whether the filesystem was previously shared or mounted.  The action we take
174  * depends on the previous state, and whether the value was previously 'legacy'.
175  * For non-legacy properties, we always remount/reshare the filesystem,
176  * if CL_GATHER_DONT_UNMOUNT is not set.
177  */
178 int
changelist_postfix(prop_changelist_t * clp)179 changelist_postfix(prop_changelist_t *clp)
180 {
181 	prop_changenode_t *cn;
182 	uu_avl_walk_t *walk;
183 	char shareopts[ZFS_MAXPROPLEN];
184 	boolean_t commit_smb_shares = B_FALSE;
185 	boolean_t commit_nfs_shares = B_FALSE;
186 
187 	/*
188 	 * If CL_GATHER_DONT_UNMOUNT is set, it means we don't want to (un)mount
189 	 * or (re/un)share the filesystem, so we return from here. If filesystem
190 	 * is mounted or unmounted, leave it as it is.
191 	 */
192 	if (clp->cl_gflags & CL_GATHER_DONT_UNMOUNT)
193 		return (0);
194 
195 	/*
196 	 * If we're changing the mountpoint, attempt to destroy the underlying
197 	 * mountpoint.  All other datasets will have inherited from this dataset
198 	 * (in which case their mountpoints exist in the filesystem in the new
199 	 * location), or have explicit mountpoints set (in which case they won't
200 	 * be in the changelist).
201 	 */
202 	if ((cn = uu_avl_last(clp->cl_tree)) == NULL)
203 		return (0);
204 
205 	if (clp->cl_prop == ZFS_PROP_MOUNTPOINT &&
206 	    !(clp->cl_gflags & CL_GATHER_DONT_UNMOUNT))
207 		remove_mountpoint(cn->cn_handle);
208 
209 	/*
210 	 * We walk the datasets in reverse, because we want to mount any parent
211 	 * datasets before mounting the children.  We walk all datasets even if
212 	 * there are errors.
213 	 */
214 	if ((walk = uu_avl_walk_start(clp->cl_tree,
215 	    UU_WALK_REVERSE | UU_WALK_ROBUST)) == NULL)
216 		return (-1);
217 
218 	while ((cn = uu_avl_walk_next(walk)) != NULL) {
219 
220 		boolean_t sharenfs;
221 		boolean_t sharesmb;
222 		boolean_t mounted;
223 		boolean_t needs_key;
224 
225 		/*
226 		 * If we are in the global zone, but this dataset is exported
227 		 * to a local zone, do nothing.
228 		 */
229 		if (getzoneid() == GLOBAL_ZONEID && cn->cn_zoned)
230 			continue;
231 
232 		/* Only do post-processing if it's required */
233 		if (!cn->cn_needpost)
234 			continue;
235 		cn->cn_needpost = B_FALSE;
236 
237 		zfs_refresh_properties(cn->cn_handle);
238 
239 		if (ZFS_IS_VOLUME(cn->cn_handle))
240 			continue;
241 
242 		/*
243 		 * Remount if previously mounted or mountpoint was legacy,
244 		 * or sharenfs or sharesmb  property is set.
245 		 */
246 		sharenfs = ((zfs_prop_get(cn->cn_handle, ZFS_PROP_SHARENFS,
247 		    shareopts, sizeof (shareopts), NULL, NULL, 0,
248 		    B_FALSE) == 0) && (strcmp(shareopts, "off") != 0));
249 
250 		sharesmb = ((zfs_prop_get(cn->cn_handle, ZFS_PROP_SHARESMB,
251 		    shareopts, sizeof (shareopts), NULL, NULL, 0,
252 		    B_FALSE) == 0) && (strcmp(shareopts, "off") != 0));
253 
254 		needs_key = (zfs_prop_get_int(cn->cn_handle,
255 		    ZFS_PROP_KEYSTATUS) == ZFS_KEYSTATUS_UNAVAILABLE);
256 
257 		mounted = zfs_is_mounted(cn->cn_handle, NULL);
258 
259 		if (!mounted && !needs_key && (cn->cn_mounted ||
260 		    (((clp->cl_prop == ZFS_PROP_MOUNTPOINT &&
261 		    clp->cl_prop == clp->cl_realprop) ||
262 		    sharenfs || sharesmb || clp->cl_waslegacy) &&
263 		    (zfs_prop_get_int(cn->cn_handle,
264 		    ZFS_PROP_CANMOUNT) == ZFS_CANMOUNT_ON)))) {
265 
266 			if (zfs_mount(cn->cn_handle, NULL, 0) == 0)
267 				mounted = TRUE;
268 		}
269 
270 		/*
271 		 * If the file system is mounted we always re-share even
272 		 * if the filesystem is currently shared, so that we can
273 		 * adopt any new options.
274 		 */
275 		const enum sa_protocol nfs[] =
276 		    {SA_PROTOCOL_NFS, SA_NO_PROTOCOL};
277 		if (sharenfs && mounted) {
278 			zfs_share(cn->cn_handle, nfs);
279 			commit_nfs_shares = B_TRUE;
280 		} else if (cn->cn_shared || clp->cl_waslegacy) {
281 			zfs_unshare(cn->cn_handle, NULL, nfs);
282 			commit_nfs_shares = B_TRUE;
283 		}
284 		const enum sa_protocol smb[] =
285 		    {SA_PROTOCOL_SMB, SA_NO_PROTOCOL};
286 		if (sharesmb && mounted) {
287 			zfs_share(cn->cn_handle, smb);
288 			commit_smb_shares = B_TRUE;
289 		} else if (cn->cn_shared || clp->cl_waslegacy) {
290 			zfs_unshare(cn->cn_handle, NULL, smb);
291 			commit_smb_shares = B_TRUE;
292 		}
293 	}
294 
295 	enum sa_protocol proto[SA_PROTOCOL_COUNT + 1], *p = proto;
296 	if (commit_nfs_shares)
297 		*p++ = SA_PROTOCOL_NFS;
298 	if (commit_smb_shares)
299 		*p++ = SA_PROTOCOL_SMB;
300 	*p++ = SA_NO_PROTOCOL;
301 	zfs_commit_shares(proto);
302 	uu_avl_walk_end(walk);
303 
304 	return (0);
305 }
306 
307 /*
308  * Is this "dataset" a child of "parent"?
309  */
310 static boolean_t
isa_child_of(const char * dataset,const char * parent)311 isa_child_of(const char *dataset, const char *parent)
312 {
313 	int len;
314 
315 	len = strlen(parent);
316 
317 	if (strncmp(dataset, parent, len) == 0 &&
318 	    (dataset[len] == '@' || dataset[len] == '/' ||
319 	    dataset[len] == '\0'))
320 		return (B_TRUE);
321 	else
322 		return (B_FALSE);
323 
324 }
325 
326 /*
327  * If we rename a filesystem, child filesystem handles are no longer valid
328  * since we identify each dataset by its name in the ZFS namespace.  As a
329  * result, we have to go through and fix up all the names appropriately.  We
330  * could do this automatically if libzfs kept track of all open handles, but
331  * this is a lot less work.
332  */
333 void
changelist_rename(prop_changelist_t * clp,const char * src,const char * dst)334 changelist_rename(prop_changelist_t *clp, const char *src, const char *dst)
335 {
336 	prop_changenode_t *cn;
337 	uu_avl_walk_t *walk;
338 	char newname[ZFS_MAX_DATASET_NAME_LEN];
339 
340 	if ((walk = uu_avl_walk_start(clp->cl_tree, UU_WALK_ROBUST)) == NULL)
341 		return;
342 
343 	while ((cn = uu_avl_walk_next(walk)) != NULL) {
344 		/*
345 		 * Do not rename a clone that's not in the source hierarchy.
346 		 */
347 		if (!isa_child_of(cn->cn_handle->zfs_name, src))
348 			continue;
349 
350 		/*
351 		 * Destroy the previous mountpoint if needed.
352 		 */
353 		remove_mountpoint(cn->cn_handle);
354 
355 		(void) strlcpy(newname, dst, sizeof (newname));
356 		(void) strlcat(newname, cn->cn_handle->zfs_name + strlen(src),
357 		    sizeof (newname));
358 
359 		(void) strlcpy(cn->cn_handle->zfs_name, newname,
360 		    sizeof (cn->cn_handle->zfs_name));
361 	}
362 
363 	uu_avl_walk_end(walk);
364 }
365 
366 /*
367  * Given a gathered changelist for the 'sharenfs' or 'sharesmb' property,
368  * unshare all the datasets in the list.
369  */
370 int
changelist_unshare(prop_changelist_t * clp,const enum sa_protocol * proto)371 changelist_unshare(prop_changelist_t *clp, const enum sa_protocol *proto)
372 {
373 	prop_changenode_t *cn;
374 	uu_avl_walk_t *walk;
375 	int ret = 0;
376 
377 	if (clp->cl_prop != ZFS_PROP_SHARENFS &&
378 	    clp->cl_prop != ZFS_PROP_SHARESMB)
379 		return (0);
380 
381 	if ((walk = uu_avl_walk_start(clp->cl_tree, UU_WALK_ROBUST)) == NULL)
382 		return (-1);
383 
384 	while ((cn = uu_avl_walk_next(walk)) != NULL) {
385 		if (zfs_unshare(cn->cn_handle, NULL, proto) != 0)
386 			ret = -1;
387 	}
388 
389 	for (const enum sa_protocol *p = proto; *p != SA_NO_PROTOCOL; ++p)
390 		sa_commit_shares(*p);
391 	uu_avl_walk_end(walk);
392 
393 	return (ret);
394 }
395 
396 /*
397  * Check if there is any child exported to a local zone in a given changelist.
398  * This information has already been recorded while gathering the changelist
399  * via changelist_gather().
400  */
401 int
changelist_haszonedchild(prop_changelist_t * clp)402 changelist_haszonedchild(prop_changelist_t *clp)
403 {
404 	return (clp->cl_haszonedchild);
405 }
406 
407 /*
408  * Remove a node from a gathered list.
409  */
410 void
changelist_remove(prop_changelist_t * clp,const char * name)411 changelist_remove(prop_changelist_t *clp, const char *name)
412 {
413 	prop_changenode_t *cn;
414 	uu_avl_walk_t *walk;
415 
416 	if ((walk = uu_avl_walk_start(clp->cl_tree, UU_WALK_ROBUST)) == NULL)
417 		return;
418 
419 	while ((cn = uu_avl_walk_next(walk)) != NULL) {
420 		if (strcmp(cn->cn_handle->zfs_name, name) == 0) {
421 			uu_avl_remove(clp->cl_tree, cn);
422 			zfs_close(cn->cn_handle);
423 			free(cn);
424 			uu_avl_walk_end(walk);
425 			return;
426 		}
427 	}
428 
429 	uu_avl_walk_end(walk);
430 }
431 
432 /*
433  * Release any memory associated with a changelist.
434  */
435 void
changelist_free(prop_changelist_t * clp)436 changelist_free(prop_changelist_t *clp)
437 {
438 	prop_changenode_t *cn;
439 
440 	if (clp->cl_tree) {
441 		uu_avl_walk_t *walk;
442 
443 		if ((walk = uu_avl_walk_start(clp->cl_tree,
444 		    UU_WALK_ROBUST)) == NULL)
445 			return;
446 
447 		while ((cn = uu_avl_walk_next(walk)) != NULL) {
448 			uu_avl_remove(clp->cl_tree, cn);
449 			zfs_close(cn->cn_handle);
450 			free(cn);
451 		}
452 
453 		uu_avl_walk_end(walk);
454 		uu_avl_destroy(clp->cl_tree);
455 	}
456 	if (clp->cl_pool)
457 		uu_avl_pool_destroy(clp->cl_pool);
458 
459 	free(clp);
460 }
461 
462 /*
463  * Add one dataset to changelist
464  */
465 static int
changelist_add_mounted(zfs_handle_t * zhp,void * data)466 changelist_add_mounted(zfs_handle_t *zhp, void *data)
467 {
468 	prop_changelist_t *clp = data;
469 	prop_changenode_t *cn;
470 	uu_avl_index_t idx;
471 
472 	ASSERT3U(clp->cl_prop, ==, ZFS_PROP_MOUNTPOINT);
473 
474 	cn = zfs_alloc(zfs_get_handle(zhp), sizeof (prop_changenode_t));
475 	cn->cn_handle = zhp;
476 	cn->cn_mounted = zfs_is_mounted(zhp, NULL);
477 	ASSERT3U(cn->cn_mounted, ==, B_TRUE);
478 	cn->cn_shared = zfs_is_shared(zhp, NULL, NULL);
479 	cn->cn_zoned = zfs_prop_get_int(zhp, ZFS_PROP_ZONED);
480 	cn->cn_needpost = B_TRUE;
481 
482 	/* Indicate if any child is exported to a local zone. */
483 	if (getzoneid() == GLOBAL_ZONEID && cn->cn_zoned)
484 		clp->cl_haszonedchild = B_TRUE;
485 
486 	uu_avl_node_init(cn, &cn->cn_treenode, clp->cl_pool);
487 
488 	if (uu_avl_find(clp->cl_tree, cn, NULL, &idx) == NULL) {
489 		uu_avl_insert(clp->cl_tree, cn, idx);
490 	} else {
491 		free(cn);
492 		zfs_close(zhp);
493 	}
494 
495 	return (0);
496 }
497 
498 static int
change_one(zfs_handle_t * zhp,void * data)499 change_one(zfs_handle_t *zhp, void *data)
500 {
501 	prop_changelist_t *clp = data;
502 	char property[ZFS_MAXPROPLEN];
503 	char where[64];
504 	prop_changenode_t *cn = NULL;
505 	zprop_source_t sourcetype = ZPROP_SRC_NONE;
506 	zprop_source_t share_sourcetype = ZPROP_SRC_NONE;
507 	int ret = 0;
508 
509 	/*
510 	 * We only want to unmount/unshare those filesystems that may inherit
511 	 * from the target filesystem.  If we find any filesystem with a
512 	 * locally set mountpoint, we ignore any children since changing the
513 	 * property will not affect them.  If this is a rename, we iterate
514 	 * over all children regardless, since we need them unmounted in
515 	 * order to do the rename.  Also, if this is a volume and we're doing
516 	 * a rename, then always add it to the changelist.
517 	 */
518 
519 	if (!(ZFS_IS_VOLUME(zhp) && clp->cl_realprop == ZFS_PROP_NAME) &&
520 	    zfs_prop_get(zhp, clp->cl_prop, property,
521 	    sizeof (property), &sourcetype, where, sizeof (where),
522 	    B_FALSE) != 0) {
523 		goto out;
524 	}
525 
526 	/*
527 	 * If we are "watching" sharenfs or sharesmb
528 	 * then check out the companion property which is tracked
529 	 * in cl_shareprop
530 	 */
531 	if (clp->cl_shareprop != ZPROP_INVAL &&
532 	    zfs_prop_get(zhp, clp->cl_shareprop, property,
533 	    sizeof (property), &share_sourcetype, where, sizeof (where),
534 	    B_FALSE) != 0) {
535 		goto out;
536 	}
537 
538 	if (clp->cl_alldependents || clp->cl_allchildren ||
539 	    sourcetype == ZPROP_SRC_DEFAULT ||
540 	    sourcetype == ZPROP_SRC_INHERITED ||
541 	    (clp->cl_shareprop != ZPROP_INVAL &&
542 	    (share_sourcetype == ZPROP_SRC_DEFAULT ||
543 	    share_sourcetype == ZPROP_SRC_INHERITED))) {
544 		cn = zfs_alloc(zfs_get_handle(zhp), sizeof (prop_changenode_t));
545 		cn->cn_handle = zhp;
546 		cn->cn_mounted = (clp->cl_gflags & CL_GATHER_MOUNT_ALWAYS) ||
547 		    zfs_is_mounted(zhp, NULL);
548 		cn->cn_shared = zfs_is_shared(zhp, NULL, NULL);
549 		cn->cn_zoned = zfs_prop_get_int(zhp, ZFS_PROP_ZONED);
550 		cn->cn_needpost = B_TRUE;
551 
552 		/* Indicate if any child is exported to a local zone. */
553 		if (getzoneid() == GLOBAL_ZONEID && cn->cn_zoned)
554 			clp->cl_haszonedchild = B_TRUE;
555 
556 		uu_avl_node_init(cn, &cn->cn_treenode, clp->cl_pool);
557 
558 		uu_avl_index_t idx;
559 
560 		if (uu_avl_find(clp->cl_tree, cn, NULL, &idx) == NULL) {
561 			uu_avl_insert(clp->cl_tree, cn, idx);
562 		} else {
563 			free(cn);
564 			cn = NULL;
565 		}
566 
567 		if (!clp->cl_alldependents) {
568 			if (clp->cl_prop != ZFS_PROP_MOUNTPOINT) {
569 				ret = zfs_iter_filesystems_v2(zhp, 0,
570 				    change_one, data);
571 			} else {
572 				ret = zfs_iter_children_v2(zhp, 0, change_one,
573 				    data);
574 			}
575 		}
576 
577 		/*
578 		 * If we added the handle to the changelist, we will re-use it
579 		 * later so return without closing it.
580 		 */
581 		if (cn != NULL)
582 			return (ret);
583 	}
584 
585 out:
586 	zfs_close(zhp);
587 	return (ret);
588 }
589 
590 static int
compare_props(const void * a,const void * b,zfs_prop_t prop)591 compare_props(const void *a, const void *b, zfs_prop_t prop)
592 {
593 	const prop_changenode_t *ca = a;
594 	const prop_changenode_t *cb = b;
595 
596 	char propa[MAXPATHLEN];
597 	char propb[MAXPATHLEN];
598 
599 	boolean_t haspropa, haspropb;
600 
601 	haspropa = (zfs_prop_get(ca->cn_handle, prop, propa, sizeof (propa),
602 	    NULL, NULL, 0, B_FALSE) == 0);
603 	haspropb = (zfs_prop_get(cb->cn_handle, prop, propb, sizeof (propb),
604 	    NULL, NULL, 0, B_FALSE) == 0);
605 
606 	if (!haspropa && haspropb)
607 		return (-1);
608 	else if (haspropa && !haspropb)
609 		return (1);
610 	else if (!haspropa && !haspropb)
611 		return (0);
612 	else
613 		return (strcmp(propb, propa));
614 }
615 
616 static int
compare_mountpoints(const void * a,const void * b,void * unused)617 compare_mountpoints(const void *a, const void *b, void *unused)
618 {
619 	/*
620 	 * When unsharing or unmounting filesystems, we need to do it in
621 	 * mountpoint order.  This allows the user to have a mountpoint
622 	 * hierarchy that is different from the dataset hierarchy, and still
623 	 * allow it to be changed.
624 	 */
625 	(void) unused;
626 	return (compare_props(a, b, ZFS_PROP_MOUNTPOINT));
627 }
628 
629 static int
compare_dataset_names(const void * a,const void * b,void * unused)630 compare_dataset_names(const void *a, const void *b, void *unused)
631 {
632 	(void) unused;
633 	return (compare_props(a, b, ZFS_PROP_NAME));
634 }
635 
636 /*
637  * Given a ZFS handle and a property, construct a complete list of datasets
638  * that need to be modified as part of this process.  For anything but the
639  * 'mountpoint' and 'sharenfs' properties, this just returns an empty list.
640  * Otherwise, we iterate over all children and look for any datasets that
641  * inherit the property.  For each such dataset, we add it to the list and
642  * mark whether it was shared beforehand.
643  */
644 prop_changelist_t *
changelist_gather(zfs_handle_t * zhp,zfs_prop_t prop,int gather_flags,int mnt_flags)645 changelist_gather(zfs_handle_t *zhp, zfs_prop_t prop, int gather_flags,
646     int mnt_flags)
647 {
648 	prop_changelist_t *clp;
649 	prop_changenode_t *cn;
650 	zfs_handle_t *temp;
651 	char property[ZFS_MAXPROPLEN];
652 	boolean_t legacy = B_FALSE;
653 
654 	clp = zfs_alloc(zhp->zfs_hdl, sizeof (prop_changelist_t));
655 
656 	/*
657 	 * For mountpoint-related tasks, we want to sort everything by
658 	 * mountpoint, so that we mount and unmount them in the appropriate
659 	 * order, regardless of their position in the hierarchy.
660 	 */
661 	if (prop == ZFS_PROP_NAME || prop == ZFS_PROP_ZONED ||
662 	    prop == ZFS_PROP_MOUNTPOINT || prop == ZFS_PROP_SHARENFS ||
663 	    prop == ZFS_PROP_SHARESMB) {
664 
665 		if (zfs_prop_get(zhp, ZFS_PROP_MOUNTPOINT,
666 		    property, sizeof (property),
667 		    NULL, NULL, 0, B_FALSE) == 0 &&
668 		    (strcmp(property, "legacy") == 0 ||
669 		    strcmp(property, "none") == 0)) {
670 			legacy = B_TRUE;
671 		}
672 	}
673 
674 	clp->cl_pool = uu_avl_pool_create("changelist_pool",
675 	    sizeof (prop_changenode_t),
676 	    offsetof(prop_changenode_t, cn_treenode),
677 	    legacy ? compare_dataset_names : compare_mountpoints, 0);
678 	if (clp->cl_pool == NULL) {
679 		assert(uu_error() == UU_ERROR_NO_MEMORY);
680 		(void) zfs_error(zhp->zfs_hdl, EZFS_NOMEM, "internal error");
681 		changelist_free(clp);
682 		return (NULL);
683 	}
684 
685 	clp->cl_tree = uu_avl_create(clp->cl_pool, NULL, UU_DEFAULT);
686 	clp->cl_gflags = gather_flags;
687 	clp->cl_mflags = mnt_flags;
688 
689 	if (clp->cl_tree == NULL) {
690 		assert(uu_error() == UU_ERROR_NO_MEMORY);
691 		(void) zfs_error(zhp->zfs_hdl, EZFS_NOMEM, "internal error");
692 		changelist_free(clp);
693 		return (NULL);
694 	}
695 
696 	/*
697 	 * If this is a rename or the 'zoned' property, we pretend we're
698 	 * changing the mountpoint and flag it so we can catch all children in
699 	 * change_one().
700 	 *
701 	 * Flag cl_alldependents to catch all children plus the dependents
702 	 * (clones) that are not in the hierarchy.
703 	 */
704 	if (prop == ZFS_PROP_NAME) {
705 		clp->cl_prop = ZFS_PROP_MOUNTPOINT;
706 		clp->cl_alldependents = B_TRUE;
707 	} else if (prop == ZFS_PROP_ZONED) {
708 		clp->cl_prop = ZFS_PROP_MOUNTPOINT;
709 		clp->cl_allchildren = B_TRUE;
710 	} else if (prop == ZFS_PROP_CANMOUNT) {
711 		clp->cl_prop = ZFS_PROP_MOUNTPOINT;
712 	} else if (prop == ZFS_PROP_VOLSIZE) {
713 		clp->cl_prop = ZFS_PROP_MOUNTPOINT;
714 	} else {
715 		clp->cl_prop = prop;
716 	}
717 	clp->cl_realprop = prop;
718 
719 	if (clp->cl_prop != ZFS_PROP_MOUNTPOINT &&
720 	    clp->cl_prop != ZFS_PROP_SHARENFS &&
721 	    clp->cl_prop != ZFS_PROP_SHARESMB)
722 		return (clp);
723 
724 	/*
725 	 * If watching SHARENFS or SHARESMB then
726 	 * also watch its companion property.
727 	 */
728 	if (clp->cl_prop == ZFS_PROP_SHARENFS)
729 		clp->cl_shareprop = ZFS_PROP_SHARESMB;
730 	else if (clp->cl_prop == ZFS_PROP_SHARESMB)
731 		clp->cl_shareprop = ZFS_PROP_SHARENFS;
732 
733 	if (clp->cl_prop == ZFS_PROP_MOUNTPOINT &&
734 	    (clp->cl_gflags & CL_GATHER_ITER_MOUNTED)) {
735 		/*
736 		 * Instead of iterating through all of the dataset children we
737 		 * gather mounted dataset children from MNTTAB
738 		 */
739 		if (zfs_iter_mounted(zhp, changelist_add_mounted, clp) != 0) {
740 			changelist_free(clp);
741 			return (NULL);
742 		}
743 	} else if (clp->cl_alldependents) {
744 		if (zfs_iter_dependents_v2(zhp, 0, B_TRUE, change_one,
745 		    clp) != 0) {
746 			changelist_free(clp);
747 			return (NULL);
748 		}
749 	} else if (clp->cl_prop != ZFS_PROP_MOUNTPOINT) {
750 		if (zfs_iter_filesystems_v2(zhp, 0, change_one, clp) != 0) {
751 			changelist_free(clp);
752 			return (NULL);
753 		}
754 	} else if (zfs_iter_children_v2(zhp, 0, change_one, clp) != 0) {
755 		changelist_free(clp);
756 		return (NULL);
757 	}
758 
759 	/*
760 	 * We have to re-open ourselves because we auto-close all the handles
761 	 * and can't tell the difference.
762 	 */
763 	if ((temp = zfs_open(zhp->zfs_hdl, zfs_get_name(zhp),
764 	    ZFS_TYPE_DATASET)) == NULL) {
765 		changelist_free(clp);
766 		return (NULL);
767 	}
768 
769 	/*
770 	 * Always add ourself to the list.  We add ourselves to the end so that
771 	 * we're the last to be unmounted.
772 	 */
773 	cn = zfs_alloc(zhp->zfs_hdl, sizeof (prop_changenode_t));
774 	cn->cn_handle = temp;
775 	cn->cn_mounted = (clp->cl_gflags & CL_GATHER_MOUNT_ALWAYS) ||
776 	    zfs_is_mounted(temp, NULL);
777 	cn->cn_shared = zfs_is_shared(temp, NULL, NULL);
778 	cn->cn_zoned = zfs_prop_get_int(zhp, ZFS_PROP_ZONED);
779 	cn->cn_needpost = B_TRUE;
780 
781 	uu_avl_node_init(cn, &cn->cn_treenode, clp->cl_pool);
782 	uu_avl_index_t idx;
783 	if (uu_avl_find(clp->cl_tree, cn, NULL, &idx) == NULL) {
784 		uu_avl_insert(clp->cl_tree, cn, idx);
785 	} else {
786 		free(cn);
787 		zfs_close(temp);
788 	}
789 
790 	/*
791 	 * If the mountpoint property was previously 'legacy', or 'none',
792 	 * record it as the behavior of changelist_postfix() will be different.
793 	 */
794 	if ((clp->cl_prop == ZFS_PROP_MOUNTPOINT) && legacy) {
795 		/*
796 		 * do not automatically mount ex-legacy datasets if
797 		 * we specifically set canmount to noauto
798 		 */
799 		if (zfs_prop_get_int(zhp, ZFS_PROP_CANMOUNT) !=
800 		    ZFS_CANMOUNT_NOAUTO)
801 			clp->cl_waslegacy = B_TRUE;
802 	}
803 
804 	return (clp);
805 }
806