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) 2011 Lawrence Livermore National Security, LLC.
23  * Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
24  * LLNL-CODE-403049.
25  * Rewritten for Linux by:
26  *   Rohan Puri <rohan.puri15@gmail.com>
27  *   Brian Behlendorf <behlendorf1@llnl.gov>
28  */
29 
30 #include <sys/zfs_znode.h>
31 #include <sys/zfs_vfsops.h>
32 #include <sys/zfs_vnops.h>
33 #include <sys/zfs_ctldir.h>
34 #include <sys/zpl.h>
35 #include <sys/dmu.h>
36 #include <sys/dsl_dataset.h>
37 #include <sys/zap.h>
38 
39 /*
40  * Common open routine.  Disallow any write access.
41  */
42 static int
43 zpl_common_open(struct inode *ip, struct file *filp)
44 {
45 	if (blk_mode_is_open_write(filp->f_mode))
46 		return (-EACCES);
47 
48 	return (generic_file_open(ip, filp));
49 }
50 
51 /*
52  * Get root directory contents.
53  */
54 static int
55 zpl_root_iterate(struct file *filp, zpl_dir_context_t *ctx)
56 {
57 	zfsvfs_t *zfsvfs = ITOZSB(file_inode(filp));
58 	int error = 0;
59 
60 	if ((error = zpl_enter(zfsvfs, FTAG)) != 0)
61 		return (error);
62 
63 	if (!zpl_dir_emit_dots(filp, ctx))
64 		goto out;
65 
66 	if (ctx->pos == 2) {
67 		if (!zpl_dir_emit(ctx, ZFS_SNAPDIR_NAME,
68 		    strlen(ZFS_SNAPDIR_NAME), ZFSCTL_INO_SNAPDIR, DT_DIR))
69 			goto out;
70 
71 		ctx->pos++;
72 	}
73 
74 	if (ctx->pos == 3) {
75 		if (!zpl_dir_emit(ctx, ZFS_SHAREDIR_NAME,
76 		    strlen(ZFS_SHAREDIR_NAME), ZFSCTL_INO_SHARES, DT_DIR))
77 			goto out;
78 
79 		ctx->pos++;
80 	}
81 out:
82 	zpl_exit(zfsvfs, FTAG);
83 
84 	return (error);
85 }
86 
87 #if !defined(HAVE_VFS_ITERATE) && !defined(HAVE_VFS_ITERATE_SHARED)
88 static int
89 zpl_root_readdir(struct file *filp, void *dirent, filldir_t filldir)
90 {
91 	zpl_dir_context_t ctx =
92 	    ZPL_DIR_CONTEXT_INIT(dirent, filldir, filp->f_pos);
93 	int error;
94 
95 	error = zpl_root_iterate(filp, &ctx);
96 	filp->f_pos = ctx.pos;
97 
98 	return (error);
99 }
100 #endif /* !HAVE_VFS_ITERATE && !HAVE_VFS_ITERATE_SHARED */
101 
102 /*
103  * Get root directory attributes.
104  */
105 static int
106 #ifdef HAVE_IDMAP_IOPS_GETATTR
107 zpl_root_getattr_impl(struct mnt_idmap *user_ns,
108     const struct path *path, struct kstat *stat, u32 request_mask,
109     unsigned int query_flags)
110 #elif defined(HAVE_USERNS_IOPS_GETATTR)
111 zpl_root_getattr_impl(struct user_namespace *user_ns,
112     const struct path *path, struct kstat *stat, u32 request_mask,
113     unsigned int query_flags)
114 #else
115 zpl_root_getattr_impl(const struct path *path, struct kstat *stat,
116     u32 request_mask, unsigned int query_flags)
117 #endif
118 {
119 	(void) request_mask, (void) query_flags;
120 	struct inode *ip = path->dentry->d_inode;
121 
122 #if (defined(HAVE_USERNS_IOPS_GETATTR) || defined(HAVE_IDMAP_IOPS_GETATTR))
123 #ifdef HAVE_GENERIC_FILLATTR_USERNS
124 	generic_fillattr(user_ns, ip, stat);
125 #elif defined(HAVE_GENERIC_FILLATTR_IDMAP)
126 	generic_fillattr(user_ns, ip, stat);
127 #elif defined(HAVE_GENERIC_FILLATTR_IDMAP_REQMASK)
128 	generic_fillattr(user_ns, request_mask, ip, stat);
129 #else
130 	(void) user_ns;
131 #endif
132 #else
133 	generic_fillattr(ip, stat);
134 #endif
135 	stat->atime = current_time(ip);
136 
137 	return (0);
138 }
139 ZPL_GETATTR_WRAPPER(zpl_root_getattr);
140 
141 static struct dentry *
142 zpl_root_lookup(struct inode *dip, struct dentry *dentry, unsigned int flags)
143 {
144 	cred_t *cr = CRED();
145 	struct inode *ip;
146 	int error;
147 
148 	crhold(cr);
149 	error = -zfsctl_root_lookup(dip, dname(dentry), &ip, 0, cr, NULL, NULL);
150 	ASSERT3S(error, <=, 0);
151 	crfree(cr);
152 
153 	if (error) {
154 		if (error == -ENOENT)
155 			return (d_splice_alias(NULL, dentry));
156 		else
157 			return (ERR_PTR(error));
158 	}
159 
160 	return (d_splice_alias(ip, dentry));
161 }
162 
163 /*
164  * The '.zfs' control directory file and inode operations.
165  */
166 const struct file_operations zpl_fops_root = {
167 	.open		= zpl_common_open,
168 	.llseek		= generic_file_llseek,
169 	.read		= generic_read_dir,
170 #ifdef HAVE_VFS_ITERATE_SHARED
171 	.iterate_shared	= zpl_root_iterate,
172 #elif defined(HAVE_VFS_ITERATE)
173 	.iterate	= zpl_root_iterate,
174 #else
175 	.readdir	= zpl_root_readdir,
176 #endif
177 };
178 
179 const struct inode_operations zpl_ops_root = {
180 	.lookup		= zpl_root_lookup,
181 	.getattr	= zpl_root_getattr,
182 };
183 
184 static struct vfsmount *
185 zpl_snapdir_automount(struct path *path)
186 {
187 	int error;
188 
189 	error = -zfsctl_snapshot_mount(path, 0);
190 	if (error)
191 		return (ERR_PTR(error));
192 
193 	/*
194 	 * Rather than returning the new vfsmount for the snapshot we must
195 	 * return NULL to indicate a mount collision.  This is done because
196 	 * the user space mount calls do_add_mount() which adds the vfsmount
197 	 * to the name space.  If we returned the new mount here it would be
198 	 * added again to the vfsmount list resulting in list corruption.
199 	 */
200 	return (NULL);
201 }
202 
203 /*
204  * Negative dentries must always be revalidated so newly created snapshots
205  * can be detected and automounted.  Normal dentries should be kept because
206  * as of the 3.18 kernel revaliding the mountpoint dentry will result in
207  * the snapshot being immediately unmounted.
208  */
209 static int
210 #ifdef HAVE_D_REVALIDATE_NAMEIDATA
211 zpl_snapdir_revalidate(struct dentry *dentry, struct nameidata *i)
212 #else
213 zpl_snapdir_revalidate(struct dentry *dentry, unsigned int flags)
214 #endif
215 {
216 	return (!!dentry->d_inode);
217 }
218 
219 static dentry_operations_t zpl_dops_snapdirs = {
220 /*
221  * Auto mounting of snapshots is only supported for 2.6.37 and
222  * newer kernels.  Prior to this kernel the ops->follow_link()
223  * callback was used as a hack to trigger the mount.  The
224  * resulting vfsmount was then explicitly grafted in to the
225  * name space.  While it might be possible to add compatibility
226  * code to accomplish this it would require considerable care.
227  */
228 	.d_automount	= zpl_snapdir_automount,
229 	.d_revalidate	= zpl_snapdir_revalidate,
230 };
231 
232 static struct dentry *
233 zpl_snapdir_lookup(struct inode *dip, struct dentry *dentry,
234     unsigned int flags)
235 {
236 	fstrans_cookie_t cookie;
237 	cred_t *cr = CRED();
238 	struct inode *ip = NULL;
239 	int error;
240 
241 	crhold(cr);
242 	cookie = spl_fstrans_mark();
243 	error = -zfsctl_snapdir_lookup(dip, dname(dentry), &ip,
244 	    0, cr, NULL, NULL);
245 	ASSERT3S(error, <=, 0);
246 	spl_fstrans_unmark(cookie);
247 	crfree(cr);
248 
249 	if (error && error != -ENOENT)
250 		return (ERR_PTR(error));
251 
252 	ASSERT(error == 0 || ip == NULL);
253 	d_clear_d_op(dentry);
254 	d_set_d_op(dentry, &zpl_dops_snapdirs);
255 	dentry->d_flags |= DCACHE_NEED_AUTOMOUNT;
256 
257 	return (d_splice_alias(ip, dentry));
258 }
259 
260 static int
261 zpl_snapdir_iterate(struct file *filp, zpl_dir_context_t *ctx)
262 {
263 	zfsvfs_t *zfsvfs = ITOZSB(file_inode(filp));
264 	fstrans_cookie_t cookie;
265 	char snapname[MAXNAMELEN];
266 	boolean_t case_conflict;
267 	uint64_t id, pos;
268 	int error = 0;
269 
270 	if ((error = zpl_enter(zfsvfs, FTAG)) != 0)
271 		return (error);
272 	cookie = spl_fstrans_mark();
273 
274 	if (!zpl_dir_emit_dots(filp, ctx))
275 		goto out;
276 
277 	/* Start the position at 0 if it already emitted . and .. */
278 	pos = (ctx->pos == 2 ? 0 : ctx->pos);
279 	while (error == 0) {
280 		dsl_pool_config_enter(dmu_objset_pool(zfsvfs->z_os), FTAG);
281 		error = -dmu_snapshot_list_next(zfsvfs->z_os, MAXNAMELEN,
282 		    snapname, &id, &pos, &case_conflict);
283 		dsl_pool_config_exit(dmu_objset_pool(zfsvfs->z_os), FTAG);
284 		if (error)
285 			goto out;
286 
287 		if (!zpl_dir_emit(ctx, snapname, strlen(snapname),
288 		    ZFSCTL_INO_SHARES - id, DT_DIR))
289 			goto out;
290 
291 		ctx->pos = pos;
292 	}
293 out:
294 	spl_fstrans_unmark(cookie);
295 	zpl_exit(zfsvfs, FTAG);
296 
297 	if (error == -ENOENT)
298 		return (0);
299 
300 	return (error);
301 }
302 
303 #if !defined(HAVE_VFS_ITERATE) && !defined(HAVE_VFS_ITERATE_SHARED)
304 static int
305 zpl_snapdir_readdir(struct file *filp, void *dirent, filldir_t filldir)
306 {
307 	zpl_dir_context_t ctx =
308 	    ZPL_DIR_CONTEXT_INIT(dirent, filldir, filp->f_pos);
309 	int error;
310 
311 	error = zpl_snapdir_iterate(filp, &ctx);
312 	filp->f_pos = ctx.pos;
313 
314 	return (error);
315 }
316 #endif /* !HAVE_VFS_ITERATE && !HAVE_VFS_ITERATE_SHARED */
317 
318 static int
319 #ifdef HAVE_IOPS_RENAME_USERNS
320 zpl_snapdir_rename2(struct user_namespace *user_ns, struct inode *sdip,
321     struct dentry *sdentry, struct inode *tdip, struct dentry *tdentry,
322     unsigned int flags)
323 #elif defined(HAVE_IOPS_RENAME_IDMAP)
324 zpl_snapdir_rename2(struct mnt_idmap *user_ns, struct inode *sdip,
325     struct dentry *sdentry, struct inode *tdip, struct dentry *tdentry,
326     unsigned int flags)
327 #else
328 zpl_snapdir_rename2(struct inode *sdip, struct dentry *sdentry,
329     struct inode *tdip, struct dentry *tdentry, unsigned int flags)
330 #endif
331 {
332 	cred_t *cr = CRED();
333 	int error;
334 
335 	/* We probably don't want to support renameat2(2) in ctldir */
336 	if (flags)
337 		return (-EINVAL);
338 
339 	crhold(cr);
340 	error = -zfsctl_snapdir_rename(sdip, dname(sdentry),
341 	    tdip, dname(tdentry), cr, 0);
342 	ASSERT3S(error, <=, 0);
343 	crfree(cr);
344 
345 	return (error);
346 }
347 
348 #if (!defined(HAVE_RENAME_WANTS_FLAGS) && \
349 	!defined(HAVE_IOPS_RENAME_USERNS) && \
350 	!defined(HAVE_IOPS_RENAME_IDMAP))
351 static int
352 zpl_snapdir_rename(struct inode *sdip, struct dentry *sdentry,
353     struct inode *tdip, struct dentry *tdentry)
354 {
355 	return (zpl_snapdir_rename2(sdip, sdentry, tdip, tdentry, 0));
356 }
357 #endif
358 
359 static int
360 zpl_snapdir_rmdir(struct inode *dip, struct dentry *dentry)
361 {
362 	cred_t *cr = CRED();
363 	int error;
364 
365 	crhold(cr);
366 	error = -zfsctl_snapdir_remove(dip, dname(dentry), cr, 0);
367 	ASSERT3S(error, <=, 0);
368 	crfree(cr);
369 
370 	return (error);
371 }
372 
373 static int
374 #ifdef HAVE_IOPS_MKDIR_USERNS
375 zpl_snapdir_mkdir(struct user_namespace *user_ns, struct inode *dip,
376     struct dentry *dentry, umode_t mode)
377 #elif defined(HAVE_IOPS_MKDIR_IDMAP)
378 zpl_snapdir_mkdir(struct mnt_idmap *user_ns, struct inode *dip,
379     struct dentry *dentry, umode_t mode)
380 #else
381 zpl_snapdir_mkdir(struct inode *dip, struct dentry *dentry, umode_t mode)
382 #endif
383 {
384 	cred_t *cr = CRED();
385 	vattr_t *vap;
386 	struct inode *ip;
387 	int error;
388 
389 	crhold(cr);
390 	vap = kmem_zalloc(sizeof (vattr_t), KM_SLEEP);
391 #if (defined(HAVE_IOPS_MKDIR_USERNS) || defined(HAVE_IOPS_MKDIR_IDMAP))
392 	zpl_vap_init(vap, dip, mode | S_IFDIR, cr, user_ns);
393 #else
394 	zpl_vap_init(vap, dip, mode | S_IFDIR, cr, zfs_init_idmap);
395 #endif
396 
397 	error = -zfsctl_snapdir_mkdir(dip, dname(dentry), vap, &ip, cr, 0);
398 	if (error == 0) {
399 		d_clear_d_op(dentry);
400 		d_set_d_op(dentry, &zpl_dops_snapdirs);
401 		d_instantiate(dentry, ip);
402 	}
403 
404 	kmem_free(vap, sizeof (vattr_t));
405 	ASSERT3S(error, <=, 0);
406 	crfree(cr);
407 
408 	return (error);
409 }
410 
411 /*
412  * Get snapshot directory attributes.
413  */
414 static int
415 #ifdef HAVE_IDMAP_IOPS_GETATTR
416 zpl_snapdir_getattr_impl(struct mnt_idmap *user_ns,
417     const struct path *path, struct kstat *stat, u32 request_mask,
418     unsigned int query_flags)
419 #elif defined(HAVE_USERNS_IOPS_GETATTR)
420 zpl_snapdir_getattr_impl(struct user_namespace *user_ns,
421     const struct path *path, struct kstat *stat, u32 request_mask,
422     unsigned int query_flags)
423 #else
424 zpl_snapdir_getattr_impl(const struct path *path, struct kstat *stat,
425     u32 request_mask, unsigned int query_flags)
426 #endif
427 {
428 	(void) request_mask, (void) query_flags;
429 	struct inode *ip = path->dentry->d_inode;
430 	zfsvfs_t *zfsvfs = ITOZSB(ip);
431 	int error;
432 
433 	if ((error = zpl_enter(zfsvfs, FTAG)) != 0)
434 		return (error);
435 #if (defined(HAVE_USERNS_IOPS_GETATTR) || defined(HAVE_IDMAP_IOPS_GETATTR))
436 #ifdef HAVE_GENERIC_FILLATTR_USERNS
437 	generic_fillattr(user_ns, ip, stat);
438 #elif defined(HAVE_GENERIC_FILLATTR_IDMAP)
439 	generic_fillattr(user_ns, ip, stat);
440 #elif defined(HAVE_GENERIC_FILLATTR_IDMAP_REQMASK)
441 	generic_fillattr(user_ns, request_mask, ip, stat);
442 #else
443 	(void) user_ns;
444 #endif
445 #else
446 	generic_fillattr(ip, stat);
447 #endif
448 
449 	stat->nlink = stat->size = 2;
450 
451 	dsl_dataset_t *ds = dmu_objset_ds(zfsvfs->z_os);
452 	if (dsl_dataset_phys(ds)->ds_snapnames_zapobj != 0) {
453 		uint64_t snap_count;
454 		int err = zap_count(
455 		    dmu_objset_pool(ds->ds_objset)->dp_meta_objset,
456 		    dsl_dataset_phys(ds)->ds_snapnames_zapobj, &snap_count);
457 		if (err != 0) {
458 			zpl_exit(zfsvfs, FTAG);
459 			return (-err);
460 		}
461 		stat->nlink += snap_count;
462 	}
463 
464 	stat->ctime = stat->mtime = dmu_objset_snap_cmtime(zfsvfs->z_os);
465 	stat->atime = current_time(ip);
466 	zpl_exit(zfsvfs, FTAG);
467 
468 	return (0);
469 }
470 ZPL_GETATTR_WRAPPER(zpl_snapdir_getattr);
471 
472 /*
473  * The '.zfs/snapshot' directory file operations.  These mainly control
474  * generating the list of available snapshots when doing an 'ls' in the
475  * directory.  See zpl_snapdir_readdir().
476  */
477 const struct file_operations zpl_fops_snapdir = {
478 	.open		= zpl_common_open,
479 	.llseek		= generic_file_llseek,
480 	.read		= generic_read_dir,
481 #ifdef HAVE_VFS_ITERATE_SHARED
482 	.iterate_shared	= zpl_snapdir_iterate,
483 #elif defined(HAVE_VFS_ITERATE)
484 	.iterate	= zpl_snapdir_iterate,
485 #else
486 	.readdir	= zpl_snapdir_readdir,
487 #endif
488 
489 };
490 
491 /*
492  * The '.zfs/snapshot' directory inode operations.  These mainly control
493  * creating an inode for a snapshot directory and initializing the needed
494  * infrastructure to automount the snapshot.  See zpl_snapdir_lookup().
495  */
496 const struct inode_operations zpl_ops_snapdir = {
497 	.lookup		= zpl_snapdir_lookup,
498 	.getattr	= zpl_snapdir_getattr,
499 #if (defined(HAVE_RENAME_WANTS_FLAGS) || \
500 	defined(HAVE_IOPS_RENAME_USERNS) || \
501 	defined(HAVE_IOPS_RENAME_IDMAP))
502 	.rename		= zpl_snapdir_rename2,
503 #else
504 	.rename		= zpl_snapdir_rename,
505 #endif
506 	.rmdir		= zpl_snapdir_rmdir,
507 	.mkdir		= zpl_snapdir_mkdir,
508 };
509 
510 static struct dentry *
511 zpl_shares_lookup(struct inode *dip, struct dentry *dentry,
512     unsigned int flags)
513 {
514 	fstrans_cookie_t cookie;
515 	cred_t *cr = CRED();
516 	struct inode *ip = NULL;
517 	int error;
518 
519 	crhold(cr);
520 	cookie = spl_fstrans_mark();
521 	error = -zfsctl_shares_lookup(dip, dname(dentry), &ip,
522 	    0, cr, NULL, NULL);
523 	ASSERT3S(error, <=, 0);
524 	spl_fstrans_unmark(cookie);
525 	crfree(cr);
526 
527 	if (error) {
528 		if (error == -ENOENT)
529 			return (d_splice_alias(NULL, dentry));
530 		else
531 			return (ERR_PTR(error));
532 	}
533 
534 	return (d_splice_alias(ip, dentry));
535 }
536 
537 static int
538 zpl_shares_iterate(struct file *filp, zpl_dir_context_t *ctx)
539 {
540 	fstrans_cookie_t cookie;
541 	cred_t *cr = CRED();
542 	zfsvfs_t *zfsvfs = ITOZSB(file_inode(filp));
543 	znode_t *dzp;
544 	int error = 0;
545 
546 	if ((error = zpl_enter(zfsvfs, FTAG)) != 0)
547 		return (error);
548 	cookie = spl_fstrans_mark();
549 
550 	if (zfsvfs->z_shares_dir == 0) {
551 		zpl_dir_emit_dots(filp, ctx);
552 		goto out;
553 	}
554 
555 	error = -zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp);
556 	if (error)
557 		goto out;
558 
559 	crhold(cr);
560 	error = -zfs_readdir(ZTOI(dzp), ctx, cr);
561 	crfree(cr);
562 
563 	iput(ZTOI(dzp));
564 out:
565 	spl_fstrans_unmark(cookie);
566 	zpl_exit(zfsvfs, FTAG);
567 	ASSERT3S(error, <=, 0);
568 
569 	return (error);
570 }
571 
572 #if !defined(HAVE_VFS_ITERATE) && !defined(HAVE_VFS_ITERATE_SHARED)
573 static int
574 zpl_shares_readdir(struct file *filp, void *dirent, filldir_t filldir)
575 {
576 	zpl_dir_context_t ctx =
577 	    ZPL_DIR_CONTEXT_INIT(dirent, filldir, filp->f_pos);
578 	int error;
579 
580 	error = zpl_shares_iterate(filp, &ctx);
581 	filp->f_pos = ctx.pos;
582 
583 	return (error);
584 }
585 #endif /* !HAVE_VFS_ITERATE && !HAVE_VFS_ITERATE_SHARED */
586 
587 static int
588 #ifdef HAVE_USERNS_IOPS_GETATTR
589 zpl_shares_getattr_impl(struct user_namespace *user_ns,
590     const struct path *path, struct kstat *stat, u32 request_mask,
591     unsigned int query_flags)
592 #elif defined(HAVE_IDMAP_IOPS_GETATTR)
593 zpl_shares_getattr_impl(struct mnt_idmap *user_ns,
594     const struct path *path, struct kstat *stat, u32 request_mask,
595     unsigned int query_flags)
596 #else
597 zpl_shares_getattr_impl(const struct path *path, struct kstat *stat,
598     u32 request_mask, unsigned int query_flags)
599 #endif
600 {
601 	(void) request_mask, (void) query_flags;
602 	struct inode *ip = path->dentry->d_inode;
603 	zfsvfs_t *zfsvfs = ITOZSB(ip);
604 	znode_t *dzp;
605 	int error;
606 
607 	if ((error = zpl_enter(zfsvfs, FTAG)) != 0)
608 		return (error);
609 
610 	if (zfsvfs->z_shares_dir == 0) {
611 #if (defined(HAVE_USERNS_IOPS_GETATTR) || defined(HAVE_IDMAP_IOPS_GETATTR))
612 #ifdef HAVE_GENERIC_FILLATTR_USERNS
613 		generic_fillattr(user_ns, path->dentry->d_inode, stat);
614 #elif defined(HAVE_GENERIC_FILLATTR_IDMAP)
615 		generic_fillattr(user_ns, path->dentry->d_inode, stat);
616 #elif defined(HAVE_GENERIC_FILLATTR_IDMAP_REQMASK)
617 	generic_fillattr(user_ns, request_mask, ip, stat);
618 #else
619 		(void) user_ns;
620 #endif
621 #else
622 		generic_fillattr(path->dentry->d_inode, stat);
623 #endif
624 		stat->nlink = stat->size = 2;
625 		stat->atime = current_time(ip);
626 		zpl_exit(zfsvfs, FTAG);
627 		return (0);
628 	}
629 
630 	error = -zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp);
631 	if (error == 0) {
632 #ifdef HAVE_GENERIC_FILLATTR_IDMAP_REQMASK
633 		error = -zfs_getattr_fast(user_ns, request_mask, ZTOI(dzp),
634 		    stat);
635 #elif (defined(HAVE_USERNS_IOPS_GETATTR) || defined(HAVE_IDMAP_IOPS_GETATTR))
636 		error = -zfs_getattr_fast(user_ns, ZTOI(dzp), stat);
637 #else
638 		error = -zfs_getattr_fast(kcred->user_ns, ZTOI(dzp), stat);
639 #endif
640 		iput(ZTOI(dzp));
641 	}
642 
643 	zpl_exit(zfsvfs, FTAG);
644 	ASSERT3S(error, <=, 0);
645 
646 	return (error);
647 }
648 ZPL_GETATTR_WRAPPER(zpl_shares_getattr);
649 
650 /*
651  * The '.zfs/shares' directory file operations.
652  */
653 const struct file_operations zpl_fops_shares = {
654 	.open		= zpl_common_open,
655 	.llseek		= generic_file_llseek,
656 	.read		= generic_read_dir,
657 #ifdef HAVE_VFS_ITERATE_SHARED
658 	.iterate_shared	= zpl_shares_iterate,
659 #elif defined(HAVE_VFS_ITERATE)
660 	.iterate	= zpl_shares_iterate,
661 #else
662 	.readdir	= zpl_shares_readdir,
663 #endif
664 
665 };
666 
667 /*
668  * The '.zfs/shares' directory inode operations.
669  */
670 const struct inode_operations zpl_ops_shares = {
671 	.lookup		= zpl_shares_lookup,
672 	.getattr	= zpl_shares_getattr,
673 };
674