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 https://opensource.org/licenses/CDDL-1.0.
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  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23  * Copyright (c) 2012, 2018 by Delphix. All rights reserved.
24  */
25 
26 /* Portions Copyright 2010 Robert Milkowski */
27 
28 #include <sys/types.h>
29 #include <sys/param.h>
30 #include <sys/sysmacros.h>
31 #include <sys/kmem.h>
32 #include <sys/pathname.h>
33 #include <sys/vnode.h>
34 #include <sys/vfs.h>
35 #include <sys/mntent.h>
36 #include <sys/cmn_err.h>
37 #include <sys/zfs_znode.h>
38 #include <sys/zfs_vnops.h>
39 #include <sys/zfs_dir.h>
40 #include <sys/zil.h>
41 #include <sys/fs/zfs.h>
42 #include <sys/dmu.h>
43 #include <sys/dsl_prop.h>
44 #include <sys/dsl_dataset.h>
45 #include <sys/dsl_deleg.h>
46 #include <sys/spa.h>
47 #include <sys/zap.h>
48 #include <sys/sa.h>
49 #include <sys/sa_impl.h>
50 #include <sys/policy.h>
51 #include <sys/atomic.h>
52 #include <sys/zfs_ioctl.h>
53 #include <sys/zfs_ctldir.h>
54 #include <sys/zfs_fuid.h>
55 #include <sys/zfs_quota.h>
56 #include <sys/sunddi.h>
57 #include <sys/dmu_objset.h>
58 #include <sys/dsl_dir.h>
59 #include <sys/objlist.h>
60 #include <sys/zpl.h>
61 #include <linux/vfs_compat.h>
62 #include "zfs_comutil.h"
63 
64 enum {
65 	TOKEN_RO,
66 	TOKEN_RW,
67 	TOKEN_SETUID,
68 	TOKEN_NOSETUID,
69 	TOKEN_EXEC,
70 	TOKEN_NOEXEC,
71 	TOKEN_DEVICES,
72 	TOKEN_NODEVICES,
73 	TOKEN_DIRXATTR,
74 	TOKEN_SAXATTR,
75 	TOKEN_XATTR,
76 	TOKEN_NOXATTR,
77 	TOKEN_ATIME,
78 	TOKEN_NOATIME,
79 	TOKEN_RELATIME,
80 	TOKEN_NORELATIME,
81 	TOKEN_NBMAND,
82 	TOKEN_NONBMAND,
83 	TOKEN_MNTPOINT,
84 	TOKEN_LAST,
85 };
86 
87 static const match_table_t zpl_tokens = {
88 	{ TOKEN_RO,		MNTOPT_RO },
89 	{ TOKEN_RW,		MNTOPT_RW },
90 	{ TOKEN_SETUID,		MNTOPT_SETUID },
91 	{ TOKEN_NOSETUID,	MNTOPT_NOSETUID },
92 	{ TOKEN_EXEC,		MNTOPT_EXEC },
93 	{ TOKEN_NOEXEC,		MNTOPT_NOEXEC },
94 	{ TOKEN_DEVICES,	MNTOPT_DEVICES },
95 	{ TOKEN_NODEVICES,	MNTOPT_NODEVICES },
96 	{ TOKEN_DIRXATTR,	MNTOPT_DIRXATTR },
97 	{ TOKEN_SAXATTR,	MNTOPT_SAXATTR },
98 	{ TOKEN_XATTR,		MNTOPT_XATTR },
99 	{ TOKEN_NOXATTR,	MNTOPT_NOXATTR },
100 	{ TOKEN_ATIME,		MNTOPT_ATIME },
101 	{ TOKEN_NOATIME,	MNTOPT_NOATIME },
102 	{ TOKEN_RELATIME,	MNTOPT_RELATIME },
103 	{ TOKEN_NORELATIME,	MNTOPT_NORELATIME },
104 	{ TOKEN_NBMAND,		MNTOPT_NBMAND },
105 	{ TOKEN_NONBMAND,	MNTOPT_NONBMAND },
106 	{ TOKEN_MNTPOINT,	MNTOPT_MNTPOINT "=%s" },
107 	{ TOKEN_LAST,		NULL },
108 };
109 
110 static void
111 zfsvfs_vfs_free(vfs_t *vfsp)
112 {
113 	if (vfsp != NULL) {
114 		if (vfsp->vfs_mntpoint != NULL)
115 			kmem_strfree(vfsp->vfs_mntpoint);
116 
117 		kmem_free(vfsp, sizeof (vfs_t));
118 	}
119 }
120 
121 static int
122 zfsvfs_parse_option(char *option, int token, substring_t *args, vfs_t *vfsp)
123 {
124 	switch (token) {
125 	case TOKEN_RO:
126 		vfsp->vfs_readonly = B_TRUE;
127 		vfsp->vfs_do_readonly = B_TRUE;
128 		break;
129 	case TOKEN_RW:
130 		vfsp->vfs_readonly = B_FALSE;
131 		vfsp->vfs_do_readonly = B_TRUE;
132 		break;
133 	case TOKEN_SETUID:
134 		vfsp->vfs_setuid = B_TRUE;
135 		vfsp->vfs_do_setuid = B_TRUE;
136 		break;
137 	case TOKEN_NOSETUID:
138 		vfsp->vfs_setuid = B_FALSE;
139 		vfsp->vfs_do_setuid = B_TRUE;
140 		break;
141 	case TOKEN_EXEC:
142 		vfsp->vfs_exec = B_TRUE;
143 		vfsp->vfs_do_exec = B_TRUE;
144 		break;
145 	case TOKEN_NOEXEC:
146 		vfsp->vfs_exec = B_FALSE;
147 		vfsp->vfs_do_exec = B_TRUE;
148 		break;
149 	case TOKEN_DEVICES:
150 		vfsp->vfs_devices = B_TRUE;
151 		vfsp->vfs_do_devices = B_TRUE;
152 		break;
153 	case TOKEN_NODEVICES:
154 		vfsp->vfs_devices = B_FALSE;
155 		vfsp->vfs_do_devices = B_TRUE;
156 		break;
157 	case TOKEN_DIRXATTR:
158 		vfsp->vfs_xattr = ZFS_XATTR_DIR;
159 		vfsp->vfs_do_xattr = B_TRUE;
160 		break;
161 	case TOKEN_SAXATTR:
162 		vfsp->vfs_xattr = ZFS_XATTR_SA;
163 		vfsp->vfs_do_xattr = B_TRUE;
164 		break;
165 	case TOKEN_XATTR:
166 		vfsp->vfs_xattr = ZFS_XATTR_DIR;
167 		vfsp->vfs_do_xattr = B_TRUE;
168 		break;
169 	case TOKEN_NOXATTR:
170 		vfsp->vfs_xattr = ZFS_XATTR_OFF;
171 		vfsp->vfs_do_xattr = B_TRUE;
172 		break;
173 	case TOKEN_ATIME:
174 		vfsp->vfs_atime = B_TRUE;
175 		vfsp->vfs_do_atime = B_TRUE;
176 		break;
177 	case TOKEN_NOATIME:
178 		vfsp->vfs_atime = B_FALSE;
179 		vfsp->vfs_do_atime = B_TRUE;
180 		break;
181 	case TOKEN_RELATIME:
182 		vfsp->vfs_relatime = B_TRUE;
183 		vfsp->vfs_do_relatime = B_TRUE;
184 		break;
185 	case TOKEN_NORELATIME:
186 		vfsp->vfs_relatime = B_FALSE;
187 		vfsp->vfs_do_relatime = B_TRUE;
188 		break;
189 	case TOKEN_NBMAND:
190 		vfsp->vfs_nbmand = B_TRUE;
191 		vfsp->vfs_do_nbmand = B_TRUE;
192 		break;
193 	case TOKEN_NONBMAND:
194 		vfsp->vfs_nbmand = B_FALSE;
195 		vfsp->vfs_do_nbmand = B_TRUE;
196 		break;
197 	case TOKEN_MNTPOINT:
198 		vfsp->vfs_mntpoint = match_strdup(&args[0]);
199 		if (vfsp->vfs_mntpoint == NULL)
200 			return (SET_ERROR(ENOMEM));
201 
202 		break;
203 	default:
204 		break;
205 	}
206 
207 	return (0);
208 }
209 
210 /*
211  * Parse the raw mntopts and return a vfs_t describing the options.
212  */
213 static int
214 zfsvfs_parse_options(char *mntopts, vfs_t **vfsp)
215 {
216 	vfs_t *tmp_vfsp;
217 	int error;
218 
219 	tmp_vfsp = kmem_zalloc(sizeof (vfs_t), KM_SLEEP);
220 
221 	if (mntopts != NULL) {
222 		substring_t args[MAX_OPT_ARGS];
223 		char *tmp_mntopts, *p, *t;
224 		int token;
225 
226 		tmp_mntopts = t = kmem_strdup(mntopts);
227 		if (tmp_mntopts == NULL)
228 			return (SET_ERROR(ENOMEM));
229 
230 		while ((p = strsep(&t, ",")) != NULL) {
231 			if (!*p)
232 				continue;
233 
234 			args[0].to = args[0].from = NULL;
235 			token = match_token(p, zpl_tokens, args);
236 			error = zfsvfs_parse_option(p, token, args, tmp_vfsp);
237 			if (error) {
238 				kmem_strfree(tmp_mntopts);
239 				zfsvfs_vfs_free(tmp_vfsp);
240 				return (error);
241 			}
242 		}
243 
244 		kmem_strfree(tmp_mntopts);
245 	}
246 
247 	*vfsp = tmp_vfsp;
248 
249 	return (0);
250 }
251 
252 boolean_t
253 zfs_is_readonly(zfsvfs_t *zfsvfs)
254 {
255 	return (!!(zfsvfs->z_sb->s_flags & SB_RDONLY));
256 }
257 
258 int
259 zfs_sync(struct super_block *sb, int wait, cred_t *cr)
260 {
261 	(void) cr;
262 	zfsvfs_t *zfsvfs = sb->s_fs_info;
263 
264 	/*
265 	 * Semantically, the only requirement is that the sync be initiated.
266 	 * The DMU syncs out txgs frequently, so there's nothing to do.
267 	 */
268 	if (!wait)
269 		return (0);
270 
271 	if (zfsvfs != NULL) {
272 		/*
273 		 * Sync a specific filesystem.
274 		 */
275 		dsl_pool_t *dp;
276 		int error;
277 
278 		if ((error = zfs_enter(zfsvfs, FTAG)) != 0)
279 			return (error);
280 		dp = dmu_objset_pool(zfsvfs->z_os);
281 
282 		/*
283 		 * If the system is shutting down, then skip any
284 		 * filesystems which may exist on a suspended pool.
285 		 */
286 		if (spa_suspended(dp->dp_spa)) {
287 			zfs_exit(zfsvfs, FTAG);
288 			return (0);
289 		}
290 
291 		if (zfsvfs->z_log != NULL)
292 			zil_commit(zfsvfs->z_log, 0);
293 
294 		zfs_exit(zfsvfs, FTAG);
295 	} else {
296 		/*
297 		 * Sync all ZFS filesystems.  This is what happens when you
298 		 * run sync(1).  Unlike other filesystems, ZFS honors the
299 		 * request by waiting for all pools to commit all dirty data.
300 		 */
301 		spa_sync_allpools();
302 	}
303 
304 	return (0);
305 }
306 
307 static void
308 atime_changed_cb(void *arg, uint64_t newval)
309 {
310 	zfsvfs_t *zfsvfs = arg;
311 	struct super_block *sb = zfsvfs->z_sb;
312 
313 	if (sb == NULL)
314 		return;
315 	/*
316 	 * Update SB_NOATIME bit in VFS super block.  Since atime update is
317 	 * determined by atime_needs_update(), atime_needs_update() needs to
318 	 * return false if atime is turned off, and not unconditionally return
319 	 * false if atime is turned on.
320 	 */
321 	if (newval)
322 		sb->s_flags &= ~SB_NOATIME;
323 	else
324 		sb->s_flags |= SB_NOATIME;
325 }
326 
327 static void
328 relatime_changed_cb(void *arg, uint64_t newval)
329 {
330 	((zfsvfs_t *)arg)->z_relatime = newval;
331 }
332 
333 static void
334 xattr_changed_cb(void *arg, uint64_t newval)
335 {
336 	zfsvfs_t *zfsvfs = arg;
337 
338 	if (newval == ZFS_XATTR_OFF) {
339 		zfsvfs->z_flags &= ~ZSB_XATTR;
340 	} else {
341 		zfsvfs->z_flags |= ZSB_XATTR;
342 
343 		if (newval == ZFS_XATTR_SA)
344 			zfsvfs->z_xattr_sa = B_TRUE;
345 		else
346 			zfsvfs->z_xattr_sa = B_FALSE;
347 	}
348 }
349 
350 static void
351 acltype_changed_cb(void *arg, uint64_t newval)
352 {
353 	zfsvfs_t *zfsvfs = arg;
354 
355 	switch (newval) {
356 	case ZFS_ACLTYPE_NFSV4:
357 	case ZFS_ACLTYPE_OFF:
358 		zfsvfs->z_acl_type = ZFS_ACLTYPE_OFF;
359 		zfsvfs->z_sb->s_flags &= ~SB_POSIXACL;
360 		break;
361 	case ZFS_ACLTYPE_POSIX:
362 #ifdef CONFIG_FS_POSIX_ACL
363 		zfsvfs->z_acl_type = ZFS_ACLTYPE_POSIX;
364 		zfsvfs->z_sb->s_flags |= SB_POSIXACL;
365 #else
366 		zfsvfs->z_acl_type = ZFS_ACLTYPE_OFF;
367 		zfsvfs->z_sb->s_flags &= ~SB_POSIXACL;
368 #endif /* CONFIG_FS_POSIX_ACL */
369 		break;
370 	default:
371 		break;
372 	}
373 }
374 
375 static void
376 blksz_changed_cb(void *arg, uint64_t newval)
377 {
378 	zfsvfs_t *zfsvfs = arg;
379 	ASSERT3U(newval, <=, spa_maxblocksize(dmu_objset_spa(zfsvfs->z_os)));
380 	ASSERT3U(newval, >=, SPA_MINBLOCKSIZE);
381 	ASSERT(ISP2(newval));
382 
383 	zfsvfs->z_max_blksz = newval;
384 }
385 
386 static void
387 readonly_changed_cb(void *arg, uint64_t newval)
388 {
389 	zfsvfs_t *zfsvfs = arg;
390 	struct super_block *sb = zfsvfs->z_sb;
391 
392 	if (sb == NULL)
393 		return;
394 
395 	if (newval)
396 		sb->s_flags |= SB_RDONLY;
397 	else
398 		sb->s_flags &= ~SB_RDONLY;
399 }
400 
401 static void
402 devices_changed_cb(void *arg, uint64_t newval)
403 {
404 }
405 
406 static void
407 setuid_changed_cb(void *arg, uint64_t newval)
408 {
409 }
410 
411 static void
412 exec_changed_cb(void *arg, uint64_t newval)
413 {
414 }
415 
416 static void
417 nbmand_changed_cb(void *arg, uint64_t newval)
418 {
419 	zfsvfs_t *zfsvfs = arg;
420 	struct super_block *sb = zfsvfs->z_sb;
421 
422 	if (sb == NULL)
423 		return;
424 
425 	if (newval == TRUE)
426 		sb->s_flags |= SB_MANDLOCK;
427 	else
428 		sb->s_flags &= ~SB_MANDLOCK;
429 }
430 
431 static void
432 snapdir_changed_cb(void *arg, uint64_t newval)
433 {
434 	((zfsvfs_t *)arg)->z_show_ctldir = newval;
435 }
436 
437 static void
438 acl_mode_changed_cb(void *arg, uint64_t newval)
439 {
440 	zfsvfs_t *zfsvfs = arg;
441 
442 	zfsvfs->z_acl_mode = newval;
443 }
444 
445 static void
446 acl_inherit_changed_cb(void *arg, uint64_t newval)
447 {
448 	((zfsvfs_t *)arg)->z_acl_inherit = newval;
449 }
450 
451 static int
452 zfs_register_callbacks(vfs_t *vfsp)
453 {
454 	struct dsl_dataset *ds = NULL;
455 	objset_t *os = NULL;
456 	zfsvfs_t *zfsvfs = NULL;
457 	int error = 0;
458 
459 	ASSERT(vfsp);
460 	zfsvfs = vfsp->vfs_data;
461 	ASSERT(zfsvfs);
462 	os = zfsvfs->z_os;
463 
464 	/*
465 	 * The act of registering our callbacks will destroy any mount
466 	 * options we may have.  In order to enable temporary overrides
467 	 * of mount options, we stash away the current values and
468 	 * restore them after we register the callbacks.
469 	 */
470 	if (zfs_is_readonly(zfsvfs) || !spa_writeable(dmu_objset_spa(os))) {
471 		vfsp->vfs_do_readonly = B_TRUE;
472 		vfsp->vfs_readonly = B_TRUE;
473 	}
474 
475 	/*
476 	 * Register property callbacks.
477 	 *
478 	 * It would probably be fine to just check for i/o error from
479 	 * the first prop_register(), but I guess I like to go
480 	 * overboard...
481 	 */
482 	ds = dmu_objset_ds(os);
483 	dsl_pool_config_enter(dmu_objset_pool(os), FTAG);
484 	error = dsl_prop_register(ds,
485 	    zfs_prop_to_name(ZFS_PROP_ATIME), atime_changed_cb, zfsvfs);
486 	error = error ? error : dsl_prop_register(ds,
487 	    zfs_prop_to_name(ZFS_PROP_RELATIME), relatime_changed_cb, zfsvfs);
488 	error = error ? error : dsl_prop_register(ds,
489 	    zfs_prop_to_name(ZFS_PROP_XATTR), xattr_changed_cb, zfsvfs);
490 	error = error ? error : dsl_prop_register(ds,
491 	    zfs_prop_to_name(ZFS_PROP_RECORDSIZE), blksz_changed_cb, zfsvfs);
492 	error = error ? error : dsl_prop_register(ds,
493 	    zfs_prop_to_name(ZFS_PROP_READONLY), readonly_changed_cb, zfsvfs);
494 	error = error ? error : dsl_prop_register(ds,
495 	    zfs_prop_to_name(ZFS_PROP_DEVICES), devices_changed_cb, zfsvfs);
496 	error = error ? error : dsl_prop_register(ds,
497 	    zfs_prop_to_name(ZFS_PROP_SETUID), setuid_changed_cb, zfsvfs);
498 	error = error ? error : dsl_prop_register(ds,
499 	    zfs_prop_to_name(ZFS_PROP_EXEC), exec_changed_cb, zfsvfs);
500 	error = error ? error : dsl_prop_register(ds,
501 	    zfs_prop_to_name(ZFS_PROP_SNAPDIR), snapdir_changed_cb, zfsvfs);
502 	error = error ? error : dsl_prop_register(ds,
503 	    zfs_prop_to_name(ZFS_PROP_ACLTYPE), acltype_changed_cb, zfsvfs);
504 	error = error ? error : dsl_prop_register(ds,
505 	    zfs_prop_to_name(ZFS_PROP_ACLMODE), acl_mode_changed_cb, zfsvfs);
506 	error = error ? error : dsl_prop_register(ds,
507 	    zfs_prop_to_name(ZFS_PROP_ACLINHERIT), acl_inherit_changed_cb,
508 	    zfsvfs);
509 	error = error ? error : dsl_prop_register(ds,
510 	    zfs_prop_to_name(ZFS_PROP_NBMAND), nbmand_changed_cb, zfsvfs);
511 	dsl_pool_config_exit(dmu_objset_pool(os), FTAG);
512 	if (error)
513 		goto unregister;
514 
515 	/*
516 	 * Invoke our callbacks to restore temporary mount options.
517 	 */
518 	if (vfsp->vfs_do_readonly)
519 		readonly_changed_cb(zfsvfs, vfsp->vfs_readonly);
520 	if (vfsp->vfs_do_setuid)
521 		setuid_changed_cb(zfsvfs, vfsp->vfs_setuid);
522 	if (vfsp->vfs_do_exec)
523 		exec_changed_cb(zfsvfs, vfsp->vfs_exec);
524 	if (vfsp->vfs_do_devices)
525 		devices_changed_cb(zfsvfs, vfsp->vfs_devices);
526 	if (vfsp->vfs_do_xattr)
527 		xattr_changed_cb(zfsvfs, vfsp->vfs_xattr);
528 	if (vfsp->vfs_do_atime)
529 		atime_changed_cb(zfsvfs, vfsp->vfs_atime);
530 	if (vfsp->vfs_do_relatime)
531 		relatime_changed_cb(zfsvfs, vfsp->vfs_relatime);
532 	if (vfsp->vfs_do_nbmand)
533 		nbmand_changed_cb(zfsvfs, vfsp->vfs_nbmand);
534 
535 	return (0);
536 
537 unregister:
538 	dsl_prop_unregister_all(ds, zfsvfs);
539 	return (error);
540 }
541 
542 /*
543  * Takes a dataset, a property, a value and that value's setpoint as
544  * found in the ZAP. Checks if the property has been changed in the vfs.
545  * If so, val and setpoint will be overwritten with updated content.
546  * Otherwise, they are left unchanged.
547  */
548 int
549 zfs_get_temporary_prop(dsl_dataset_t *ds, zfs_prop_t zfs_prop, uint64_t *val,
550     char *setpoint)
551 {
552 	int error;
553 	zfsvfs_t *zfvp;
554 	vfs_t *vfsp;
555 	objset_t *os;
556 	uint64_t tmp = *val;
557 
558 	error = dmu_objset_from_ds(ds, &os);
559 	if (error != 0)
560 		return (error);
561 
562 	if (dmu_objset_type(os) != DMU_OST_ZFS)
563 		return (EINVAL);
564 
565 	mutex_enter(&os->os_user_ptr_lock);
566 	zfvp = dmu_objset_get_user(os);
567 	mutex_exit(&os->os_user_ptr_lock);
568 	if (zfvp == NULL)
569 		return (ESRCH);
570 
571 	vfsp = zfvp->z_vfs;
572 
573 	switch (zfs_prop) {
574 	case ZFS_PROP_ATIME:
575 		if (vfsp->vfs_do_atime)
576 			tmp = vfsp->vfs_atime;
577 		break;
578 	case ZFS_PROP_RELATIME:
579 		if (vfsp->vfs_do_relatime)
580 			tmp = vfsp->vfs_relatime;
581 		break;
582 	case ZFS_PROP_DEVICES:
583 		if (vfsp->vfs_do_devices)
584 			tmp = vfsp->vfs_devices;
585 		break;
586 	case ZFS_PROP_EXEC:
587 		if (vfsp->vfs_do_exec)
588 			tmp = vfsp->vfs_exec;
589 		break;
590 	case ZFS_PROP_SETUID:
591 		if (vfsp->vfs_do_setuid)
592 			tmp = vfsp->vfs_setuid;
593 		break;
594 	case ZFS_PROP_READONLY:
595 		if (vfsp->vfs_do_readonly)
596 			tmp = vfsp->vfs_readonly;
597 		break;
598 	case ZFS_PROP_XATTR:
599 		if (vfsp->vfs_do_xattr)
600 			tmp = vfsp->vfs_xattr;
601 		break;
602 	case ZFS_PROP_NBMAND:
603 		if (vfsp->vfs_do_nbmand)
604 			tmp = vfsp->vfs_nbmand;
605 		break;
606 	default:
607 		return (ENOENT);
608 	}
609 
610 	if (tmp != *val) {
611 		(void) strcpy(setpoint, "temporary");
612 		*val = tmp;
613 	}
614 	return (0);
615 }
616 
617 /*
618  * Associate this zfsvfs with the given objset, which must be owned.
619  * This will cache a bunch of on-disk state from the objset in the
620  * zfsvfs.
621  */
622 static int
623 zfsvfs_init(zfsvfs_t *zfsvfs, objset_t *os)
624 {
625 	int error;
626 	uint64_t val;
627 
628 	zfsvfs->z_max_blksz = SPA_OLD_MAXBLOCKSIZE;
629 	zfsvfs->z_show_ctldir = ZFS_SNAPDIR_VISIBLE;
630 	zfsvfs->z_os = os;
631 
632 	error = zfs_get_zplprop(os, ZFS_PROP_VERSION, &zfsvfs->z_version);
633 	if (error != 0)
634 		return (error);
635 	if (zfsvfs->z_version >
636 	    zfs_zpl_version_map(spa_version(dmu_objset_spa(os)))) {
637 		(void) printk("Can't mount a version %lld file system "
638 		    "on a version %lld pool\n. Pool must be upgraded to mount "
639 		    "this file system.\n", (u_longlong_t)zfsvfs->z_version,
640 		    (u_longlong_t)spa_version(dmu_objset_spa(os)));
641 		return (SET_ERROR(ENOTSUP));
642 	}
643 	error = zfs_get_zplprop(os, ZFS_PROP_NORMALIZE, &val);
644 	if (error != 0)
645 		return (error);
646 	zfsvfs->z_norm = (int)val;
647 
648 	error = zfs_get_zplprop(os, ZFS_PROP_UTF8ONLY, &val);
649 	if (error != 0)
650 		return (error);
651 	zfsvfs->z_utf8 = (val != 0);
652 
653 	error = zfs_get_zplprop(os, ZFS_PROP_CASE, &val);
654 	if (error != 0)
655 		return (error);
656 	zfsvfs->z_case = (uint_t)val;
657 
658 	if ((error = zfs_get_zplprop(os, ZFS_PROP_ACLTYPE, &val)) != 0)
659 		return (error);
660 	zfsvfs->z_acl_type = (uint_t)val;
661 
662 	/*
663 	 * Fold case on file systems that are always or sometimes case
664 	 * insensitive.
665 	 */
666 	if (zfsvfs->z_case == ZFS_CASE_INSENSITIVE ||
667 	    zfsvfs->z_case == ZFS_CASE_MIXED)
668 		zfsvfs->z_norm |= U8_TEXTPREP_TOUPPER;
669 
670 	zfsvfs->z_use_fuids = USE_FUIDS(zfsvfs->z_version, zfsvfs->z_os);
671 	zfsvfs->z_use_sa = USE_SA(zfsvfs->z_version, zfsvfs->z_os);
672 
673 	uint64_t sa_obj = 0;
674 	if (zfsvfs->z_use_sa) {
675 		/* should either have both of these objects or none */
676 		error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_SA_ATTRS, 8, 1,
677 		    &sa_obj);
678 		if (error != 0)
679 			return (error);
680 
681 		error = zfs_get_zplprop(os, ZFS_PROP_XATTR, &val);
682 		if ((error == 0) && (val == ZFS_XATTR_SA))
683 			zfsvfs->z_xattr_sa = B_TRUE;
684 	}
685 
686 	error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_ROOT_OBJ, 8, 1,
687 	    &zfsvfs->z_root);
688 	if (error != 0)
689 		return (error);
690 	ASSERT(zfsvfs->z_root != 0);
691 
692 	error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_UNLINKED_SET, 8, 1,
693 	    &zfsvfs->z_unlinkedobj);
694 	if (error != 0)
695 		return (error);
696 
697 	error = zap_lookup(os, MASTER_NODE_OBJ,
698 	    zfs_userquota_prop_prefixes[ZFS_PROP_USERQUOTA],
699 	    8, 1, &zfsvfs->z_userquota_obj);
700 	if (error == ENOENT)
701 		zfsvfs->z_userquota_obj = 0;
702 	else if (error != 0)
703 		return (error);
704 
705 	error = zap_lookup(os, MASTER_NODE_OBJ,
706 	    zfs_userquota_prop_prefixes[ZFS_PROP_GROUPQUOTA],
707 	    8, 1, &zfsvfs->z_groupquota_obj);
708 	if (error == ENOENT)
709 		zfsvfs->z_groupquota_obj = 0;
710 	else if (error != 0)
711 		return (error);
712 
713 	error = zap_lookup(os, MASTER_NODE_OBJ,
714 	    zfs_userquota_prop_prefixes[ZFS_PROP_PROJECTQUOTA],
715 	    8, 1, &zfsvfs->z_projectquota_obj);
716 	if (error == ENOENT)
717 		zfsvfs->z_projectquota_obj = 0;
718 	else if (error != 0)
719 		return (error);
720 
721 	error = zap_lookup(os, MASTER_NODE_OBJ,
722 	    zfs_userquota_prop_prefixes[ZFS_PROP_USEROBJQUOTA],
723 	    8, 1, &zfsvfs->z_userobjquota_obj);
724 	if (error == ENOENT)
725 		zfsvfs->z_userobjquota_obj = 0;
726 	else if (error != 0)
727 		return (error);
728 
729 	error = zap_lookup(os, MASTER_NODE_OBJ,
730 	    zfs_userquota_prop_prefixes[ZFS_PROP_GROUPOBJQUOTA],
731 	    8, 1, &zfsvfs->z_groupobjquota_obj);
732 	if (error == ENOENT)
733 		zfsvfs->z_groupobjquota_obj = 0;
734 	else if (error != 0)
735 		return (error);
736 
737 	error = zap_lookup(os, MASTER_NODE_OBJ,
738 	    zfs_userquota_prop_prefixes[ZFS_PROP_PROJECTOBJQUOTA],
739 	    8, 1, &zfsvfs->z_projectobjquota_obj);
740 	if (error == ENOENT)
741 		zfsvfs->z_projectobjquota_obj = 0;
742 	else if (error != 0)
743 		return (error);
744 
745 	error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_FUID_TABLES, 8, 1,
746 	    &zfsvfs->z_fuid_obj);
747 	if (error == ENOENT)
748 		zfsvfs->z_fuid_obj = 0;
749 	else if (error != 0)
750 		return (error);
751 
752 	error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_SHARES_DIR, 8, 1,
753 	    &zfsvfs->z_shares_dir);
754 	if (error == ENOENT)
755 		zfsvfs->z_shares_dir = 0;
756 	else if (error != 0)
757 		return (error);
758 
759 	error = sa_setup(os, sa_obj, zfs_attr_table, ZPL_END,
760 	    &zfsvfs->z_attr_table);
761 	if (error != 0)
762 		return (error);
763 
764 	if (zfsvfs->z_version >= ZPL_VERSION_SA)
765 		sa_register_update_callback(os, zfs_sa_upgrade);
766 
767 	return (0);
768 }
769 
770 int
771 zfsvfs_create(const char *osname, boolean_t readonly, zfsvfs_t **zfvp)
772 {
773 	objset_t *os;
774 	zfsvfs_t *zfsvfs;
775 	int error;
776 	boolean_t ro = (readonly || (strchr(osname, '@') != NULL));
777 
778 	zfsvfs = kmem_zalloc(sizeof (zfsvfs_t), KM_SLEEP);
779 
780 	error = dmu_objset_own(osname, DMU_OST_ZFS, ro, B_TRUE, zfsvfs, &os);
781 	if (error != 0) {
782 		kmem_free(zfsvfs, sizeof (zfsvfs_t));
783 		return (error);
784 	}
785 
786 	error = zfsvfs_create_impl(zfvp, zfsvfs, os);
787 
788 	return (error);
789 }
790 
791 
792 /*
793  * Note: zfsvfs is assumed to be malloc'd, and will be freed by this function
794  * on a failure.  Do not pass in a statically allocated zfsvfs.
795  */
796 int
797 zfsvfs_create_impl(zfsvfs_t **zfvp, zfsvfs_t *zfsvfs, objset_t *os)
798 {
799 	int error;
800 
801 	zfsvfs->z_vfs = NULL;
802 	zfsvfs->z_sb = NULL;
803 	zfsvfs->z_parent = zfsvfs;
804 
805 	mutex_init(&zfsvfs->z_znodes_lock, NULL, MUTEX_DEFAULT, NULL);
806 	mutex_init(&zfsvfs->z_lock, NULL, MUTEX_DEFAULT, NULL);
807 	list_create(&zfsvfs->z_all_znodes, sizeof (znode_t),
808 	    offsetof(znode_t, z_link_node));
809 	ZFS_TEARDOWN_INIT(zfsvfs);
810 	rw_init(&zfsvfs->z_teardown_inactive_lock, NULL, RW_DEFAULT, NULL);
811 	rw_init(&zfsvfs->z_fuid_lock, NULL, RW_DEFAULT, NULL);
812 
813 	int size = MIN(1 << (highbit64(zfs_object_mutex_size) - 1),
814 	    ZFS_OBJ_MTX_MAX);
815 	zfsvfs->z_hold_size = size;
816 	zfsvfs->z_hold_trees = vmem_zalloc(sizeof (avl_tree_t) * size,
817 	    KM_SLEEP);
818 	zfsvfs->z_hold_locks = vmem_zalloc(sizeof (kmutex_t) * size, KM_SLEEP);
819 	for (int i = 0; i != size; i++) {
820 		avl_create(&zfsvfs->z_hold_trees[i], zfs_znode_hold_compare,
821 		    sizeof (znode_hold_t), offsetof(znode_hold_t, zh_node));
822 		mutex_init(&zfsvfs->z_hold_locks[i], NULL, MUTEX_DEFAULT, NULL);
823 	}
824 
825 	error = zfsvfs_init(zfsvfs, os);
826 	if (error != 0) {
827 		dmu_objset_disown(os, B_TRUE, zfsvfs);
828 		*zfvp = NULL;
829 		zfsvfs_free(zfsvfs);
830 		return (error);
831 	}
832 
833 	zfsvfs->z_drain_task = TASKQID_INVALID;
834 	zfsvfs->z_draining = B_FALSE;
835 	zfsvfs->z_drain_cancel = B_TRUE;
836 
837 	*zfvp = zfsvfs;
838 	return (0);
839 }
840 
841 static int
842 zfsvfs_setup(zfsvfs_t *zfsvfs, boolean_t mounting)
843 {
844 	int error;
845 	boolean_t readonly = zfs_is_readonly(zfsvfs);
846 
847 	error = zfs_register_callbacks(zfsvfs->z_vfs);
848 	if (error)
849 		return (error);
850 
851 	/*
852 	 * If we are not mounting (ie: online recv), then we don't
853 	 * have to worry about replaying the log as we blocked all
854 	 * operations out since we closed the ZIL.
855 	 */
856 	if (mounting) {
857 		ASSERT3P(zfsvfs->z_kstat.dk_kstats, ==, NULL);
858 		error = dataset_kstats_create(&zfsvfs->z_kstat, zfsvfs->z_os);
859 		if (error)
860 			return (error);
861 		zfsvfs->z_log = zil_open(zfsvfs->z_os, zfs_get_data,
862 		    &zfsvfs->z_kstat.dk_zil_sums);
863 
864 		/*
865 		 * During replay we remove the read only flag to
866 		 * allow replays to succeed.
867 		 */
868 		if (readonly != 0) {
869 			readonly_changed_cb(zfsvfs, B_FALSE);
870 		} else {
871 			zap_stats_t zs;
872 			if (zap_get_stats(zfsvfs->z_os, zfsvfs->z_unlinkedobj,
873 			    &zs) == 0) {
874 				dataset_kstats_update_nunlinks_kstat(
875 				    &zfsvfs->z_kstat, zs.zs_num_entries);
876 				dprintf_ds(zfsvfs->z_os->os_dsl_dataset,
877 				    "num_entries in unlinked set: %llu",
878 				    zs.zs_num_entries);
879 			}
880 			zfs_unlinked_drain(zfsvfs);
881 			dsl_dir_t *dd = zfsvfs->z_os->os_dsl_dataset->ds_dir;
882 			dd->dd_activity_cancelled = B_FALSE;
883 		}
884 
885 		/*
886 		 * Parse and replay the intent log.
887 		 *
888 		 * Because of ziltest, this must be done after
889 		 * zfs_unlinked_drain().  (Further note: ziltest
890 		 * doesn't use readonly mounts, where
891 		 * zfs_unlinked_drain() isn't called.)  This is because
892 		 * ziltest causes spa_sync() to think it's committed,
893 		 * but actually it is not, so the intent log contains
894 		 * many txg's worth of changes.
895 		 *
896 		 * In particular, if object N is in the unlinked set in
897 		 * the last txg to actually sync, then it could be
898 		 * actually freed in a later txg and then reallocated
899 		 * in a yet later txg.  This would write a "create
900 		 * object N" record to the intent log.  Normally, this
901 		 * would be fine because the spa_sync() would have
902 		 * written out the fact that object N is free, before
903 		 * we could write the "create object N" intent log
904 		 * record.
905 		 *
906 		 * But when we are in ziltest mode, we advance the "open
907 		 * txg" without actually spa_sync()-ing the changes to
908 		 * disk.  So we would see that object N is still
909 		 * allocated and in the unlinked set, and there is an
910 		 * intent log record saying to allocate it.
911 		 */
912 		if (spa_writeable(dmu_objset_spa(zfsvfs->z_os))) {
913 			if (zil_replay_disable) {
914 				zil_destroy(zfsvfs->z_log, B_FALSE);
915 			} else {
916 				zfsvfs->z_replay = B_TRUE;
917 				zil_replay(zfsvfs->z_os, zfsvfs,
918 				    zfs_replay_vector);
919 				zfsvfs->z_replay = B_FALSE;
920 			}
921 		}
922 
923 		/* restore readonly bit */
924 		if (readonly != 0)
925 			readonly_changed_cb(zfsvfs, B_TRUE);
926 	} else {
927 		ASSERT3P(zfsvfs->z_kstat.dk_kstats, !=, NULL);
928 		zfsvfs->z_log = zil_open(zfsvfs->z_os, zfs_get_data,
929 		    &zfsvfs->z_kstat.dk_zil_sums);
930 	}
931 
932 	/*
933 	 * Set the objset user_ptr to track its zfsvfs.
934 	 */
935 	mutex_enter(&zfsvfs->z_os->os_user_ptr_lock);
936 	dmu_objset_set_user(zfsvfs->z_os, zfsvfs);
937 	mutex_exit(&zfsvfs->z_os->os_user_ptr_lock);
938 
939 	return (0);
940 }
941 
942 void
943 zfsvfs_free(zfsvfs_t *zfsvfs)
944 {
945 	int i, size = zfsvfs->z_hold_size;
946 
947 	zfs_fuid_destroy(zfsvfs);
948 
949 	mutex_destroy(&zfsvfs->z_znodes_lock);
950 	mutex_destroy(&zfsvfs->z_lock);
951 	list_destroy(&zfsvfs->z_all_znodes);
952 	ZFS_TEARDOWN_DESTROY(zfsvfs);
953 	rw_destroy(&zfsvfs->z_teardown_inactive_lock);
954 	rw_destroy(&zfsvfs->z_fuid_lock);
955 	for (i = 0; i != size; i++) {
956 		avl_destroy(&zfsvfs->z_hold_trees[i]);
957 		mutex_destroy(&zfsvfs->z_hold_locks[i]);
958 	}
959 	vmem_free(zfsvfs->z_hold_trees, sizeof (avl_tree_t) * size);
960 	vmem_free(zfsvfs->z_hold_locks, sizeof (kmutex_t) * size);
961 	zfsvfs_vfs_free(zfsvfs->z_vfs);
962 	dataset_kstats_destroy(&zfsvfs->z_kstat);
963 	kmem_free(zfsvfs, sizeof (zfsvfs_t));
964 }
965 
966 static void
967 zfs_set_fuid_feature(zfsvfs_t *zfsvfs)
968 {
969 	zfsvfs->z_use_fuids = USE_FUIDS(zfsvfs->z_version, zfsvfs->z_os);
970 	zfsvfs->z_use_sa = USE_SA(zfsvfs->z_version, zfsvfs->z_os);
971 }
972 
973 static void
974 zfs_unregister_callbacks(zfsvfs_t *zfsvfs)
975 {
976 	objset_t *os = zfsvfs->z_os;
977 
978 	if (!dmu_objset_is_snapshot(os))
979 		dsl_prop_unregister_all(dmu_objset_ds(os), zfsvfs);
980 }
981 
982 #ifdef HAVE_MLSLABEL
983 /*
984  * Check that the hex label string is appropriate for the dataset being
985  * mounted into the global_zone proper.
986  *
987  * Return an error if the hex label string is not default or
988  * admin_low/admin_high.  For admin_low labels, the corresponding
989  * dataset must be readonly.
990  */
991 int
992 zfs_check_global_label(const char *dsname, const char *hexsl)
993 {
994 	if (strcasecmp(hexsl, ZFS_MLSLABEL_DEFAULT) == 0)
995 		return (0);
996 	if (strcasecmp(hexsl, ADMIN_HIGH) == 0)
997 		return (0);
998 	if (strcasecmp(hexsl, ADMIN_LOW) == 0) {
999 		/* must be readonly */
1000 		uint64_t rdonly;
1001 
1002 		if (dsl_prop_get_integer(dsname,
1003 		    zfs_prop_to_name(ZFS_PROP_READONLY), &rdonly, NULL))
1004 			return (SET_ERROR(EACCES));
1005 		return (rdonly ? 0 : SET_ERROR(EACCES));
1006 	}
1007 	return (SET_ERROR(EACCES));
1008 }
1009 #endif /* HAVE_MLSLABEL */
1010 
1011 static int
1012 zfs_statfs_project(zfsvfs_t *zfsvfs, znode_t *zp, struct kstatfs *statp,
1013     uint32_t bshift)
1014 {
1015 	char buf[20 + DMU_OBJACCT_PREFIX_LEN];
1016 	uint64_t offset = DMU_OBJACCT_PREFIX_LEN;
1017 	uint64_t quota;
1018 	uint64_t used;
1019 	int err;
1020 
1021 	strlcpy(buf, DMU_OBJACCT_PREFIX, DMU_OBJACCT_PREFIX_LEN + 1);
1022 	err = zfs_id_to_fuidstr(zfsvfs, NULL, zp->z_projid, buf + offset,
1023 	    sizeof (buf) - offset, B_FALSE);
1024 	if (err)
1025 		return (err);
1026 
1027 	if (zfsvfs->z_projectquota_obj == 0)
1028 		goto objs;
1029 
1030 	err = zap_lookup(zfsvfs->z_os, zfsvfs->z_projectquota_obj,
1031 	    buf + offset, 8, 1, &quota);
1032 	if (err == ENOENT)
1033 		goto objs;
1034 	else if (err)
1035 		return (err);
1036 
1037 	err = zap_lookup(zfsvfs->z_os, DMU_PROJECTUSED_OBJECT,
1038 	    buf + offset, 8, 1, &used);
1039 	if (unlikely(err == ENOENT)) {
1040 		uint32_t blksize;
1041 		u_longlong_t nblocks;
1042 
1043 		/*
1044 		 * Quota accounting is async, so it is possible race case.
1045 		 * There is at least one object with the given project ID.
1046 		 */
1047 		sa_object_size(zp->z_sa_hdl, &blksize, &nblocks);
1048 		if (unlikely(zp->z_blksz == 0))
1049 			blksize = zfsvfs->z_max_blksz;
1050 
1051 		used = blksize * nblocks;
1052 	} else if (err) {
1053 		return (err);
1054 	}
1055 
1056 	statp->f_blocks = quota >> bshift;
1057 	statp->f_bfree = (quota > used) ? ((quota - used) >> bshift) : 0;
1058 	statp->f_bavail = statp->f_bfree;
1059 
1060 objs:
1061 	if (zfsvfs->z_projectobjquota_obj == 0)
1062 		return (0);
1063 
1064 	err = zap_lookup(zfsvfs->z_os, zfsvfs->z_projectobjquota_obj,
1065 	    buf + offset, 8, 1, &quota);
1066 	if (err == ENOENT)
1067 		return (0);
1068 	else if (err)
1069 		return (err);
1070 
1071 	err = zap_lookup(zfsvfs->z_os, DMU_PROJECTUSED_OBJECT,
1072 	    buf, 8, 1, &used);
1073 	if (unlikely(err == ENOENT)) {
1074 		/*
1075 		 * Quota accounting is async, so it is possible race case.
1076 		 * There is at least one object with the given project ID.
1077 		 */
1078 		used = 1;
1079 	} else if (err) {
1080 		return (err);
1081 	}
1082 
1083 	statp->f_files = quota;
1084 	statp->f_ffree = (quota > used) ? (quota - used) : 0;
1085 
1086 	return (0);
1087 }
1088 
1089 int
1090 zfs_statvfs(struct inode *ip, struct kstatfs *statp)
1091 {
1092 	zfsvfs_t *zfsvfs = ITOZSB(ip);
1093 	uint64_t refdbytes, availbytes, usedobjs, availobjs;
1094 	int err = 0;
1095 
1096 	if ((err = zfs_enter(zfsvfs, FTAG)) != 0)
1097 		return (err);
1098 
1099 	dmu_objset_space(zfsvfs->z_os,
1100 	    &refdbytes, &availbytes, &usedobjs, &availobjs);
1101 
1102 	uint64_t fsid = dmu_objset_fsid_guid(zfsvfs->z_os);
1103 	/*
1104 	 * The underlying storage pool actually uses multiple block
1105 	 * size.  Under Solaris frsize (fragment size) is reported as
1106 	 * the smallest block size we support, and bsize (block size)
1107 	 * as the filesystem's maximum block size.  Unfortunately,
1108 	 * under Linux the fragment size and block size are often used
1109 	 * interchangeably.  Thus we are forced to report both of them
1110 	 * as the filesystem's maximum block size.
1111 	 */
1112 	statp->f_frsize = zfsvfs->z_max_blksz;
1113 	statp->f_bsize = zfsvfs->z_max_blksz;
1114 	uint32_t bshift = fls(statp->f_bsize) - 1;
1115 
1116 	/*
1117 	 * The following report "total" blocks of various kinds in
1118 	 * the file system, but reported in terms of f_bsize - the
1119 	 * "preferred" size.
1120 	 */
1121 
1122 	/* Round up so we never have a filesystem using 0 blocks. */
1123 	refdbytes = P2ROUNDUP(refdbytes, statp->f_bsize);
1124 	statp->f_blocks = (refdbytes + availbytes) >> bshift;
1125 	statp->f_bfree = availbytes >> bshift;
1126 	statp->f_bavail = statp->f_bfree; /* no root reservation */
1127 
1128 	/*
1129 	 * statvfs() should really be called statufs(), because it assumes
1130 	 * static metadata.  ZFS doesn't preallocate files, so the best
1131 	 * we can do is report the max that could possibly fit in f_files,
1132 	 * and that minus the number actually used in f_ffree.
1133 	 * For f_ffree, report the smaller of the number of objects available
1134 	 * and the number of blocks (each object will take at least a block).
1135 	 */
1136 	statp->f_ffree = MIN(availobjs, availbytes >> DNODE_SHIFT);
1137 	statp->f_files = statp->f_ffree + usedobjs;
1138 	statp->f_fsid.val[0] = (uint32_t)fsid;
1139 	statp->f_fsid.val[1] = (uint32_t)(fsid >> 32);
1140 	statp->f_type = ZFS_SUPER_MAGIC;
1141 	statp->f_namelen = MAXNAMELEN - 1;
1142 
1143 	/*
1144 	 * We have all of 40 characters to stuff a string here.
1145 	 * Is there anything useful we could/should provide?
1146 	 */
1147 	memset(statp->f_spare, 0, sizeof (statp->f_spare));
1148 
1149 	if (dmu_objset_projectquota_enabled(zfsvfs->z_os) &&
1150 	    dmu_objset_projectquota_present(zfsvfs->z_os)) {
1151 		znode_t *zp = ITOZ(ip);
1152 
1153 		if (zp->z_pflags & ZFS_PROJINHERIT && zp->z_projid &&
1154 		    zpl_is_valid_projid(zp->z_projid))
1155 			err = zfs_statfs_project(zfsvfs, zp, statp, bshift);
1156 	}
1157 
1158 	zfs_exit(zfsvfs, FTAG);
1159 	return (err);
1160 }
1161 
1162 static int
1163 zfs_root(zfsvfs_t *zfsvfs, struct inode **ipp)
1164 {
1165 	znode_t *rootzp;
1166 	int error;
1167 
1168 	if ((error = zfs_enter(zfsvfs, FTAG)) != 0)
1169 		return (error);
1170 
1171 	error = zfs_zget(zfsvfs, zfsvfs->z_root, &rootzp);
1172 	if (error == 0)
1173 		*ipp = ZTOI(rootzp);
1174 
1175 	zfs_exit(zfsvfs, FTAG);
1176 	return (error);
1177 }
1178 
1179 /*
1180  * Linux kernels older than 3.1 do not support a per-filesystem shrinker.
1181  * To accommodate this we must improvise and manually walk the list of znodes
1182  * attempting to prune dentries in order to be able to drop the inodes.
1183  *
1184  * To avoid scanning the same znodes multiple times they are always rotated
1185  * to the end of the z_all_znodes list.  New znodes are inserted at the
1186  * end of the list so we're always scanning the oldest znodes first.
1187  */
1188 static int
1189 zfs_prune_aliases(zfsvfs_t *zfsvfs, unsigned long nr_to_scan)
1190 {
1191 	znode_t **zp_array, *zp;
1192 	int max_array = MIN(nr_to_scan, PAGE_SIZE * 8 / sizeof (znode_t *));
1193 	int objects = 0;
1194 	int i = 0, j = 0;
1195 
1196 	zp_array = kmem_zalloc(max_array * sizeof (znode_t *), KM_SLEEP);
1197 
1198 	mutex_enter(&zfsvfs->z_znodes_lock);
1199 	while ((zp = list_head(&zfsvfs->z_all_znodes)) != NULL) {
1200 
1201 		if ((i++ > nr_to_scan) || (j >= max_array))
1202 			break;
1203 
1204 		ASSERT(list_link_active(&zp->z_link_node));
1205 		list_remove(&zfsvfs->z_all_znodes, zp);
1206 		list_insert_tail(&zfsvfs->z_all_znodes, zp);
1207 
1208 		/* Skip active znodes and .zfs entries */
1209 		if (MUTEX_HELD(&zp->z_lock) || zp->z_is_ctldir)
1210 			continue;
1211 
1212 		if (igrab(ZTOI(zp)) == NULL)
1213 			continue;
1214 
1215 		zp_array[j] = zp;
1216 		j++;
1217 	}
1218 	mutex_exit(&zfsvfs->z_znodes_lock);
1219 
1220 	for (i = 0; i < j; i++) {
1221 		zp = zp_array[i];
1222 
1223 		ASSERT3P(zp, !=, NULL);
1224 		d_prune_aliases(ZTOI(zp));
1225 
1226 		if (atomic_read(&ZTOI(zp)->i_count) == 1)
1227 			objects++;
1228 
1229 		zrele(zp);
1230 	}
1231 
1232 	kmem_free(zp_array, max_array * sizeof (znode_t *));
1233 
1234 	return (objects);
1235 }
1236 
1237 /*
1238  * The ARC has requested that the filesystem drop entries from the dentry
1239  * and inode caches.  This can occur when the ARC needs to free meta data
1240  * blocks but can't because they are all pinned by entries in these caches.
1241  */
1242 int
1243 zfs_prune(struct super_block *sb, unsigned long nr_to_scan, int *objects)
1244 {
1245 	zfsvfs_t *zfsvfs = sb->s_fs_info;
1246 	int error = 0;
1247 	struct shrinker *shrinker = &sb->s_shrink;
1248 	struct shrink_control sc = {
1249 		.nr_to_scan = nr_to_scan,
1250 		.gfp_mask = GFP_KERNEL,
1251 	};
1252 
1253 	if ((error = zfs_enter(zfsvfs, FTAG)) != 0)
1254 		return (error);
1255 
1256 #if defined(HAVE_SPLIT_SHRINKER_CALLBACK) && \
1257 	defined(SHRINK_CONTROL_HAS_NID) && \
1258 	defined(SHRINKER_NUMA_AWARE)
1259 	if (sb->s_shrink.flags & SHRINKER_NUMA_AWARE) {
1260 		*objects = 0;
1261 		for_each_online_node(sc.nid) {
1262 			*objects += (*shrinker->scan_objects)(shrinker, &sc);
1263 			/*
1264 			 * reset sc.nr_to_scan, modified by
1265 			 * scan_objects == super_cache_scan
1266 			 */
1267 			sc.nr_to_scan = nr_to_scan;
1268 		}
1269 	} else {
1270 			*objects = (*shrinker->scan_objects)(shrinker, &sc);
1271 	}
1272 
1273 #elif defined(HAVE_SPLIT_SHRINKER_CALLBACK)
1274 	*objects = (*shrinker->scan_objects)(shrinker, &sc);
1275 #elif defined(HAVE_SINGLE_SHRINKER_CALLBACK)
1276 	*objects = (*shrinker->shrink)(shrinker, &sc);
1277 #elif defined(HAVE_D_PRUNE_ALIASES)
1278 #define	D_PRUNE_ALIASES_IS_DEFAULT
1279 	*objects = zfs_prune_aliases(zfsvfs, nr_to_scan);
1280 #else
1281 #error "No available dentry and inode cache pruning mechanism."
1282 #endif
1283 
1284 #if defined(HAVE_D_PRUNE_ALIASES) && !defined(D_PRUNE_ALIASES_IS_DEFAULT)
1285 #undef	D_PRUNE_ALIASES_IS_DEFAULT
1286 	/*
1287 	 * Fall back to zfs_prune_aliases if the kernel's per-superblock
1288 	 * shrinker couldn't free anything, possibly due to the inodes being
1289 	 * allocated in a different memcg.
1290 	 */
1291 	if (*objects == 0)
1292 		*objects = zfs_prune_aliases(zfsvfs, nr_to_scan);
1293 #endif
1294 
1295 	zfs_exit(zfsvfs, FTAG);
1296 
1297 	dprintf_ds(zfsvfs->z_os->os_dsl_dataset,
1298 	    "pruning, nr_to_scan=%lu objects=%d error=%d\n",
1299 	    nr_to_scan, *objects, error);
1300 
1301 	return (error);
1302 }
1303 
1304 /*
1305  * Teardown the zfsvfs_t.
1306  *
1307  * Note, if 'unmounting' is FALSE, we return with the 'z_teardown_lock'
1308  * and 'z_teardown_inactive_lock' held.
1309  */
1310 static int
1311 zfsvfs_teardown(zfsvfs_t *zfsvfs, boolean_t unmounting)
1312 {
1313 	znode_t	*zp;
1314 
1315 	zfs_unlinked_drain_stop_wait(zfsvfs);
1316 
1317 	/*
1318 	 * If someone has not already unmounted this file system,
1319 	 * drain the zrele_taskq to ensure all active references to the
1320 	 * zfsvfs_t have been handled only then can it be safely destroyed.
1321 	 */
1322 	if (zfsvfs->z_os) {
1323 		/*
1324 		 * If we're unmounting we have to wait for the list to
1325 		 * drain completely.
1326 		 *
1327 		 * If we're not unmounting there's no guarantee the list
1328 		 * will drain completely, but iputs run from the taskq
1329 		 * may add the parents of dir-based xattrs to the taskq
1330 		 * so we want to wait for these.
1331 		 *
1332 		 * We can safely read z_nr_znodes without locking because the
1333 		 * VFS has already blocked operations which add to the
1334 		 * z_all_znodes list and thus increment z_nr_znodes.
1335 		 */
1336 		int round = 0;
1337 		while (zfsvfs->z_nr_znodes > 0) {
1338 			taskq_wait_outstanding(dsl_pool_zrele_taskq(
1339 			    dmu_objset_pool(zfsvfs->z_os)), 0);
1340 			if (++round > 1 && !unmounting)
1341 				break;
1342 		}
1343 	}
1344 
1345 	ZFS_TEARDOWN_ENTER_WRITE(zfsvfs, FTAG);
1346 
1347 	if (!unmounting) {
1348 		/*
1349 		 * We purge the parent filesystem's super block as the
1350 		 * parent filesystem and all of its snapshots have their
1351 		 * inode's super block set to the parent's filesystem's
1352 		 * super block.  Note,  'z_parent' is self referential
1353 		 * for non-snapshots.
1354 		 */
1355 		shrink_dcache_sb(zfsvfs->z_parent->z_sb);
1356 	}
1357 
1358 	/*
1359 	 * Close the zil. NB: Can't close the zil while zfs_inactive
1360 	 * threads are blocked as zil_close can call zfs_inactive.
1361 	 */
1362 	if (zfsvfs->z_log) {
1363 		zil_close(zfsvfs->z_log);
1364 		zfsvfs->z_log = NULL;
1365 	}
1366 
1367 	rw_enter(&zfsvfs->z_teardown_inactive_lock, RW_WRITER);
1368 
1369 	/*
1370 	 * If we are not unmounting (ie: online recv) and someone already
1371 	 * unmounted this file system while we were doing the switcheroo,
1372 	 * or a reopen of z_os failed then just bail out now.
1373 	 */
1374 	if (!unmounting && (zfsvfs->z_unmounted || zfsvfs->z_os == NULL)) {
1375 		rw_exit(&zfsvfs->z_teardown_inactive_lock);
1376 		ZFS_TEARDOWN_EXIT(zfsvfs, FTAG);
1377 		return (SET_ERROR(EIO));
1378 	}
1379 
1380 	/*
1381 	 * At this point there are no VFS ops active, and any new VFS ops
1382 	 * will fail with EIO since we have z_teardown_lock for writer (only
1383 	 * relevant for forced unmount).
1384 	 *
1385 	 * Release all holds on dbufs. We also grab an extra reference to all
1386 	 * the remaining inodes so that the kernel does not attempt to free
1387 	 * any inodes of a suspended fs. This can cause deadlocks since the
1388 	 * zfs_resume_fs() process may involve starting threads, which might
1389 	 * attempt to free unreferenced inodes to free up memory for the new
1390 	 * thread.
1391 	 */
1392 	if (!unmounting) {
1393 		mutex_enter(&zfsvfs->z_znodes_lock);
1394 		for (zp = list_head(&zfsvfs->z_all_znodes); zp != NULL;
1395 		    zp = list_next(&zfsvfs->z_all_znodes, zp)) {
1396 			if (zp->z_sa_hdl)
1397 				zfs_znode_dmu_fini(zp);
1398 			if (igrab(ZTOI(zp)) != NULL)
1399 				zp->z_suspended = B_TRUE;
1400 
1401 		}
1402 		mutex_exit(&zfsvfs->z_znodes_lock);
1403 	}
1404 
1405 	/*
1406 	 * If we are unmounting, set the unmounted flag and let new VFS ops
1407 	 * unblock.  zfs_inactive will have the unmounted behavior, and all
1408 	 * other VFS ops will fail with EIO.
1409 	 */
1410 	if (unmounting) {
1411 		zfsvfs->z_unmounted = B_TRUE;
1412 		rw_exit(&zfsvfs->z_teardown_inactive_lock);
1413 		ZFS_TEARDOWN_EXIT(zfsvfs, FTAG);
1414 	}
1415 
1416 	/*
1417 	 * z_os will be NULL if there was an error in attempting to reopen
1418 	 * zfsvfs, so just return as the properties had already been
1419 	 *
1420 	 * unregistered and cached data had been evicted before.
1421 	 */
1422 	if (zfsvfs->z_os == NULL)
1423 		return (0);
1424 
1425 	/*
1426 	 * Unregister properties.
1427 	 */
1428 	zfs_unregister_callbacks(zfsvfs);
1429 
1430 	/*
1431 	 * Evict cached data. We must write out any dirty data before
1432 	 * disowning the dataset.
1433 	 */
1434 	objset_t *os = zfsvfs->z_os;
1435 	boolean_t os_dirty = B_FALSE;
1436 	for (int t = 0; t < TXG_SIZE; t++) {
1437 		if (dmu_objset_is_dirty(os, t)) {
1438 			os_dirty = B_TRUE;
1439 			break;
1440 		}
1441 	}
1442 	if (!zfs_is_readonly(zfsvfs) && os_dirty) {
1443 		txg_wait_synced(dmu_objset_pool(zfsvfs->z_os), 0);
1444 	}
1445 	dmu_objset_evict_dbufs(zfsvfs->z_os);
1446 	dsl_dir_t *dd = os->os_dsl_dataset->ds_dir;
1447 	dsl_dir_cancel_waiters(dd);
1448 
1449 	return (0);
1450 }
1451 
1452 #if defined(HAVE_SUPER_SETUP_BDI_NAME)
1453 atomic_long_t zfs_bdi_seq = ATOMIC_LONG_INIT(0);
1454 #endif
1455 
1456 int
1457 zfs_domount(struct super_block *sb, zfs_mnt_t *zm, int silent)
1458 {
1459 	const char *osname = zm->mnt_osname;
1460 	struct inode *root_inode = NULL;
1461 	uint64_t recordsize;
1462 	int error = 0;
1463 	zfsvfs_t *zfsvfs = NULL;
1464 	vfs_t *vfs = NULL;
1465 	int canwrite;
1466 	int dataset_visible_zone;
1467 
1468 	ASSERT(zm);
1469 	ASSERT(osname);
1470 
1471 	dataset_visible_zone = zone_dataset_visible(osname, &canwrite);
1472 
1473 	/*
1474 	 * Refuse to mount a filesystem if we are in a namespace and the
1475 	 * dataset is not visible or writable in that namespace.
1476 	 */
1477 	if (!INGLOBALZONE(curproc) &&
1478 	    (!dataset_visible_zone || !canwrite)) {
1479 		return (SET_ERROR(EPERM));
1480 	}
1481 
1482 	error = zfsvfs_parse_options(zm->mnt_data, &vfs);
1483 	if (error)
1484 		return (error);
1485 
1486 	/*
1487 	 * If a non-writable filesystem is being mounted without the
1488 	 * read-only flag, pretend it was set, as done for snapshots.
1489 	 */
1490 	if (!canwrite)
1491 		vfs->vfs_readonly = true;
1492 
1493 	error = zfsvfs_create(osname, vfs->vfs_readonly, &zfsvfs);
1494 	if (error) {
1495 		zfsvfs_vfs_free(vfs);
1496 		goto out;
1497 	}
1498 
1499 	if ((error = dsl_prop_get_integer(osname, "recordsize",
1500 	    &recordsize, NULL))) {
1501 		zfsvfs_vfs_free(vfs);
1502 		goto out;
1503 	}
1504 
1505 	vfs->vfs_data = zfsvfs;
1506 	zfsvfs->z_vfs = vfs;
1507 	zfsvfs->z_sb = sb;
1508 	sb->s_fs_info = zfsvfs;
1509 	sb->s_magic = ZFS_SUPER_MAGIC;
1510 	sb->s_maxbytes = MAX_LFS_FILESIZE;
1511 	sb->s_time_gran = 1;
1512 	sb->s_blocksize = recordsize;
1513 	sb->s_blocksize_bits = ilog2(recordsize);
1514 
1515 	error = -zpl_bdi_setup(sb, "zfs");
1516 	if (error)
1517 		goto out;
1518 
1519 	sb->s_bdi->ra_pages = 0;
1520 
1521 	/* Set callback operations for the file system. */
1522 	sb->s_op = &zpl_super_operations;
1523 	sb->s_xattr = zpl_xattr_handlers;
1524 	sb->s_export_op = &zpl_export_operations;
1525 
1526 	/* Set features for file system. */
1527 	zfs_set_fuid_feature(zfsvfs);
1528 
1529 	if (dmu_objset_is_snapshot(zfsvfs->z_os)) {
1530 		uint64_t pval;
1531 
1532 		atime_changed_cb(zfsvfs, B_FALSE);
1533 		readonly_changed_cb(zfsvfs, B_TRUE);
1534 		if ((error = dsl_prop_get_integer(osname,
1535 		    "xattr", &pval, NULL)))
1536 			goto out;
1537 		xattr_changed_cb(zfsvfs, pval);
1538 		if ((error = dsl_prop_get_integer(osname,
1539 		    "acltype", &pval, NULL)))
1540 			goto out;
1541 		acltype_changed_cb(zfsvfs, pval);
1542 		zfsvfs->z_issnap = B_TRUE;
1543 		zfsvfs->z_os->os_sync = ZFS_SYNC_DISABLED;
1544 		zfsvfs->z_snap_defer_time = jiffies;
1545 
1546 		mutex_enter(&zfsvfs->z_os->os_user_ptr_lock);
1547 		dmu_objset_set_user(zfsvfs->z_os, zfsvfs);
1548 		mutex_exit(&zfsvfs->z_os->os_user_ptr_lock);
1549 	} else {
1550 		if ((error = zfsvfs_setup(zfsvfs, B_TRUE)))
1551 			goto out;
1552 	}
1553 
1554 	/* Allocate a root inode for the filesystem. */
1555 	error = zfs_root(zfsvfs, &root_inode);
1556 	if (error) {
1557 		(void) zfs_umount(sb);
1558 		zfsvfs = NULL; /* avoid double-free; first in zfs_umount */
1559 		goto out;
1560 	}
1561 
1562 	/* Allocate a root dentry for the filesystem */
1563 	sb->s_root = d_make_root(root_inode);
1564 	if (sb->s_root == NULL) {
1565 		(void) zfs_umount(sb);
1566 		zfsvfs = NULL; /* avoid double-free; first in zfs_umount */
1567 		error = SET_ERROR(ENOMEM);
1568 		goto out;
1569 	}
1570 
1571 	if (!zfsvfs->z_issnap)
1572 		zfsctl_create(zfsvfs);
1573 
1574 	zfsvfs->z_arc_prune = arc_add_prune_callback(zpl_prune_sb, sb);
1575 out:
1576 	if (error) {
1577 		if (zfsvfs != NULL) {
1578 			dmu_objset_disown(zfsvfs->z_os, B_TRUE, zfsvfs);
1579 			zfsvfs_free(zfsvfs);
1580 		}
1581 		/*
1582 		 * make sure we don't have dangling sb->s_fs_info which
1583 		 * zfs_preumount will use.
1584 		 */
1585 		sb->s_fs_info = NULL;
1586 	}
1587 
1588 	return (error);
1589 }
1590 
1591 /*
1592  * Called when an unmount is requested and certain sanity checks have
1593  * already passed.  At this point no dentries or inodes have been reclaimed
1594  * from their respective caches.  We drop the extra reference on the .zfs
1595  * control directory to allow everything to be reclaimed.  All snapshots
1596  * must already have been unmounted to reach this point.
1597  */
1598 void
1599 zfs_preumount(struct super_block *sb)
1600 {
1601 	zfsvfs_t *zfsvfs = sb->s_fs_info;
1602 
1603 	/* zfsvfs is NULL when zfs_domount fails during mount */
1604 	if (zfsvfs) {
1605 		zfs_unlinked_drain_stop_wait(zfsvfs);
1606 		zfsctl_destroy(sb->s_fs_info);
1607 		/*
1608 		 * Wait for zrele_async before entering evict_inodes in
1609 		 * generic_shutdown_super. The reason we must finish before
1610 		 * evict_inodes is when lazytime is on, or when zfs_purgedir
1611 		 * calls zfs_zget, zrele would bump i_count from 0 to 1. This
1612 		 * would race with the i_count check in evict_inodes. This means
1613 		 * it could destroy the inode while we are still using it.
1614 		 *
1615 		 * We wait for two passes. xattr directories in the first pass
1616 		 * may add xattr entries in zfs_purgedir, so in the second pass
1617 		 * we wait for them. We don't use taskq_wait here because it is
1618 		 * a pool wide taskq. Other mounted filesystems can constantly
1619 		 * do zrele_async and there's no guarantee when taskq will be
1620 		 * empty.
1621 		 */
1622 		taskq_wait_outstanding(dsl_pool_zrele_taskq(
1623 		    dmu_objset_pool(zfsvfs->z_os)), 0);
1624 		taskq_wait_outstanding(dsl_pool_zrele_taskq(
1625 		    dmu_objset_pool(zfsvfs->z_os)), 0);
1626 	}
1627 }
1628 
1629 /*
1630  * Called once all other unmount released tear down has occurred.
1631  * It is our responsibility to release any remaining infrastructure.
1632  */
1633 int
1634 zfs_umount(struct super_block *sb)
1635 {
1636 	zfsvfs_t *zfsvfs = sb->s_fs_info;
1637 	objset_t *os;
1638 
1639 	if (zfsvfs->z_arc_prune != NULL)
1640 		arc_remove_prune_callback(zfsvfs->z_arc_prune);
1641 	VERIFY(zfsvfs_teardown(zfsvfs, B_TRUE) == 0);
1642 	os = zfsvfs->z_os;
1643 	zpl_bdi_destroy(sb);
1644 
1645 	/*
1646 	 * z_os will be NULL if there was an error in
1647 	 * attempting to reopen zfsvfs.
1648 	 */
1649 	if (os != NULL) {
1650 		/*
1651 		 * Unset the objset user_ptr.
1652 		 */
1653 		mutex_enter(&os->os_user_ptr_lock);
1654 		dmu_objset_set_user(os, NULL);
1655 		mutex_exit(&os->os_user_ptr_lock);
1656 
1657 		/*
1658 		 * Finally release the objset
1659 		 */
1660 		dmu_objset_disown(os, B_TRUE, zfsvfs);
1661 	}
1662 
1663 	zfsvfs_free(zfsvfs);
1664 	return (0);
1665 }
1666 
1667 int
1668 zfs_remount(struct super_block *sb, int *flags, zfs_mnt_t *zm)
1669 {
1670 	zfsvfs_t *zfsvfs = sb->s_fs_info;
1671 	vfs_t *vfsp;
1672 	boolean_t issnap = dmu_objset_is_snapshot(zfsvfs->z_os);
1673 	int error;
1674 
1675 	if ((issnap || !spa_writeable(dmu_objset_spa(zfsvfs->z_os))) &&
1676 	    !(*flags & SB_RDONLY)) {
1677 		*flags |= SB_RDONLY;
1678 		return (EROFS);
1679 	}
1680 
1681 	error = zfsvfs_parse_options(zm->mnt_data, &vfsp);
1682 	if (error)
1683 		return (error);
1684 
1685 	if (!zfs_is_readonly(zfsvfs) && (*flags & SB_RDONLY))
1686 		txg_wait_synced(dmu_objset_pool(zfsvfs->z_os), 0);
1687 
1688 	zfs_unregister_callbacks(zfsvfs);
1689 	zfsvfs_vfs_free(zfsvfs->z_vfs);
1690 
1691 	vfsp->vfs_data = zfsvfs;
1692 	zfsvfs->z_vfs = vfsp;
1693 	if (!issnap)
1694 		(void) zfs_register_callbacks(vfsp);
1695 
1696 	return (error);
1697 }
1698 
1699 int
1700 zfs_vget(struct super_block *sb, struct inode **ipp, fid_t *fidp)
1701 {
1702 	zfsvfs_t	*zfsvfs = sb->s_fs_info;
1703 	znode_t		*zp;
1704 	uint64_t	object = 0;
1705 	uint64_t	fid_gen = 0;
1706 	uint64_t	gen_mask;
1707 	uint64_t	zp_gen;
1708 	int		i, err;
1709 
1710 	*ipp = NULL;
1711 
1712 	if (fidp->fid_len == SHORT_FID_LEN || fidp->fid_len == LONG_FID_LEN) {
1713 		zfid_short_t	*zfid = (zfid_short_t *)fidp;
1714 
1715 		for (i = 0; i < sizeof (zfid->zf_object); i++)
1716 			object |= ((uint64_t)zfid->zf_object[i]) << (8 * i);
1717 
1718 		for (i = 0; i < sizeof (zfid->zf_gen); i++)
1719 			fid_gen |= ((uint64_t)zfid->zf_gen[i]) << (8 * i);
1720 	} else {
1721 		return (SET_ERROR(EINVAL));
1722 	}
1723 
1724 	/* LONG_FID_LEN means snapdirs */
1725 	if (fidp->fid_len == LONG_FID_LEN) {
1726 		zfid_long_t	*zlfid = (zfid_long_t *)fidp;
1727 		uint64_t	objsetid = 0;
1728 		uint64_t	setgen = 0;
1729 
1730 		for (i = 0; i < sizeof (zlfid->zf_setid); i++)
1731 			objsetid |= ((uint64_t)zlfid->zf_setid[i]) << (8 * i);
1732 
1733 		for (i = 0; i < sizeof (zlfid->zf_setgen); i++)
1734 			setgen |= ((uint64_t)zlfid->zf_setgen[i]) << (8 * i);
1735 
1736 		if (objsetid != ZFSCTL_INO_SNAPDIRS - object) {
1737 			dprintf("snapdir fid: objsetid (%llu) != "
1738 			    "ZFSCTL_INO_SNAPDIRS (%llu) - object (%llu)\n",
1739 			    objsetid, ZFSCTL_INO_SNAPDIRS, object);
1740 
1741 			return (SET_ERROR(EINVAL));
1742 		}
1743 
1744 		if (fid_gen > 1 || setgen != 0) {
1745 			dprintf("snapdir fid: fid_gen (%llu) and setgen "
1746 			    "(%llu)\n", fid_gen, setgen);
1747 			return (SET_ERROR(EINVAL));
1748 		}
1749 
1750 		return (zfsctl_snapdir_vget(sb, objsetid, fid_gen, ipp));
1751 	}
1752 
1753 	if ((err = zfs_enter(zfsvfs, FTAG)) != 0)
1754 		return (err);
1755 	/* A zero fid_gen means we are in the .zfs control directories */
1756 	if (fid_gen == 0 &&
1757 	    (object == ZFSCTL_INO_ROOT || object == ZFSCTL_INO_SNAPDIR)) {
1758 		*ipp = zfsvfs->z_ctldir;
1759 		ASSERT(*ipp != NULL);
1760 		if (object == ZFSCTL_INO_SNAPDIR) {
1761 			VERIFY(zfsctl_root_lookup(*ipp, "snapshot", ipp,
1762 			    0, kcred, NULL, NULL) == 0);
1763 		} else {
1764 			/*
1765 			 * Must have an existing ref, so igrab()
1766 			 * cannot return NULL
1767 			 */
1768 			VERIFY3P(igrab(*ipp), !=, NULL);
1769 		}
1770 		zfs_exit(zfsvfs, FTAG);
1771 		return (0);
1772 	}
1773 
1774 	gen_mask = -1ULL >> (64 - 8 * i);
1775 
1776 	dprintf("getting %llu [%llu mask %llx]\n", object, fid_gen, gen_mask);
1777 	if ((err = zfs_zget(zfsvfs, object, &zp))) {
1778 		zfs_exit(zfsvfs, FTAG);
1779 		return (err);
1780 	}
1781 
1782 	/* Don't export xattr stuff */
1783 	if (zp->z_pflags & ZFS_XATTR) {
1784 		zrele(zp);
1785 		zfs_exit(zfsvfs, FTAG);
1786 		return (SET_ERROR(ENOENT));
1787 	}
1788 
1789 	(void) sa_lookup(zp->z_sa_hdl, SA_ZPL_GEN(zfsvfs), &zp_gen,
1790 	    sizeof (uint64_t));
1791 	zp_gen = zp_gen & gen_mask;
1792 	if (zp_gen == 0)
1793 		zp_gen = 1;
1794 	if ((fid_gen == 0) && (zfsvfs->z_root == object))
1795 		fid_gen = zp_gen;
1796 	if (zp->z_unlinked || zp_gen != fid_gen) {
1797 		dprintf("znode gen (%llu) != fid gen (%llu)\n", zp_gen,
1798 		    fid_gen);
1799 		zrele(zp);
1800 		zfs_exit(zfsvfs, FTAG);
1801 		return (SET_ERROR(ENOENT));
1802 	}
1803 
1804 	*ipp = ZTOI(zp);
1805 	if (*ipp)
1806 		zfs_znode_update_vfs(ITOZ(*ipp));
1807 
1808 	zfs_exit(zfsvfs, FTAG);
1809 	return (0);
1810 }
1811 
1812 /*
1813  * Block out VFS ops and close zfsvfs_t
1814  *
1815  * Note, if successful, then we return with the 'z_teardown_lock' and
1816  * 'z_teardown_inactive_lock' write held.  We leave ownership of the underlying
1817  * dataset and objset intact so that they can be atomically handed off during
1818  * a subsequent rollback or recv operation and the resume thereafter.
1819  */
1820 int
1821 zfs_suspend_fs(zfsvfs_t *zfsvfs)
1822 {
1823 	int error;
1824 
1825 	if ((error = zfsvfs_teardown(zfsvfs, B_FALSE)) != 0)
1826 		return (error);
1827 
1828 	return (0);
1829 }
1830 
1831 /*
1832  * Rebuild SA and release VOPs.  Note that ownership of the underlying dataset
1833  * is an invariant across any of the operations that can be performed while the
1834  * filesystem was suspended.  Whether it succeeded or failed, the preconditions
1835  * are the same: the relevant objset and associated dataset are owned by
1836  * zfsvfs, held, and long held on entry.
1837  */
1838 int
1839 zfs_resume_fs(zfsvfs_t *zfsvfs, dsl_dataset_t *ds)
1840 {
1841 	int err, err2;
1842 	znode_t *zp;
1843 
1844 	ASSERT(ZFS_TEARDOWN_WRITE_HELD(zfsvfs));
1845 	ASSERT(RW_WRITE_HELD(&zfsvfs->z_teardown_inactive_lock));
1846 
1847 	/*
1848 	 * We already own this, so just update the objset_t, as the one we
1849 	 * had before may have been evicted.
1850 	 */
1851 	objset_t *os;
1852 	VERIFY3P(ds->ds_owner, ==, zfsvfs);
1853 	VERIFY(dsl_dataset_long_held(ds));
1854 	dsl_pool_t *dp = spa_get_dsl(dsl_dataset_get_spa(ds));
1855 	dsl_pool_config_enter(dp, FTAG);
1856 	VERIFY0(dmu_objset_from_ds(ds, &os));
1857 	dsl_pool_config_exit(dp, FTAG);
1858 
1859 	err = zfsvfs_init(zfsvfs, os);
1860 	if (err != 0)
1861 		goto bail;
1862 
1863 	ds->ds_dir->dd_activity_cancelled = B_FALSE;
1864 	VERIFY(zfsvfs_setup(zfsvfs, B_FALSE) == 0);
1865 
1866 	zfs_set_fuid_feature(zfsvfs);
1867 	zfsvfs->z_rollback_time = jiffies;
1868 
1869 	/*
1870 	 * Attempt to re-establish all the active inodes with their
1871 	 * dbufs.  If a zfs_rezget() fails, then we unhash the inode
1872 	 * and mark it stale.  This prevents a collision if a new
1873 	 * inode/object is created which must use the same inode
1874 	 * number.  The stale inode will be be released when the
1875 	 * VFS prunes the dentry holding the remaining references
1876 	 * on the stale inode.
1877 	 */
1878 	mutex_enter(&zfsvfs->z_znodes_lock);
1879 	for (zp = list_head(&zfsvfs->z_all_znodes); zp;
1880 	    zp = list_next(&zfsvfs->z_all_znodes, zp)) {
1881 		err2 = zfs_rezget(zp);
1882 		if (err2) {
1883 			zpl_d_drop_aliases(ZTOI(zp));
1884 			remove_inode_hash(ZTOI(zp));
1885 		}
1886 
1887 		/* see comment in zfs_suspend_fs() */
1888 		if (zp->z_suspended) {
1889 			zfs_zrele_async(zp);
1890 			zp->z_suspended = B_FALSE;
1891 		}
1892 	}
1893 	mutex_exit(&zfsvfs->z_znodes_lock);
1894 
1895 	if (!zfs_is_readonly(zfsvfs) && !zfsvfs->z_unmounted) {
1896 		/*
1897 		 * zfs_suspend_fs() could have interrupted freeing
1898 		 * of dnodes. We need to restart this freeing so
1899 		 * that we don't "leak" the space.
1900 		 */
1901 		zfs_unlinked_drain(zfsvfs);
1902 	}
1903 
1904 	/*
1905 	 * Most of the time zfs_suspend_fs is used for changing the contents
1906 	 * of the underlying dataset. ZFS rollback and receive operations
1907 	 * might create files for which negative dentries are present in
1908 	 * the cache. Since walking the dcache would require a lot of GPL-only
1909 	 * code duplication, it's much easier on these rather rare occasions
1910 	 * just to flush the whole dcache for the given dataset/filesystem.
1911 	 */
1912 	shrink_dcache_sb(zfsvfs->z_sb);
1913 
1914 bail:
1915 	if (err != 0)
1916 		zfsvfs->z_unmounted = B_TRUE;
1917 
1918 	/* release the VFS ops */
1919 	rw_exit(&zfsvfs->z_teardown_inactive_lock);
1920 	ZFS_TEARDOWN_EXIT(zfsvfs, FTAG);
1921 
1922 	if (err != 0) {
1923 		/*
1924 		 * Since we couldn't setup the sa framework, try to force
1925 		 * unmount this file system.
1926 		 */
1927 		if (zfsvfs->z_os)
1928 			(void) zfs_umount(zfsvfs->z_sb);
1929 	}
1930 	return (err);
1931 }
1932 
1933 /*
1934  * Release VOPs and unmount a suspended filesystem.
1935  */
1936 int
1937 zfs_end_fs(zfsvfs_t *zfsvfs, dsl_dataset_t *ds)
1938 {
1939 	ASSERT(ZFS_TEARDOWN_WRITE_HELD(zfsvfs));
1940 	ASSERT(RW_WRITE_HELD(&zfsvfs->z_teardown_inactive_lock));
1941 
1942 	/*
1943 	 * We already own this, so just hold and rele it to update the
1944 	 * objset_t, as the one we had before may have been evicted.
1945 	 */
1946 	objset_t *os;
1947 	VERIFY3P(ds->ds_owner, ==, zfsvfs);
1948 	VERIFY(dsl_dataset_long_held(ds));
1949 	dsl_pool_t *dp = spa_get_dsl(dsl_dataset_get_spa(ds));
1950 	dsl_pool_config_enter(dp, FTAG);
1951 	VERIFY0(dmu_objset_from_ds(ds, &os));
1952 	dsl_pool_config_exit(dp, FTAG);
1953 	zfsvfs->z_os = os;
1954 
1955 	/* release the VOPs */
1956 	rw_exit(&zfsvfs->z_teardown_inactive_lock);
1957 	ZFS_TEARDOWN_EXIT(zfsvfs, FTAG);
1958 
1959 	/*
1960 	 * Try to force unmount this file system.
1961 	 */
1962 	(void) zfs_umount(zfsvfs->z_sb);
1963 	zfsvfs->z_unmounted = B_TRUE;
1964 	return (0);
1965 }
1966 
1967 /*
1968  * Automounted snapshots rely on periodic revalidation
1969  * to defer snapshots from being automatically unmounted.
1970  */
1971 
1972 inline void
1973 zfs_exit_fs(zfsvfs_t *zfsvfs)
1974 {
1975 	if (!zfsvfs->z_issnap)
1976 		return;
1977 
1978 	if (time_after(jiffies, zfsvfs->z_snap_defer_time +
1979 	    MAX(zfs_expire_snapshot * HZ / 2, HZ))) {
1980 		zfsvfs->z_snap_defer_time = jiffies;
1981 		zfsctl_snapshot_unmount_delay(zfsvfs->z_os->os_spa,
1982 		    dmu_objset_id(zfsvfs->z_os),
1983 		    zfs_expire_snapshot);
1984 	}
1985 }
1986 
1987 int
1988 zfs_set_version(zfsvfs_t *zfsvfs, uint64_t newvers)
1989 {
1990 	int error;
1991 	objset_t *os = zfsvfs->z_os;
1992 	dmu_tx_t *tx;
1993 
1994 	if (newvers < ZPL_VERSION_INITIAL || newvers > ZPL_VERSION)
1995 		return (SET_ERROR(EINVAL));
1996 
1997 	if (newvers < zfsvfs->z_version)
1998 		return (SET_ERROR(EINVAL));
1999 
2000 	if (zfs_spa_version_map(newvers) >
2001 	    spa_version(dmu_objset_spa(zfsvfs->z_os)))
2002 		return (SET_ERROR(ENOTSUP));
2003 
2004 	tx = dmu_tx_create(os);
2005 	dmu_tx_hold_zap(tx, MASTER_NODE_OBJ, B_FALSE, ZPL_VERSION_STR);
2006 	if (newvers >= ZPL_VERSION_SA && !zfsvfs->z_use_sa) {
2007 		dmu_tx_hold_zap(tx, MASTER_NODE_OBJ, B_TRUE,
2008 		    ZFS_SA_ATTRS);
2009 		dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, FALSE, NULL);
2010 	}
2011 	error = dmu_tx_assign(tx, TXG_WAIT);
2012 	if (error) {
2013 		dmu_tx_abort(tx);
2014 		return (error);
2015 	}
2016 
2017 	error = zap_update(os, MASTER_NODE_OBJ, ZPL_VERSION_STR,
2018 	    8, 1, &newvers, tx);
2019 
2020 	if (error) {
2021 		dmu_tx_commit(tx);
2022 		return (error);
2023 	}
2024 
2025 	if (newvers >= ZPL_VERSION_SA && !zfsvfs->z_use_sa) {
2026 		uint64_t sa_obj;
2027 
2028 		ASSERT3U(spa_version(dmu_objset_spa(zfsvfs->z_os)), >=,
2029 		    SPA_VERSION_SA);
2030 		sa_obj = zap_create(os, DMU_OT_SA_MASTER_NODE,
2031 		    DMU_OT_NONE, 0, tx);
2032 
2033 		error = zap_add(os, MASTER_NODE_OBJ,
2034 		    ZFS_SA_ATTRS, 8, 1, &sa_obj, tx);
2035 		ASSERT0(error);
2036 
2037 		VERIFY(0 == sa_set_sa_object(os, sa_obj));
2038 		sa_register_update_callback(os, zfs_sa_upgrade);
2039 	}
2040 
2041 	spa_history_log_internal_ds(dmu_objset_ds(os), "upgrade", tx,
2042 	    "from %llu to %llu", zfsvfs->z_version, newvers);
2043 
2044 	dmu_tx_commit(tx);
2045 
2046 	zfsvfs->z_version = newvers;
2047 	os->os_version = newvers;
2048 
2049 	zfs_set_fuid_feature(zfsvfs);
2050 
2051 	return (0);
2052 }
2053 
2054 /*
2055  * Read a property stored within the master node.
2056  */
2057 int
2058 zfs_get_zplprop(objset_t *os, zfs_prop_t prop, uint64_t *value)
2059 {
2060 	uint64_t *cached_copy = NULL;
2061 
2062 	/*
2063 	 * Figure out where in the objset_t the cached copy would live, if it
2064 	 * is available for the requested property.
2065 	 */
2066 	if (os != NULL) {
2067 		switch (prop) {
2068 		case ZFS_PROP_VERSION:
2069 			cached_copy = &os->os_version;
2070 			break;
2071 		case ZFS_PROP_NORMALIZE:
2072 			cached_copy = &os->os_normalization;
2073 			break;
2074 		case ZFS_PROP_UTF8ONLY:
2075 			cached_copy = &os->os_utf8only;
2076 			break;
2077 		case ZFS_PROP_CASE:
2078 			cached_copy = &os->os_casesensitivity;
2079 			break;
2080 		default:
2081 			break;
2082 		}
2083 	}
2084 	if (cached_copy != NULL && *cached_copy != OBJSET_PROP_UNINITIALIZED) {
2085 		*value = *cached_copy;
2086 		return (0);
2087 	}
2088 
2089 	/*
2090 	 * If the property wasn't cached, look up the file system's value for
2091 	 * the property. For the version property, we look up a slightly
2092 	 * different string.
2093 	 */
2094 	const char *pname;
2095 	int error = ENOENT;
2096 	if (prop == ZFS_PROP_VERSION)
2097 		pname = ZPL_VERSION_STR;
2098 	else
2099 		pname = zfs_prop_to_name(prop);
2100 
2101 	if (os != NULL) {
2102 		ASSERT3U(os->os_phys->os_type, ==, DMU_OST_ZFS);
2103 		error = zap_lookup(os, MASTER_NODE_OBJ, pname, 8, 1, value);
2104 	}
2105 
2106 	if (error == ENOENT) {
2107 		/* No value set, use the default value */
2108 		switch (prop) {
2109 		case ZFS_PROP_VERSION:
2110 			*value = ZPL_VERSION;
2111 			break;
2112 		case ZFS_PROP_NORMALIZE:
2113 		case ZFS_PROP_UTF8ONLY:
2114 			*value = 0;
2115 			break;
2116 		case ZFS_PROP_CASE:
2117 			*value = ZFS_CASE_SENSITIVE;
2118 			break;
2119 		case ZFS_PROP_ACLTYPE:
2120 			*value = ZFS_ACLTYPE_OFF;
2121 			break;
2122 		default:
2123 			return (error);
2124 		}
2125 		error = 0;
2126 	}
2127 
2128 	/*
2129 	 * If one of the methods for getting the property value above worked,
2130 	 * copy it into the objset_t's cache.
2131 	 */
2132 	if (error == 0 && cached_copy != NULL) {
2133 		*cached_copy = *value;
2134 	}
2135 
2136 	return (error);
2137 }
2138 
2139 /*
2140  * Return true if the corresponding vfs's unmounted flag is set.
2141  * Otherwise return false.
2142  * If this function returns true we know VFS unmount has been initiated.
2143  */
2144 boolean_t
2145 zfs_get_vfs_flag_unmounted(objset_t *os)
2146 {
2147 	zfsvfs_t *zfvp;
2148 	boolean_t unmounted = B_FALSE;
2149 
2150 	ASSERT(dmu_objset_type(os) == DMU_OST_ZFS);
2151 
2152 	mutex_enter(&os->os_user_ptr_lock);
2153 	zfvp = dmu_objset_get_user(os);
2154 	if (zfvp != NULL && zfvp->z_unmounted)
2155 		unmounted = B_TRUE;
2156 	mutex_exit(&os->os_user_ptr_lock);
2157 
2158 	return (unmounted);
2159 }
2160 
2161 void
2162 zfsvfs_update_fromname(const char *oldname, const char *newname)
2163 {
2164 	/*
2165 	 * We don't need to do anything here, the devname is always current by
2166 	 * virtue of zfsvfs->z_sb->s_op->show_devname.
2167 	 */
2168 	(void) oldname, (void) newname;
2169 }
2170 
2171 void
2172 zfs_init(void)
2173 {
2174 	zfsctl_init();
2175 	zfs_znode_init();
2176 	dmu_objset_register_type(DMU_OST_ZFS, zpl_get_file_info);
2177 	register_filesystem(&zpl_fs_type);
2178 }
2179 
2180 void
2181 zfs_fini(void)
2182 {
2183 	/*
2184 	 * we don't use outstanding because zpl_posix_acl_free might add more.
2185 	 */
2186 	taskq_wait(system_delay_taskq);
2187 	taskq_wait(system_taskq);
2188 	unregister_filesystem(&zpl_fs_type);
2189 	zfs_znode_fini();
2190 	zfsctl_fini();
2191 }
2192 
2193 #if defined(_KERNEL)
2194 EXPORT_SYMBOL(zfs_suspend_fs);
2195 EXPORT_SYMBOL(zfs_resume_fs);
2196 EXPORT_SYMBOL(zfs_set_version);
2197 EXPORT_SYMBOL(zfsvfs_create);
2198 EXPORT_SYMBOL(zfsvfs_free);
2199 EXPORT_SYMBOL(zfs_is_readonly);
2200 EXPORT_SYMBOL(zfs_domount);
2201 EXPORT_SYMBOL(zfs_preumount);
2202 EXPORT_SYMBOL(zfs_umount);
2203 EXPORT_SYMBOL(zfs_remount);
2204 EXPORT_SYMBOL(zfs_statvfs);
2205 EXPORT_SYMBOL(zfs_vget);
2206 EXPORT_SYMBOL(zfs_prune);
2207 #endif
2208