xref: /freebsd/sys/contrib/openzfs/module/os/linux/zfs/zfs_vfsops.c (revision ba3c1f5972d7b90feb6e6da47905ff2757e0fe57)
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 		if (setpoint)
612 			(void) strcpy(setpoint, "temporary");
613 		*val = tmp;
614 	}
615 	return (0);
616 }
617 
618 /*
619  * Associate this zfsvfs with the given objset, which must be owned.
620  * This will cache a bunch of on-disk state from the objset in the
621  * zfsvfs.
622  */
623 static int
624 zfsvfs_init(zfsvfs_t *zfsvfs, objset_t *os)
625 {
626 	int error;
627 	uint64_t val;
628 
629 	zfsvfs->z_max_blksz = SPA_OLD_MAXBLOCKSIZE;
630 	zfsvfs->z_show_ctldir = ZFS_SNAPDIR_VISIBLE;
631 	zfsvfs->z_os = os;
632 
633 	error = zfs_get_zplprop(os, ZFS_PROP_VERSION, &zfsvfs->z_version);
634 	if (error != 0)
635 		return (error);
636 	if (zfsvfs->z_version >
637 	    zfs_zpl_version_map(spa_version(dmu_objset_spa(os)))) {
638 		(void) printk("Can't mount a version %lld file system "
639 		    "on a version %lld pool\n. Pool must be upgraded to mount "
640 		    "this file system.\n", (u_longlong_t)zfsvfs->z_version,
641 		    (u_longlong_t)spa_version(dmu_objset_spa(os)));
642 		return (SET_ERROR(ENOTSUP));
643 	}
644 	error = zfs_get_zplprop(os, ZFS_PROP_NORMALIZE, &val);
645 	if (error != 0)
646 		return (error);
647 	zfsvfs->z_norm = (int)val;
648 
649 	error = zfs_get_zplprop(os, ZFS_PROP_UTF8ONLY, &val);
650 	if (error != 0)
651 		return (error);
652 	zfsvfs->z_utf8 = (val != 0);
653 
654 	error = zfs_get_zplprop(os, ZFS_PROP_CASE, &val);
655 	if (error != 0)
656 		return (error);
657 	zfsvfs->z_case = (uint_t)val;
658 
659 	if ((error = zfs_get_zplprop(os, ZFS_PROP_ACLTYPE, &val)) != 0)
660 		return (error);
661 	zfsvfs->z_acl_type = (uint_t)val;
662 
663 	/*
664 	 * Fold case on file systems that are always or sometimes case
665 	 * insensitive.
666 	 */
667 	if (zfsvfs->z_case == ZFS_CASE_INSENSITIVE ||
668 	    zfsvfs->z_case == ZFS_CASE_MIXED)
669 		zfsvfs->z_norm |= U8_TEXTPREP_TOUPPER;
670 
671 	zfsvfs->z_use_fuids = USE_FUIDS(zfsvfs->z_version, zfsvfs->z_os);
672 	zfsvfs->z_use_sa = USE_SA(zfsvfs->z_version, zfsvfs->z_os);
673 
674 	uint64_t sa_obj = 0;
675 	if (zfsvfs->z_use_sa) {
676 		/* should either have both of these objects or none */
677 		error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_SA_ATTRS, 8, 1,
678 		    &sa_obj);
679 		if (error != 0)
680 			return (error);
681 
682 		error = zfs_get_zplprop(os, ZFS_PROP_XATTR, &val);
683 		if ((error == 0) && (val == ZFS_XATTR_SA))
684 			zfsvfs->z_xattr_sa = B_TRUE;
685 	}
686 
687 	error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_ROOT_OBJ, 8, 1,
688 	    &zfsvfs->z_root);
689 	if (error != 0)
690 		return (error);
691 	ASSERT(zfsvfs->z_root != 0);
692 
693 	error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_UNLINKED_SET, 8, 1,
694 	    &zfsvfs->z_unlinkedobj);
695 	if (error != 0)
696 		return (error);
697 
698 	error = zap_lookup(os, MASTER_NODE_OBJ,
699 	    zfs_userquota_prop_prefixes[ZFS_PROP_USERQUOTA],
700 	    8, 1, &zfsvfs->z_userquota_obj);
701 	if (error == ENOENT)
702 		zfsvfs->z_userquota_obj = 0;
703 	else if (error != 0)
704 		return (error);
705 
706 	error = zap_lookup(os, MASTER_NODE_OBJ,
707 	    zfs_userquota_prop_prefixes[ZFS_PROP_GROUPQUOTA],
708 	    8, 1, &zfsvfs->z_groupquota_obj);
709 	if (error == ENOENT)
710 		zfsvfs->z_groupquota_obj = 0;
711 	else if (error != 0)
712 		return (error);
713 
714 	error = zap_lookup(os, MASTER_NODE_OBJ,
715 	    zfs_userquota_prop_prefixes[ZFS_PROP_PROJECTQUOTA],
716 	    8, 1, &zfsvfs->z_projectquota_obj);
717 	if (error == ENOENT)
718 		zfsvfs->z_projectquota_obj = 0;
719 	else if (error != 0)
720 		return (error);
721 
722 	error = zap_lookup(os, MASTER_NODE_OBJ,
723 	    zfs_userquota_prop_prefixes[ZFS_PROP_USEROBJQUOTA],
724 	    8, 1, &zfsvfs->z_userobjquota_obj);
725 	if (error == ENOENT)
726 		zfsvfs->z_userobjquota_obj = 0;
727 	else if (error != 0)
728 		return (error);
729 
730 	error = zap_lookup(os, MASTER_NODE_OBJ,
731 	    zfs_userquota_prop_prefixes[ZFS_PROP_GROUPOBJQUOTA],
732 	    8, 1, &zfsvfs->z_groupobjquota_obj);
733 	if (error == ENOENT)
734 		zfsvfs->z_groupobjquota_obj = 0;
735 	else if (error != 0)
736 		return (error);
737 
738 	error = zap_lookup(os, MASTER_NODE_OBJ,
739 	    zfs_userquota_prop_prefixes[ZFS_PROP_PROJECTOBJQUOTA],
740 	    8, 1, &zfsvfs->z_projectobjquota_obj);
741 	if (error == ENOENT)
742 		zfsvfs->z_projectobjquota_obj = 0;
743 	else if (error != 0)
744 		return (error);
745 
746 	error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_FUID_TABLES, 8, 1,
747 	    &zfsvfs->z_fuid_obj);
748 	if (error == ENOENT)
749 		zfsvfs->z_fuid_obj = 0;
750 	else if (error != 0)
751 		return (error);
752 
753 	error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_SHARES_DIR, 8, 1,
754 	    &zfsvfs->z_shares_dir);
755 	if (error == ENOENT)
756 		zfsvfs->z_shares_dir = 0;
757 	else if (error != 0)
758 		return (error);
759 
760 	error = sa_setup(os, sa_obj, zfs_attr_table, ZPL_END,
761 	    &zfsvfs->z_attr_table);
762 	if (error != 0)
763 		return (error);
764 
765 	if (zfsvfs->z_version >= ZPL_VERSION_SA)
766 		sa_register_update_callback(os, zfs_sa_upgrade);
767 
768 	return (0);
769 }
770 
771 int
772 zfsvfs_create(const char *osname, boolean_t readonly, zfsvfs_t **zfvp)
773 {
774 	objset_t *os;
775 	zfsvfs_t *zfsvfs;
776 	int error;
777 	boolean_t ro = (readonly || (strchr(osname, '@') != NULL));
778 
779 	zfsvfs = kmem_zalloc(sizeof (zfsvfs_t), KM_SLEEP);
780 
781 	error = dmu_objset_own(osname, DMU_OST_ZFS, ro, B_TRUE, zfsvfs, &os);
782 	if (error != 0) {
783 		kmem_free(zfsvfs, sizeof (zfsvfs_t));
784 		return (error);
785 	}
786 
787 	error = zfsvfs_create_impl(zfvp, zfsvfs, os);
788 
789 	return (error);
790 }
791 
792 
793 /*
794  * Note: zfsvfs is assumed to be malloc'd, and will be freed by this function
795  * on a failure.  Do not pass in a statically allocated zfsvfs.
796  */
797 int
798 zfsvfs_create_impl(zfsvfs_t **zfvp, zfsvfs_t *zfsvfs, objset_t *os)
799 {
800 	int error;
801 
802 	zfsvfs->z_vfs = NULL;
803 	zfsvfs->z_sb = NULL;
804 	zfsvfs->z_parent = zfsvfs;
805 
806 	mutex_init(&zfsvfs->z_znodes_lock, NULL, MUTEX_DEFAULT, NULL);
807 	mutex_init(&zfsvfs->z_lock, NULL, MUTEX_DEFAULT, NULL);
808 	list_create(&zfsvfs->z_all_znodes, sizeof (znode_t),
809 	    offsetof(znode_t, z_link_node));
810 	ZFS_TEARDOWN_INIT(zfsvfs);
811 	rw_init(&zfsvfs->z_teardown_inactive_lock, NULL, RW_DEFAULT, NULL);
812 	rw_init(&zfsvfs->z_fuid_lock, NULL, RW_DEFAULT, NULL);
813 
814 	int size = MIN(1 << (highbit64(zfs_object_mutex_size) - 1),
815 	    ZFS_OBJ_MTX_MAX);
816 	zfsvfs->z_hold_size = size;
817 	zfsvfs->z_hold_trees = vmem_zalloc(sizeof (avl_tree_t) * size,
818 	    KM_SLEEP);
819 	zfsvfs->z_hold_locks = vmem_zalloc(sizeof (kmutex_t) * size, KM_SLEEP);
820 	for (int i = 0; i != size; i++) {
821 		avl_create(&zfsvfs->z_hold_trees[i], zfs_znode_hold_compare,
822 		    sizeof (znode_hold_t), offsetof(znode_hold_t, zh_node));
823 		mutex_init(&zfsvfs->z_hold_locks[i], NULL, MUTEX_DEFAULT, NULL);
824 	}
825 
826 	error = zfsvfs_init(zfsvfs, os);
827 	if (error != 0) {
828 		dmu_objset_disown(os, B_TRUE, zfsvfs);
829 		*zfvp = NULL;
830 		zfsvfs_free(zfsvfs);
831 		return (error);
832 	}
833 
834 	zfsvfs->z_drain_task = TASKQID_INVALID;
835 	zfsvfs->z_draining = B_FALSE;
836 	zfsvfs->z_drain_cancel = B_TRUE;
837 
838 	*zfvp = zfsvfs;
839 	return (0);
840 }
841 
842 static int
843 zfsvfs_setup(zfsvfs_t *zfsvfs, boolean_t mounting)
844 {
845 	int error;
846 	boolean_t readonly = zfs_is_readonly(zfsvfs);
847 
848 	error = zfs_register_callbacks(zfsvfs->z_vfs);
849 	if (error)
850 		return (error);
851 
852 	/*
853 	 * If we are not mounting (ie: online recv), then we don't
854 	 * have to worry about replaying the log as we blocked all
855 	 * operations out since we closed the ZIL.
856 	 */
857 	if (mounting) {
858 		ASSERT3P(zfsvfs->z_kstat.dk_kstats, ==, NULL);
859 		error = dataset_kstats_create(&zfsvfs->z_kstat, zfsvfs->z_os);
860 		if (error)
861 			return (error);
862 		zfsvfs->z_log = zil_open(zfsvfs->z_os, zfs_get_data,
863 		    &zfsvfs->z_kstat.dk_zil_sums);
864 
865 		/*
866 		 * During replay we remove the read only flag to
867 		 * allow replays to succeed.
868 		 */
869 		if (readonly != 0) {
870 			readonly_changed_cb(zfsvfs, B_FALSE);
871 		} else {
872 			zap_stats_t zs;
873 			if (zap_get_stats(zfsvfs->z_os, zfsvfs->z_unlinkedobj,
874 			    &zs) == 0) {
875 				dataset_kstats_update_nunlinks_kstat(
876 				    &zfsvfs->z_kstat, zs.zs_num_entries);
877 				dprintf_ds(zfsvfs->z_os->os_dsl_dataset,
878 				    "num_entries in unlinked set: %llu",
879 				    zs.zs_num_entries);
880 			}
881 			zfs_unlinked_drain(zfsvfs);
882 			dsl_dir_t *dd = zfsvfs->z_os->os_dsl_dataset->ds_dir;
883 			dd->dd_activity_cancelled = B_FALSE;
884 		}
885 
886 		/*
887 		 * Parse and replay the intent log.
888 		 *
889 		 * Because of ziltest, this must be done after
890 		 * zfs_unlinked_drain().  (Further note: ziltest
891 		 * doesn't use readonly mounts, where
892 		 * zfs_unlinked_drain() isn't called.)  This is because
893 		 * ziltest causes spa_sync() to think it's committed,
894 		 * but actually it is not, so the intent log contains
895 		 * many txg's worth of changes.
896 		 *
897 		 * In particular, if object N is in the unlinked set in
898 		 * the last txg to actually sync, then it could be
899 		 * actually freed in a later txg and then reallocated
900 		 * in a yet later txg.  This would write a "create
901 		 * object N" record to the intent log.  Normally, this
902 		 * would be fine because the spa_sync() would have
903 		 * written out the fact that object N is free, before
904 		 * we could write the "create object N" intent log
905 		 * record.
906 		 *
907 		 * But when we are in ziltest mode, we advance the "open
908 		 * txg" without actually spa_sync()-ing the changes to
909 		 * disk.  So we would see that object N is still
910 		 * allocated and in the unlinked set, and there is an
911 		 * intent log record saying to allocate it.
912 		 */
913 		if (spa_writeable(dmu_objset_spa(zfsvfs->z_os))) {
914 			if (zil_replay_disable) {
915 				zil_destroy(zfsvfs->z_log, B_FALSE);
916 			} else {
917 				zfsvfs->z_replay = B_TRUE;
918 				zil_replay(zfsvfs->z_os, zfsvfs,
919 				    zfs_replay_vector);
920 				zfsvfs->z_replay = B_FALSE;
921 			}
922 		}
923 
924 		/* restore readonly bit */
925 		if (readonly != 0)
926 			readonly_changed_cb(zfsvfs, B_TRUE);
927 	} else {
928 		ASSERT3P(zfsvfs->z_kstat.dk_kstats, !=, NULL);
929 		zfsvfs->z_log = zil_open(zfsvfs->z_os, zfs_get_data,
930 		    &zfsvfs->z_kstat.dk_zil_sums);
931 	}
932 
933 	/*
934 	 * Set the objset user_ptr to track its zfsvfs.
935 	 */
936 	mutex_enter(&zfsvfs->z_os->os_user_ptr_lock);
937 	dmu_objset_set_user(zfsvfs->z_os, zfsvfs);
938 	mutex_exit(&zfsvfs->z_os->os_user_ptr_lock);
939 
940 	return (0);
941 }
942 
943 void
944 zfsvfs_free(zfsvfs_t *zfsvfs)
945 {
946 	int i, size = zfsvfs->z_hold_size;
947 
948 	zfs_fuid_destroy(zfsvfs);
949 
950 	mutex_destroy(&zfsvfs->z_znodes_lock);
951 	mutex_destroy(&zfsvfs->z_lock);
952 	list_destroy(&zfsvfs->z_all_znodes);
953 	ZFS_TEARDOWN_DESTROY(zfsvfs);
954 	rw_destroy(&zfsvfs->z_teardown_inactive_lock);
955 	rw_destroy(&zfsvfs->z_fuid_lock);
956 	for (i = 0; i != size; i++) {
957 		avl_destroy(&zfsvfs->z_hold_trees[i]);
958 		mutex_destroy(&zfsvfs->z_hold_locks[i]);
959 	}
960 	vmem_free(zfsvfs->z_hold_trees, sizeof (avl_tree_t) * size);
961 	vmem_free(zfsvfs->z_hold_locks, sizeof (kmutex_t) * size);
962 	zfsvfs_vfs_free(zfsvfs->z_vfs);
963 	dataset_kstats_destroy(&zfsvfs->z_kstat);
964 	kmem_free(zfsvfs, sizeof (zfsvfs_t));
965 }
966 
967 static void
968 zfs_set_fuid_feature(zfsvfs_t *zfsvfs)
969 {
970 	zfsvfs->z_use_fuids = USE_FUIDS(zfsvfs->z_version, zfsvfs->z_os);
971 	zfsvfs->z_use_sa = USE_SA(zfsvfs->z_version, zfsvfs->z_os);
972 }
973 
974 static void
975 zfs_unregister_callbacks(zfsvfs_t *zfsvfs)
976 {
977 	objset_t *os = zfsvfs->z_os;
978 
979 	if (!dmu_objset_is_snapshot(os))
980 		dsl_prop_unregister_all(dmu_objset_ds(os), zfsvfs);
981 }
982 
983 #ifdef HAVE_MLSLABEL
984 /*
985  * Check that the hex label string is appropriate for the dataset being
986  * mounted into the global_zone proper.
987  *
988  * Return an error if the hex label string is not default or
989  * admin_low/admin_high.  For admin_low labels, the corresponding
990  * dataset must be readonly.
991  */
992 int
993 zfs_check_global_label(const char *dsname, const char *hexsl)
994 {
995 	if (strcasecmp(hexsl, ZFS_MLSLABEL_DEFAULT) == 0)
996 		return (0);
997 	if (strcasecmp(hexsl, ADMIN_HIGH) == 0)
998 		return (0);
999 	if (strcasecmp(hexsl, ADMIN_LOW) == 0) {
1000 		/* must be readonly */
1001 		uint64_t rdonly;
1002 
1003 		if (dsl_prop_get_integer(dsname,
1004 		    zfs_prop_to_name(ZFS_PROP_READONLY), &rdonly, NULL))
1005 			return (SET_ERROR(EACCES));
1006 		return (rdonly ? 0 : SET_ERROR(EACCES));
1007 	}
1008 	return (SET_ERROR(EACCES));
1009 }
1010 #endif /* HAVE_MLSLABEL */
1011 
1012 static int
1013 zfs_statfs_project(zfsvfs_t *zfsvfs, znode_t *zp, struct kstatfs *statp,
1014     uint32_t bshift)
1015 {
1016 	char buf[20 + DMU_OBJACCT_PREFIX_LEN];
1017 	uint64_t offset = DMU_OBJACCT_PREFIX_LEN;
1018 	uint64_t quota;
1019 	uint64_t used;
1020 	int err;
1021 
1022 	strlcpy(buf, DMU_OBJACCT_PREFIX, DMU_OBJACCT_PREFIX_LEN + 1);
1023 	err = zfs_id_to_fuidstr(zfsvfs, NULL, zp->z_projid, buf + offset,
1024 	    sizeof (buf) - offset, B_FALSE);
1025 	if (err)
1026 		return (err);
1027 
1028 	if (zfsvfs->z_projectquota_obj == 0)
1029 		goto objs;
1030 
1031 	err = zap_lookup(zfsvfs->z_os, zfsvfs->z_projectquota_obj,
1032 	    buf + offset, 8, 1, &quota);
1033 	if (err == ENOENT)
1034 		goto objs;
1035 	else if (err)
1036 		return (err);
1037 
1038 	err = zap_lookup(zfsvfs->z_os, DMU_PROJECTUSED_OBJECT,
1039 	    buf + offset, 8, 1, &used);
1040 	if (unlikely(err == ENOENT)) {
1041 		uint32_t blksize;
1042 		u_longlong_t nblocks;
1043 
1044 		/*
1045 		 * Quota accounting is async, so it is possible race case.
1046 		 * There is at least one object with the given project ID.
1047 		 */
1048 		sa_object_size(zp->z_sa_hdl, &blksize, &nblocks);
1049 		if (unlikely(zp->z_blksz == 0))
1050 			blksize = zfsvfs->z_max_blksz;
1051 
1052 		used = blksize * nblocks;
1053 	} else if (err) {
1054 		return (err);
1055 	}
1056 
1057 	statp->f_blocks = quota >> bshift;
1058 	statp->f_bfree = (quota > used) ? ((quota - used) >> bshift) : 0;
1059 	statp->f_bavail = statp->f_bfree;
1060 
1061 objs:
1062 	if (zfsvfs->z_projectobjquota_obj == 0)
1063 		return (0);
1064 
1065 	err = zap_lookup(zfsvfs->z_os, zfsvfs->z_projectobjquota_obj,
1066 	    buf + offset, 8, 1, &quota);
1067 	if (err == ENOENT)
1068 		return (0);
1069 	else if (err)
1070 		return (err);
1071 
1072 	err = zap_lookup(zfsvfs->z_os, DMU_PROJECTUSED_OBJECT,
1073 	    buf, 8, 1, &used);
1074 	if (unlikely(err == ENOENT)) {
1075 		/*
1076 		 * Quota accounting is async, so it is possible race case.
1077 		 * There is at least one object with the given project ID.
1078 		 */
1079 		used = 1;
1080 	} else if (err) {
1081 		return (err);
1082 	}
1083 
1084 	statp->f_files = quota;
1085 	statp->f_ffree = (quota > used) ? (quota - used) : 0;
1086 
1087 	return (0);
1088 }
1089 
1090 int
1091 zfs_statvfs(struct inode *ip, struct kstatfs *statp)
1092 {
1093 	zfsvfs_t *zfsvfs = ITOZSB(ip);
1094 	uint64_t refdbytes, availbytes, usedobjs, availobjs;
1095 	int err = 0;
1096 
1097 	if ((err = zfs_enter(zfsvfs, FTAG)) != 0)
1098 		return (err);
1099 
1100 	dmu_objset_space(zfsvfs->z_os,
1101 	    &refdbytes, &availbytes, &usedobjs, &availobjs);
1102 
1103 	uint64_t fsid = dmu_objset_fsid_guid(zfsvfs->z_os);
1104 	/*
1105 	 * The underlying storage pool actually uses multiple block
1106 	 * size.  Under Solaris frsize (fragment size) is reported as
1107 	 * the smallest block size we support, and bsize (block size)
1108 	 * as the filesystem's maximum block size.  Unfortunately,
1109 	 * under Linux the fragment size and block size are often used
1110 	 * interchangeably.  Thus we are forced to report both of them
1111 	 * as the filesystem's maximum block size.
1112 	 */
1113 	statp->f_frsize = zfsvfs->z_max_blksz;
1114 	statp->f_bsize = zfsvfs->z_max_blksz;
1115 	uint32_t bshift = fls(statp->f_bsize) - 1;
1116 
1117 	/*
1118 	 * The following report "total" blocks of various kinds in
1119 	 * the file system, but reported in terms of f_bsize - the
1120 	 * "preferred" size.
1121 	 */
1122 
1123 	/* Round up so we never have a filesystem using 0 blocks. */
1124 	refdbytes = P2ROUNDUP(refdbytes, statp->f_bsize);
1125 	statp->f_blocks = (refdbytes + availbytes) >> bshift;
1126 	statp->f_bfree = availbytes >> bshift;
1127 	statp->f_bavail = statp->f_bfree; /* no root reservation */
1128 
1129 	/*
1130 	 * statvfs() should really be called statufs(), because it assumes
1131 	 * static metadata.  ZFS doesn't preallocate files, so the best
1132 	 * we can do is report the max that could possibly fit in f_files,
1133 	 * and that minus the number actually used in f_ffree.
1134 	 * For f_ffree, report the smaller of the number of objects available
1135 	 * and the number of blocks (each object will take at least a block).
1136 	 */
1137 	statp->f_ffree = MIN(availobjs, availbytes >> DNODE_SHIFT);
1138 	statp->f_files = statp->f_ffree + usedobjs;
1139 	statp->f_fsid.val[0] = (uint32_t)fsid;
1140 	statp->f_fsid.val[1] = (uint32_t)(fsid >> 32);
1141 	statp->f_type = ZFS_SUPER_MAGIC;
1142 	statp->f_namelen = MAXNAMELEN - 1;
1143 
1144 	/*
1145 	 * We have all of 40 characters to stuff a string here.
1146 	 * Is there anything useful we could/should provide?
1147 	 */
1148 	memset(statp->f_spare, 0, sizeof (statp->f_spare));
1149 
1150 	if (dmu_objset_projectquota_enabled(zfsvfs->z_os) &&
1151 	    dmu_objset_projectquota_present(zfsvfs->z_os)) {
1152 		znode_t *zp = ITOZ(ip);
1153 
1154 		if (zp->z_pflags & ZFS_PROJINHERIT && zp->z_projid &&
1155 		    zpl_is_valid_projid(zp->z_projid))
1156 			err = zfs_statfs_project(zfsvfs, zp, statp, bshift);
1157 	}
1158 
1159 	zfs_exit(zfsvfs, FTAG);
1160 	return (err);
1161 }
1162 
1163 static int
1164 zfs_root(zfsvfs_t *zfsvfs, struct inode **ipp)
1165 {
1166 	znode_t *rootzp;
1167 	int error;
1168 
1169 	if ((error = zfs_enter(zfsvfs, FTAG)) != 0)
1170 		return (error);
1171 
1172 	error = zfs_zget(zfsvfs, zfsvfs->z_root, &rootzp);
1173 	if (error == 0)
1174 		*ipp = ZTOI(rootzp);
1175 
1176 	zfs_exit(zfsvfs, FTAG);
1177 	return (error);
1178 }
1179 
1180 /*
1181  * Linux kernels older than 3.1 do not support a per-filesystem shrinker.
1182  * To accommodate this we must improvise and manually walk the list of znodes
1183  * attempting to prune dentries in order to be able to drop the inodes.
1184  *
1185  * To avoid scanning the same znodes multiple times they are always rotated
1186  * to the end of the z_all_znodes list.  New znodes are inserted at the
1187  * end of the list so we're always scanning the oldest znodes first.
1188  */
1189 static int
1190 zfs_prune_aliases(zfsvfs_t *zfsvfs, unsigned long nr_to_scan)
1191 {
1192 	znode_t **zp_array, *zp;
1193 	int max_array = MIN(nr_to_scan, PAGE_SIZE * 8 / sizeof (znode_t *));
1194 	int objects = 0;
1195 	int i = 0, j = 0;
1196 
1197 	zp_array = vmem_zalloc(max_array * sizeof (znode_t *), KM_SLEEP);
1198 
1199 	mutex_enter(&zfsvfs->z_znodes_lock);
1200 	while ((zp = list_head(&zfsvfs->z_all_znodes)) != NULL) {
1201 
1202 		if ((i++ > nr_to_scan) || (j >= max_array))
1203 			break;
1204 
1205 		ASSERT(list_link_active(&zp->z_link_node));
1206 		list_remove(&zfsvfs->z_all_znodes, zp);
1207 		list_insert_tail(&zfsvfs->z_all_znodes, zp);
1208 
1209 		/* Skip active znodes and .zfs entries */
1210 		if (MUTEX_HELD(&zp->z_lock) || zp->z_is_ctldir)
1211 			continue;
1212 
1213 		if (igrab(ZTOI(zp)) == NULL)
1214 			continue;
1215 
1216 		zp_array[j] = zp;
1217 		j++;
1218 	}
1219 	mutex_exit(&zfsvfs->z_znodes_lock);
1220 
1221 	for (i = 0; i < j; i++) {
1222 		zp = zp_array[i];
1223 
1224 		ASSERT3P(zp, !=, NULL);
1225 		d_prune_aliases(ZTOI(zp));
1226 
1227 		if (atomic_read(&ZTOI(zp)->i_count) == 1)
1228 			objects++;
1229 
1230 		zrele(zp);
1231 	}
1232 
1233 	vmem_free(zp_array, max_array * sizeof (znode_t *));
1234 
1235 	return (objects);
1236 }
1237 
1238 /*
1239  * The ARC has requested that the filesystem drop entries from the dentry
1240  * and inode caches.  This can occur when the ARC needs to free meta data
1241  * blocks but can't because they are all pinned by entries in these caches.
1242  */
1243 int
1244 zfs_prune(struct super_block *sb, unsigned long nr_to_scan, int *objects)
1245 {
1246 	zfsvfs_t *zfsvfs = sb->s_fs_info;
1247 	int error = 0;
1248 	struct shrinker *shrinker = &sb->s_shrink;
1249 	struct shrink_control sc = {
1250 		.nr_to_scan = nr_to_scan,
1251 		.gfp_mask = GFP_KERNEL,
1252 	};
1253 
1254 	if ((error = zfs_enter(zfsvfs, FTAG)) != 0)
1255 		return (error);
1256 
1257 #if defined(HAVE_SPLIT_SHRINKER_CALLBACK) && \
1258 	defined(SHRINK_CONTROL_HAS_NID) && \
1259 	defined(SHRINKER_NUMA_AWARE)
1260 	if (sb->s_shrink.flags & SHRINKER_NUMA_AWARE) {
1261 		*objects = 0;
1262 		for_each_online_node(sc.nid) {
1263 			*objects += (*shrinker->scan_objects)(shrinker, &sc);
1264 			/*
1265 			 * reset sc.nr_to_scan, modified by
1266 			 * scan_objects == super_cache_scan
1267 			 */
1268 			sc.nr_to_scan = nr_to_scan;
1269 		}
1270 	} else {
1271 			*objects = (*shrinker->scan_objects)(shrinker, &sc);
1272 	}
1273 
1274 #elif defined(HAVE_SPLIT_SHRINKER_CALLBACK)
1275 	*objects = (*shrinker->scan_objects)(shrinker, &sc);
1276 #elif defined(HAVE_SINGLE_SHRINKER_CALLBACK)
1277 	*objects = (*shrinker->shrink)(shrinker, &sc);
1278 #elif defined(HAVE_D_PRUNE_ALIASES)
1279 #define	D_PRUNE_ALIASES_IS_DEFAULT
1280 	*objects = zfs_prune_aliases(zfsvfs, nr_to_scan);
1281 #else
1282 #error "No available dentry and inode cache pruning mechanism."
1283 #endif
1284 
1285 #if defined(HAVE_D_PRUNE_ALIASES) && !defined(D_PRUNE_ALIASES_IS_DEFAULT)
1286 #undef	D_PRUNE_ALIASES_IS_DEFAULT
1287 	/*
1288 	 * Fall back to zfs_prune_aliases if the kernel's per-superblock
1289 	 * shrinker couldn't free anything, possibly due to the inodes being
1290 	 * allocated in a different memcg.
1291 	 */
1292 	if (*objects == 0)
1293 		*objects = zfs_prune_aliases(zfsvfs, nr_to_scan);
1294 #endif
1295 
1296 	zfs_exit(zfsvfs, FTAG);
1297 
1298 	dprintf_ds(zfsvfs->z_os->os_dsl_dataset,
1299 	    "pruning, nr_to_scan=%lu objects=%d error=%d\n",
1300 	    nr_to_scan, *objects, error);
1301 
1302 	return (error);
1303 }
1304 
1305 /*
1306  * Teardown the zfsvfs_t.
1307  *
1308  * Note, if 'unmounting' is FALSE, we return with the 'z_teardown_lock'
1309  * and 'z_teardown_inactive_lock' held.
1310  */
1311 static int
1312 zfsvfs_teardown(zfsvfs_t *zfsvfs, boolean_t unmounting)
1313 {
1314 	znode_t	*zp;
1315 
1316 	zfs_unlinked_drain_stop_wait(zfsvfs);
1317 
1318 	/*
1319 	 * If someone has not already unmounted this file system,
1320 	 * drain the zrele_taskq to ensure all active references to the
1321 	 * zfsvfs_t have been handled only then can it be safely destroyed.
1322 	 */
1323 	if (zfsvfs->z_os) {
1324 		/*
1325 		 * If we're unmounting we have to wait for the list to
1326 		 * drain completely.
1327 		 *
1328 		 * If we're not unmounting there's no guarantee the list
1329 		 * will drain completely, but iputs run from the taskq
1330 		 * may add the parents of dir-based xattrs to the taskq
1331 		 * so we want to wait for these.
1332 		 *
1333 		 * We can safely read z_nr_znodes without locking because the
1334 		 * VFS has already blocked operations which add to the
1335 		 * z_all_znodes list and thus increment z_nr_znodes.
1336 		 */
1337 		int round = 0;
1338 		while (zfsvfs->z_nr_znodes > 0) {
1339 			taskq_wait_outstanding(dsl_pool_zrele_taskq(
1340 			    dmu_objset_pool(zfsvfs->z_os)), 0);
1341 			if (++round > 1 && !unmounting)
1342 				break;
1343 		}
1344 	}
1345 
1346 	ZFS_TEARDOWN_ENTER_WRITE(zfsvfs, FTAG);
1347 
1348 	if (!unmounting) {
1349 		/*
1350 		 * We purge the parent filesystem's super block as the
1351 		 * parent filesystem and all of its snapshots have their
1352 		 * inode's super block set to the parent's filesystem's
1353 		 * super block.  Note,  'z_parent' is self referential
1354 		 * for non-snapshots.
1355 		 */
1356 		shrink_dcache_sb(zfsvfs->z_parent->z_sb);
1357 	}
1358 
1359 	/*
1360 	 * Close the zil. NB: Can't close the zil while zfs_inactive
1361 	 * threads are blocked as zil_close can call zfs_inactive.
1362 	 */
1363 	if (zfsvfs->z_log) {
1364 		zil_close(zfsvfs->z_log);
1365 		zfsvfs->z_log = NULL;
1366 	}
1367 
1368 	rw_enter(&zfsvfs->z_teardown_inactive_lock, RW_WRITER);
1369 
1370 	/*
1371 	 * If we are not unmounting (ie: online recv) and someone already
1372 	 * unmounted this file system while we were doing the switcheroo,
1373 	 * or a reopen of z_os failed then just bail out now.
1374 	 */
1375 	if (!unmounting && (zfsvfs->z_unmounted || zfsvfs->z_os == NULL)) {
1376 		rw_exit(&zfsvfs->z_teardown_inactive_lock);
1377 		ZFS_TEARDOWN_EXIT(zfsvfs, FTAG);
1378 		return (SET_ERROR(EIO));
1379 	}
1380 
1381 	/*
1382 	 * At this point there are no VFS ops active, and any new VFS ops
1383 	 * will fail with EIO since we have z_teardown_lock for writer (only
1384 	 * relevant for forced unmount).
1385 	 *
1386 	 * Release all holds on dbufs. We also grab an extra reference to all
1387 	 * the remaining inodes so that the kernel does not attempt to free
1388 	 * any inodes of a suspended fs. This can cause deadlocks since the
1389 	 * zfs_resume_fs() process may involve starting threads, which might
1390 	 * attempt to free unreferenced inodes to free up memory for the new
1391 	 * thread.
1392 	 */
1393 	if (!unmounting) {
1394 		mutex_enter(&zfsvfs->z_znodes_lock);
1395 		for (zp = list_head(&zfsvfs->z_all_znodes); zp != NULL;
1396 		    zp = list_next(&zfsvfs->z_all_znodes, zp)) {
1397 			if (zp->z_sa_hdl)
1398 				zfs_znode_dmu_fini(zp);
1399 			if (igrab(ZTOI(zp)) != NULL)
1400 				zp->z_suspended = B_TRUE;
1401 
1402 		}
1403 		mutex_exit(&zfsvfs->z_znodes_lock);
1404 	}
1405 
1406 	/*
1407 	 * If we are unmounting, set the unmounted flag and let new VFS ops
1408 	 * unblock.  zfs_inactive will have the unmounted behavior, and all
1409 	 * other VFS ops will fail with EIO.
1410 	 */
1411 	if (unmounting) {
1412 		zfsvfs->z_unmounted = B_TRUE;
1413 		rw_exit(&zfsvfs->z_teardown_inactive_lock);
1414 		ZFS_TEARDOWN_EXIT(zfsvfs, FTAG);
1415 	}
1416 
1417 	/*
1418 	 * z_os will be NULL if there was an error in attempting to reopen
1419 	 * zfsvfs, so just return as the properties had already been
1420 	 *
1421 	 * unregistered and cached data had been evicted before.
1422 	 */
1423 	if (zfsvfs->z_os == NULL)
1424 		return (0);
1425 
1426 	/*
1427 	 * Unregister properties.
1428 	 */
1429 	zfs_unregister_callbacks(zfsvfs);
1430 
1431 	/*
1432 	 * Evict cached data. We must write out any dirty data before
1433 	 * disowning the dataset.
1434 	 */
1435 	objset_t *os = zfsvfs->z_os;
1436 	boolean_t os_dirty = B_FALSE;
1437 	for (int t = 0; t < TXG_SIZE; t++) {
1438 		if (dmu_objset_is_dirty(os, t)) {
1439 			os_dirty = B_TRUE;
1440 			break;
1441 		}
1442 	}
1443 	if (!zfs_is_readonly(zfsvfs) && os_dirty) {
1444 		txg_wait_synced(dmu_objset_pool(zfsvfs->z_os), 0);
1445 	}
1446 	dmu_objset_evict_dbufs(zfsvfs->z_os);
1447 	dsl_dir_t *dd = os->os_dsl_dataset->ds_dir;
1448 	dsl_dir_cancel_waiters(dd);
1449 
1450 	return (0);
1451 }
1452 
1453 #if defined(HAVE_SUPER_SETUP_BDI_NAME)
1454 atomic_long_t zfs_bdi_seq = ATOMIC_LONG_INIT(0);
1455 #endif
1456 
1457 int
1458 zfs_domount(struct super_block *sb, zfs_mnt_t *zm, int silent)
1459 {
1460 	const char *osname = zm->mnt_osname;
1461 	struct inode *root_inode = NULL;
1462 	uint64_t recordsize;
1463 	int error = 0;
1464 	zfsvfs_t *zfsvfs = NULL;
1465 	vfs_t *vfs = NULL;
1466 	int canwrite;
1467 	int dataset_visible_zone;
1468 
1469 	ASSERT(zm);
1470 	ASSERT(osname);
1471 
1472 	dataset_visible_zone = zone_dataset_visible(osname, &canwrite);
1473 
1474 	/*
1475 	 * Refuse to mount a filesystem if we are in a namespace and the
1476 	 * dataset is not visible or writable in that namespace.
1477 	 */
1478 	if (!INGLOBALZONE(curproc) &&
1479 	    (!dataset_visible_zone || !canwrite)) {
1480 		return (SET_ERROR(EPERM));
1481 	}
1482 
1483 	error = zfsvfs_parse_options(zm->mnt_data, &vfs);
1484 	if (error)
1485 		return (error);
1486 
1487 	/*
1488 	 * If a non-writable filesystem is being mounted without the
1489 	 * read-only flag, pretend it was set, as done for snapshots.
1490 	 */
1491 	if (!canwrite)
1492 		vfs->vfs_readonly = true;
1493 
1494 	error = zfsvfs_create(osname, vfs->vfs_readonly, &zfsvfs);
1495 	if (error) {
1496 		zfsvfs_vfs_free(vfs);
1497 		goto out;
1498 	}
1499 
1500 	if ((error = dsl_prop_get_integer(osname, "recordsize",
1501 	    &recordsize, NULL))) {
1502 		zfsvfs_vfs_free(vfs);
1503 		goto out;
1504 	}
1505 
1506 	vfs->vfs_data = zfsvfs;
1507 	zfsvfs->z_vfs = vfs;
1508 	zfsvfs->z_sb = sb;
1509 	sb->s_fs_info = zfsvfs;
1510 	sb->s_magic = ZFS_SUPER_MAGIC;
1511 	sb->s_maxbytes = MAX_LFS_FILESIZE;
1512 	sb->s_time_gran = 1;
1513 	sb->s_blocksize = recordsize;
1514 	sb->s_blocksize_bits = ilog2(recordsize);
1515 
1516 	error = -zpl_bdi_setup(sb, "zfs");
1517 	if (error)
1518 		goto out;
1519 
1520 	sb->s_bdi->ra_pages = 0;
1521 
1522 	/* Set callback operations for the file system. */
1523 	sb->s_op = &zpl_super_operations;
1524 	sb->s_xattr = zpl_xattr_handlers;
1525 	sb->s_export_op = &zpl_export_operations;
1526 
1527 	/* Set features for file system. */
1528 	zfs_set_fuid_feature(zfsvfs);
1529 
1530 	if (dmu_objset_is_snapshot(zfsvfs->z_os)) {
1531 		uint64_t pval;
1532 
1533 		atime_changed_cb(zfsvfs, B_FALSE);
1534 		readonly_changed_cb(zfsvfs, B_TRUE);
1535 		if ((error = dsl_prop_get_integer(osname,
1536 		    "xattr", &pval, NULL)))
1537 			goto out;
1538 		xattr_changed_cb(zfsvfs, pval);
1539 		if ((error = dsl_prop_get_integer(osname,
1540 		    "acltype", &pval, NULL)))
1541 			goto out;
1542 		acltype_changed_cb(zfsvfs, pval);
1543 		zfsvfs->z_issnap = B_TRUE;
1544 		zfsvfs->z_os->os_sync = ZFS_SYNC_DISABLED;
1545 		zfsvfs->z_snap_defer_time = jiffies;
1546 
1547 		mutex_enter(&zfsvfs->z_os->os_user_ptr_lock);
1548 		dmu_objset_set_user(zfsvfs->z_os, zfsvfs);
1549 		mutex_exit(&zfsvfs->z_os->os_user_ptr_lock);
1550 	} else {
1551 		if ((error = zfsvfs_setup(zfsvfs, B_TRUE)))
1552 			goto out;
1553 	}
1554 
1555 	/* Allocate a root inode for the filesystem. */
1556 	error = zfs_root(zfsvfs, &root_inode);
1557 	if (error) {
1558 		(void) zfs_umount(sb);
1559 		zfsvfs = NULL; /* avoid double-free; first in zfs_umount */
1560 		goto out;
1561 	}
1562 
1563 	/* Allocate a root dentry for the filesystem */
1564 	sb->s_root = d_make_root(root_inode);
1565 	if (sb->s_root == NULL) {
1566 		(void) zfs_umount(sb);
1567 		zfsvfs = NULL; /* avoid double-free; first in zfs_umount */
1568 		error = SET_ERROR(ENOMEM);
1569 		goto out;
1570 	}
1571 
1572 	if (!zfsvfs->z_issnap)
1573 		zfsctl_create(zfsvfs);
1574 
1575 	zfsvfs->z_arc_prune = arc_add_prune_callback(zpl_prune_sb, sb);
1576 out:
1577 	if (error) {
1578 		if (zfsvfs != NULL) {
1579 			dmu_objset_disown(zfsvfs->z_os, B_TRUE, zfsvfs);
1580 			zfsvfs_free(zfsvfs);
1581 		}
1582 		/*
1583 		 * make sure we don't have dangling sb->s_fs_info which
1584 		 * zfs_preumount will use.
1585 		 */
1586 		sb->s_fs_info = NULL;
1587 	}
1588 
1589 	return (error);
1590 }
1591 
1592 /*
1593  * Called when an unmount is requested and certain sanity checks have
1594  * already passed.  At this point no dentries or inodes have been reclaimed
1595  * from their respective caches.  We drop the extra reference on the .zfs
1596  * control directory to allow everything to be reclaimed.  All snapshots
1597  * must already have been unmounted to reach this point.
1598  */
1599 void
1600 zfs_preumount(struct super_block *sb)
1601 {
1602 	zfsvfs_t *zfsvfs = sb->s_fs_info;
1603 
1604 	/* zfsvfs is NULL when zfs_domount fails during mount */
1605 	if (zfsvfs) {
1606 		zfs_unlinked_drain_stop_wait(zfsvfs);
1607 		zfsctl_destroy(sb->s_fs_info);
1608 		/*
1609 		 * Wait for zrele_async before entering evict_inodes in
1610 		 * generic_shutdown_super. The reason we must finish before
1611 		 * evict_inodes is when lazytime is on, or when zfs_purgedir
1612 		 * calls zfs_zget, zrele would bump i_count from 0 to 1. This
1613 		 * would race with the i_count check in evict_inodes. This means
1614 		 * it could destroy the inode while we are still using it.
1615 		 *
1616 		 * We wait for two passes. xattr directories in the first pass
1617 		 * may add xattr entries in zfs_purgedir, so in the second pass
1618 		 * we wait for them. We don't use taskq_wait here because it is
1619 		 * a pool wide taskq. Other mounted filesystems can constantly
1620 		 * do zrele_async and there's no guarantee when taskq will be
1621 		 * empty.
1622 		 */
1623 		taskq_wait_outstanding(dsl_pool_zrele_taskq(
1624 		    dmu_objset_pool(zfsvfs->z_os)), 0);
1625 		taskq_wait_outstanding(dsl_pool_zrele_taskq(
1626 		    dmu_objset_pool(zfsvfs->z_os)), 0);
1627 	}
1628 }
1629 
1630 /*
1631  * Called once all other unmount released tear down has occurred.
1632  * It is our responsibility to release any remaining infrastructure.
1633  */
1634 int
1635 zfs_umount(struct super_block *sb)
1636 {
1637 	zfsvfs_t *zfsvfs = sb->s_fs_info;
1638 	objset_t *os;
1639 
1640 	if (zfsvfs->z_arc_prune != NULL)
1641 		arc_remove_prune_callback(zfsvfs->z_arc_prune);
1642 	VERIFY(zfsvfs_teardown(zfsvfs, B_TRUE) == 0);
1643 	os = zfsvfs->z_os;
1644 	zpl_bdi_destroy(sb);
1645 
1646 	/*
1647 	 * z_os will be NULL if there was an error in
1648 	 * attempting to reopen zfsvfs.
1649 	 */
1650 	if (os != NULL) {
1651 		/*
1652 		 * Unset the objset user_ptr.
1653 		 */
1654 		mutex_enter(&os->os_user_ptr_lock);
1655 		dmu_objset_set_user(os, NULL);
1656 		mutex_exit(&os->os_user_ptr_lock);
1657 
1658 		/*
1659 		 * Finally release the objset
1660 		 */
1661 		dmu_objset_disown(os, B_TRUE, zfsvfs);
1662 	}
1663 
1664 	zfsvfs_free(zfsvfs);
1665 	return (0);
1666 }
1667 
1668 int
1669 zfs_remount(struct super_block *sb, int *flags, zfs_mnt_t *zm)
1670 {
1671 	zfsvfs_t *zfsvfs = sb->s_fs_info;
1672 	vfs_t *vfsp;
1673 	boolean_t issnap = dmu_objset_is_snapshot(zfsvfs->z_os);
1674 	int error;
1675 
1676 	if ((issnap || !spa_writeable(dmu_objset_spa(zfsvfs->z_os))) &&
1677 	    !(*flags & SB_RDONLY)) {
1678 		*flags |= SB_RDONLY;
1679 		return (EROFS);
1680 	}
1681 
1682 	error = zfsvfs_parse_options(zm->mnt_data, &vfsp);
1683 	if (error)
1684 		return (error);
1685 
1686 	if (!zfs_is_readonly(zfsvfs) && (*flags & SB_RDONLY))
1687 		txg_wait_synced(dmu_objset_pool(zfsvfs->z_os), 0);
1688 
1689 	zfs_unregister_callbacks(zfsvfs);
1690 	zfsvfs_vfs_free(zfsvfs->z_vfs);
1691 
1692 	vfsp->vfs_data = zfsvfs;
1693 	zfsvfs->z_vfs = vfsp;
1694 	if (!issnap)
1695 		(void) zfs_register_callbacks(vfsp);
1696 
1697 	return (error);
1698 }
1699 
1700 int
1701 zfs_vget(struct super_block *sb, struct inode **ipp, fid_t *fidp)
1702 {
1703 	zfsvfs_t	*zfsvfs = sb->s_fs_info;
1704 	znode_t		*zp;
1705 	uint64_t	object = 0;
1706 	uint64_t	fid_gen = 0;
1707 	uint64_t	gen_mask;
1708 	uint64_t	zp_gen;
1709 	int		i, err;
1710 
1711 	*ipp = NULL;
1712 
1713 	if (fidp->fid_len == SHORT_FID_LEN || fidp->fid_len == LONG_FID_LEN) {
1714 		zfid_short_t	*zfid = (zfid_short_t *)fidp;
1715 
1716 		for (i = 0; i < sizeof (zfid->zf_object); i++)
1717 			object |= ((uint64_t)zfid->zf_object[i]) << (8 * i);
1718 
1719 		for (i = 0; i < sizeof (zfid->zf_gen); i++)
1720 			fid_gen |= ((uint64_t)zfid->zf_gen[i]) << (8 * i);
1721 	} else {
1722 		return (SET_ERROR(EINVAL));
1723 	}
1724 
1725 	/* LONG_FID_LEN means snapdirs */
1726 	if (fidp->fid_len == LONG_FID_LEN) {
1727 		zfid_long_t	*zlfid = (zfid_long_t *)fidp;
1728 		uint64_t	objsetid = 0;
1729 		uint64_t	setgen = 0;
1730 
1731 		for (i = 0; i < sizeof (zlfid->zf_setid); i++)
1732 			objsetid |= ((uint64_t)zlfid->zf_setid[i]) << (8 * i);
1733 
1734 		for (i = 0; i < sizeof (zlfid->zf_setgen); i++)
1735 			setgen |= ((uint64_t)zlfid->zf_setgen[i]) << (8 * i);
1736 
1737 		if (objsetid != ZFSCTL_INO_SNAPDIRS - object) {
1738 			dprintf("snapdir fid: objsetid (%llu) != "
1739 			    "ZFSCTL_INO_SNAPDIRS (%llu) - object (%llu)\n",
1740 			    objsetid, ZFSCTL_INO_SNAPDIRS, object);
1741 
1742 			return (SET_ERROR(EINVAL));
1743 		}
1744 
1745 		if (fid_gen > 1 || setgen != 0) {
1746 			dprintf("snapdir fid: fid_gen (%llu) and setgen "
1747 			    "(%llu)\n", fid_gen, setgen);
1748 			return (SET_ERROR(EINVAL));
1749 		}
1750 
1751 		return (zfsctl_snapdir_vget(sb, objsetid, fid_gen, ipp));
1752 	}
1753 
1754 	if ((err = zfs_enter(zfsvfs, FTAG)) != 0)
1755 		return (err);
1756 	/* A zero fid_gen means we are in the .zfs control directories */
1757 	if (fid_gen == 0 &&
1758 	    (object == ZFSCTL_INO_ROOT || object == ZFSCTL_INO_SNAPDIR)) {
1759 		*ipp = zfsvfs->z_ctldir;
1760 		ASSERT(*ipp != NULL);
1761 		if (object == ZFSCTL_INO_SNAPDIR) {
1762 			VERIFY(zfsctl_root_lookup(*ipp, "snapshot", ipp,
1763 			    0, kcred, NULL, NULL) == 0);
1764 		} else {
1765 			/*
1766 			 * Must have an existing ref, so igrab()
1767 			 * cannot return NULL
1768 			 */
1769 			VERIFY3P(igrab(*ipp), !=, NULL);
1770 		}
1771 		zfs_exit(zfsvfs, FTAG);
1772 		return (0);
1773 	}
1774 
1775 	gen_mask = -1ULL >> (64 - 8 * i);
1776 
1777 	dprintf("getting %llu [%llu mask %llx]\n", object, fid_gen, gen_mask);
1778 	if ((err = zfs_zget(zfsvfs, object, &zp))) {
1779 		zfs_exit(zfsvfs, FTAG);
1780 		return (err);
1781 	}
1782 
1783 	/* Don't export xattr stuff */
1784 	if (zp->z_pflags & ZFS_XATTR) {
1785 		zrele(zp);
1786 		zfs_exit(zfsvfs, FTAG);
1787 		return (SET_ERROR(ENOENT));
1788 	}
1789 
1790 	(void) sa_lookup(zp->z_sa_hdl, SA_ZPL_GEN(zfsvfs), &zp_gen,
1791 	    sizeof (uint64_t));
1792 	zp_gen = zp_gen & gen_mask;
1793 	if (zp_gen == 0)
1794 		zp_gen = 1;
1795 	if ((fid_gen == 0) && (zfsvfs->z_root == object))
1796 		fid_gen = zp_gen;
1797 	if (zp->z_unlinked || zp_gen != fid_gen) {
1798 		dprintf("znode gen (%llu) != fid gen (%llu)\n", zp_gen,
1799 		    fid_gen);
1800 		zrele(zp);
1801 		zfs_exit(zfsvfs, FTAG);
1802 		return (SET_ERROR(ENOENT));
1803 	}
1804 
1805 	*ipp = ZTOI(zp);
1806 	if (*ipp)
1807 		zfs_znode_update_vfs(ITOZ(*ipp));
1808 
1809 	zfs_exit(zfsvfs, FTAG);
1810 	return (0);
1811 }
1812 
1813 /*
1814  * Block out VFS ops and close zfsvfs_t
1815  *
1816  * Note, if successful, then we return with the 'z_teardown_lock' and
1817  * 'z_teardown_inactive_lock' write held.  We leave ownership of the underlying
1818  * dataset and objset intact so that they can be atomically handed off during
1819  * a subsequent rollback or recv operation and the resume thereafter.
1820  */
1821 int
1822 zfs_suspend_fs(zfsvfs_t *zfsvfs)
1823 {
1824 	int error;
1825 
1826 	if ((error = zfsvfs_teardown(zfsvfs, B_FALSE)) != 0)
1827 		return (error);
1828 
1829 	return (0);
1830 }
1831 
1832 /*
1833  * Rebuild SA and release VOPs.  Note that ownership of the underlying dataset
1834  * is an invariant across any of the operations that can be performed while the
1835  * filesystem was suspended.  Whether it succeeded or failed, the preconditions
1836  * are the same: the relevant objset and associated dataset are owned by
1837  * zfsvfs, held, and long held on entry.
1838  */
1839 int
1840 zfs_resume_fs(zfsvfs_t *zfsvfs, dsl_dataset_t *ds)
1841 {
1842 	int err, err2;
1843 	znode_t *zp;
1844 
1845 	ASSERT(ZFS_TEARDOWN_WRITE_HELD(zfsvfs));
1846 	ASSERT(RW_WRITE_HELD(&zfsvfs->z_teardown_inactive_lock));
1847 
1848 	/*
1849 	 * We already own this, so just update the objset_t, as the one we
1850 	 * had before may have been evicted.
1851 	 */
1852 	objset_t *os;
1853 	VERIFY3P(ds->ds_owner, ==, zfsvfs);
1854 	VERIFY(dsl_dataset_long_held(ds));
1855 	dsl_pool_t *dp = spa_get_dsl(dsl_dataset_get_spa(ds));
1856 	dsl_pool_config_enter(dp, FTAG);
1857 	VERIFY0(dmu_objset_from_ds(ds, &os));
1858 	dsl_pool_config_exit(dp, FTAG);
1859 
1860 	err = zfsvfs_init(zfsvfs, os);
1861 	if (err != 0)
1862 		goto bail;
1863 
1864 	ds->ds_dir->dd_activity_cancelled = B_FALSE;
1865 	VERIFY(zfsvfs_setup(zfsvfs, B_FALSE) == 0);
1866 
1867 	zfs_set_fuid_feature(zfsvfs);
1868 	zfsvfs->z_rollback_time = jiffies;
1869 
1870 	/*
1871 	 * Attempt to re-establish all the active inodes with their
1872 	 * dbufs.  If a zfs_rezget() fails, then we unhash the inode
1873 	 * and mark it stale.  This prevents a collision if a new
1874 	 * inode/object is created which must use the same inode
1875 	 * number.  The stale inode will be be released when the
1876 	 * VFS prunes the dentry holding the remaining references
1877 	 * on the stale inode.
1878 	 */
1879 	mutex_enter(&zfsvfs->z_znodes_lock);
1880 	for (zp = list_head(&zfsvfs->z_all_znodes); zp;
1881 	    zp = list_next(&zfsvfs->z_all_znodes, zp)) {
1882 		err2 = zfs_rezget(zp);
1883 		if (err2) {
1884 			zpl_d_drop_aliases(ZTOI(zp));
1885 			remove_inode_hash(ZTOI(zp));
1886 		}
1887 
1888 		/* see comment in zfs_suspend_fs() */
1889 		if (zp->z_suspended) {
1890 			zfs_zrele_async(zp);
1891 			zp->z_suspended = B_FALSE;
1892 		}
1893 	}
1894 	mutex_exit(&zfsvfs->z_znodes_lock);
1895 
1896 	if (!zfs_is_readonly(zfsvfs) && !zfsvfs->z_unmounted) {
1897 		/*
1898 		 * zfs_suspend_fs() could have interrupted freeing
1899 		 * of dnodes. We need to restart this freeing so
1900 		 * that we don't "leak" the space.
1901 		 */
1902 		zfs_unlinked_drain(zfsvfs);
1903 	}
1904 
1905 	/*
1906 	 * Most of the time zfs_suspend_fs is used for changing the contents
1907 	 * of the underlying dataset. ZFS rollback and receive operations
1908 	 * might create files for which negative dentries are present in
1909 	 * the cache. Since walking the dcache would require a lot of GPL-only
1910 	 * code duplication, it's much easier on these rather rare occasions
1911 	 * just to flush the whole dcache for the given dataset/filesystem.
1912 	 */
1913 	shrink_dcache_sb(zfsvfs->z_sb);
1914 
1915 bail:
1916 	if (err != 0)
1917 		zfsvfs->z_unmounted = B_TRUE;
1918 
1919 	/* release the VFS ops */
1920 	rw_exit(&zfsvfs->z_teardown_inactive_lock);
1921 	ZFS_TEARDOWN_EXIT(zfsvfs, FTAG);
1922 
1923 	if (err != 0) {
1924 		/*
1925 		 * Since we couldn't setup the sa framework, try to force
1926 		 * unmount this file system.
1927 		 */
1928 		if (zfsvfs->z_os)
1929 			(void) zfs_umount(zfsvfs->z_sb);
1930 	}
1931 	return (err);
1932 }
1933 
1934 /*
1935  * Release VOPs and unmount a suspended filesystem.
1936  */
1937 int
1938 zfs_end_fs(zfsvfs_t *zfsvfs, dsl_dataset_t *ds)
1939 {
1940 	ASSERT(ZFS_TEARDOWN_WRITE_HELD(zfsvfs));
1941 	ASSERT(RW_WRITE_HELD(&zfsvfs->z_teardown_inactive_lock));
1942 
1943 	/*
1944 	 * We already own this, so just hold and rele it to update the
1945 	 * objset_t, as the one we had before may have been evicted.
1946 	 */
1947 	objset_t *os;
1948 	VERIFY3P(ds->ds_owner, ==, zfsvfs);
1949 	VERIFY(dsl_dataset_long_held(ds));
1950 	dsl_pool_t *dp = spa_get_dsl(dsl_dataset_get_spa(ds));
1951 	dsl_pool_config_enter(dp, FTAG);
1952 	VERIFY0(dmu_objset_from_ds(ds, &os));
1953 	dsl_pool_config_exit(dp, FTAG);
1954 	zfsvfs->z_os = os;
1955 
1956 	/* release the VOPs */
1957 	rw_exit(&zfsvfs->z_teardown_inactive_lock);
1958 	ZFS_TEARDOWN_EXIT(zfsvfs, FTAG);
1959 
1960 	/*
1961 	 * Try to force unmount this file system.
1962 	 */
1963 	(void) zfs_umount(zfsvfs->z_sb);
1964 	zfsvfs->z_unmounted = B_TRUE;
1965 	return (0);
1966 }
1967 
1968 /*
1969  * Automounted snapshots rely on periodic revalidation
1970  * to defer snapshots from being automatically unmounted.
1971  */
1972 
1973 inline void
1974 zfs_exit_fs(zfsvfs_t *zfsvfs)
1975 {
1976 	if (!zfsvfs->z_issnap)
1977 		return;
1978 
1979 	if (time_after(jiffies, zfsvfs->z_snap_defer_time +
1980 	    MAX(zfs_expire_snapshot * HZ / 2, HZ))) {
1981 		zfsvfs->z_snap_defer_time = jiffies;
1982 		zfsctl_snapshot_unmount_delay(zfsvfs->z_os->os_spa,
1983 		    dmu_objset_id(zfsvfs->z_os),
1984 		    zfs_expire_snapshot);
1985 	}
1986 }
1987 
1988 int
1989 zfs_set_version(zfsvfs_t *zfsvfs, uint64_t newvers)
1990 {
1991 	int error;
1992 	objset_t *os = zfsvfs->z_os;
1993 	dmu_tx_t *tx;
1994 
1995 	if (newvers < ZPL_VERSION_INITIAL || newvers > ZPL_VERSION)
1996 		return (SET_ERROR(EINVAL));
1997 
1998 	if (newvers < zfsvfs->z_version)
1999 		return (SET_ERROR(EINVAL));
2000 
2001 	if (zfs_spa_version_map(newvers) >
2002 	    spa_version(dmu_objset_spa(zfsvfs->z_os)))
2003 		return (SET_ERROR(ENOTSUP));
2004 
2005 	tx = dmu_tx_create(os);
2006 	dmu_tx_hold_zap(tx, MASTER_NODE_OBJ, B_FALSE, ZPL_VERSION_STR);
2007 	if (newvers >= ZPL_VERSION_SA && !zfsvfs->z_use_sa) {
2008 		dmu_tx_hold_zap(tx, MASTER_NODE_OBJ, B_TRUE,
2009 		    ZFS_SA_ATTRS);
2010 		dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, FALSE, NULL);
2011 	}
2012 	error = dmu_tx_assign(tx, TXG_WAIT);
2013 	if (error) {
2014 		dmu_tx_abort(tx);
2015 		return (error);
2016 	}
2017 
2018 	error = zap_update(os, MASTER_NODE_OBJ, ZPL_VERSION_STR,
2019 	    8, 1, &newvers, tx);
2020 
2021 	if (error) {
2022 		dmu_tx_commit(tx);
2023 		return (error);
2024 	}
2025 
2026 	if (newvers >= ZPL_VERSION_SA && !zfsvfs->z_use_sa) {
2027 		uint64_t sa_obj;
2028 
2029 		ASSERT3U(spa_version(dmu_objset_spa(zfsvfs->z_os)), >=,
2030 		    SPA_VERSION_SA);
2031 		sa_obj = zap_create(os, DMU_OT_SA_MASTER_NODE,
2032 		    DMU_OT_NONE, 0, tx);
2033 
2034 		error = zap_add(os, MASTER_NODE_OBJ,
2035 		    ZFS_SA_ATTRS, 8, 1, &sa_obj, tx);
2036 		ASSERT0(error);
2037 
2038 		VERIFY(0 == sa_set_sa_object(os, sa_obj));
2039 		sa_register_update_callback(os, zfs_sa_upgrade);
2040 	}
2041 
2042 	spa_history_log_internal_ds(dmu_objset_ds(os), "upgrade", tx,
2043 	    "from %llu to %llu", zfsvfs->z_version, newvers);
2044 
2045 	dmu_tx_commit(tx);
2046 
2047 	zfsvfs->z_version = newvers;
2048 	os->os_version = newvers;
2049 
2050 	zfs_set_fuid_feature(zfsvfs);
2051 
2052 	return (0);
2053 }
2054 
2055 /*
2056  * Return true if the corresponding vfs's unmounted flag is set.
2057  * Otherwise return false.
2058  * If this function returns true we know VFS unmount has been initiated.
2059  */
2060 boolean_t
2061 zfs_get_vfs_flag_unmounted(objset_t *os)
2062 {
2063 	zfsvfs_t *zfvp;
2064 	boolean_t unmounted = B_FALSE;
2065 
2066 	ASSERT(dmu_objset_type(os) == DMU_OST_ZFS);
2067 
2068 	mutex_enter(&os->os_user_ptr_lock);
2069 	zfvp = dmu_objset_get_user(os);
2070 	if (zfvp != NULL && zfvp->z_unmounted)
2071 		unmounted = B_TRUE;
2072 	mutex_exit(&os->os_user_ptr_lock);
2073 
2074 	return (unmounted);
2075 }
2076 
2077 void
2078 zfsvfs_update_fromname(const char *oldname, const char *newname)
2079 {
2080 	/*
2081 	 * We don't need to do anything here, the devname is always current by
2082 	 * virtue of zfsvfs->z_sb->s_op->show_devname.
2083 	 */
2084 	(void) oldname, (void) newname;
2085 }
2086 
2087 void
2088 zfs_init(void)
2089 {
2090 	zfsctl_init();
2091 	zfs_znode_init();
2092 	dmu_objset_register_type(DMU_OST_ZFS, zpl_get_file_info);
2093 	register_filesystem(&zpl_fs_type);
2094 }
2095 
2096 void
2097 zfs_fini(void)
2098 {
2099 	/*
2100 	 * we don't use outstanding because zpl_posix_acl_free might add more.
2101 	 */
2102 	taskq_wait(system_delay_taskq);
2103 	taskq_wait(system_taskq);
2104 	unregister_filesystem(&zpl_fs_type);
2105 	zfs_znode_fini();
2106 	zfsctl_fini();
2107 }
2108 
2109 #if defined(_KERNEL)
2110 EXPORT_SYMBOL(zfs_suspend_fs);
2111 EXPORT_SYMBOL(zfs_resume_fs);
2112 EXPORT_SYMBOL(zfs_set_version);
2113 EXPORT_SYMBOL(zfsvfs_create);
2114 EXPORT_SYMBOL(zfsvfs_free);
2115 EXPORT_SYMBOL(zfs_is_readonly);
2116 EXPORT_SYMBOL(zfs_domount);
2117 EXPORT_SYMBOL(zfs_preumount);
2118 EXPORT_SYMBOL(zfs_umount);
2119 EXPORT_SYMBOL(zfs_remount);
2120 EXPORT_SYMBOL(zfs_statvfs);
2121 EXPORT_SYMBOL(zfs_vget);
2122 EXPORT_SYMBOL(zfs_prune);
2123 #endif
2124