1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright (c) 2013 by Delphix. All rights reserved.
24 */
25
26 /*
27 * ZFS control directory (a.k.a. ".zfs")
28 *
29 * This directory provides a common location for all ZFS meta-objects.
30 * Currently, this is only the 'snapshot' directory, but this may expand in the
31 * future. The elements are built using the GFS primitives, as the hierarchy
32 * does not actually exist on disk.
33 *
34 * For 'snapshot', we don't want to have all snapshots always mounted, because
35 * this would take up a huge amount of space in /etc/mnttab. We have three
36 * types of objects:
37 *
38 * ctldir ------> snapshotdir -------> snapshot
39 * |
40 * |
41 * V
42 * mounted fs
43 *
44 * The 'snapshot' node contains just enough information to lookup '..' and act
45 * as a mountpoint for the snapshot. Whenever we lookup a specific snapshot, we
46 * perform an automount of the underlying filesystem and return the
47 * corresponding vnode.
48 *
49 * All mounts are handled automatically by the kernel, but unmounts are
50 * (currently) handled from user land. The main reason is that there is no
51 * reliable way to auto-unmount the filesystem when it's "no longer in use".
52 * When the user unmounts a filesystem, we call zfsctl_unmount(), which
53 * unmounts any snapshots within the snapshot directory.
54 *
55 * The '.zfs', '.zfs/snapshot', and all directories created under
56 * '.zfs/snapshot' (ie: '.zfs/snapshot/<snapname>') are all GFS nodes and
57 * share the same vfs_t as the head filesystem (what '.zfs' lives under).
58 *
59 * File systems mounted ontop of the GFS nodes '.zfs/snapshot/<snapname>'
60 * (ie: snapshots) are ZFS nodes and have their own unique vfs_t.
61 * However, vnodes within these mounted on file systems have their v_vfsp
62 * fields set to the head filesystem to make NFS happy (see
63 * zfsctl_snapdir_lookup()). We VFS_HOLD the head filesystem's vfs_t
64 * so that it cannot be freed until all snapshots have been unmounted.
65 */
66
67 #include <fs/fs_subr.h>
68 #include <sys/zfs_ctldir.h>
69 #include <sys/zfs_ioctl.h>
70 #include <sys/zfs_vfsops.h>
71 #include <sys/vfs_opreg.h>
72 #include <sys/gfs.h>
73 #include <sys/stat.h>
74 #include <sys/dmu.h>
75 #include <sys/dsl_destroy.h>
76 #include <sys/dsl_deleg.h>
77 #include <sys/mount.h>
78 #include <sys/sunddi.h>
79
80 #include "zfs_namecheck.h"
81
82 typedef struct zfsctl_node {
83 gfs_dir_t zc_gfs_private;
84 uint64_t zc_id;
85 timestruc_t zc_cmtime; /* ctime and mtime, always the same */
86 } zfsctl_node_t;
87
88 typedef struct zfsctl_snapdir {
89 zfsctl_node_t sd_node;
90 kmutex_t sd_lock;
91 avl_tree_t sd_snaps;
92 } zfsctl_snapdir_t;
93
94 typedef struct {
95 char *se_name;
96 vnode_t *se_root;
97 avl_node_t se_node;
98 } zfs_snapentry_t;
99
100 static int
101 snapentry_compare(const void *a, const void *b)
102 {
103 const zfs_snapentry_t *sa = a;
104 const zfs_snapentry_t *sb = b;
105 int ret = strcmp(sa->se_name, sb->se_name);
106
107 if (ret < 0)
108 return (-1);
109 else if (ret > 0)
110 return (1);
111 else
112 return (0);
113 }
114
115 vnodeops_t *zfsctl_ops_root;
116 vnodeops_t *zfsctl_ops_snapdir;
117 vnodeops_t *zfsctl_ops_snapshot;
118 vnodeops_t *zfsctl_ops_shares;
119 vnodeops_t *zfsctl_ops_shares_dir;
120
121 static const fs_operation_def_t zfsctl_tops_root[];
122 static const fs_operation_def_t zfsctl_tops_snapdir[];
123 static const fs_operation_def_t zfsctl_tops_snapshot[];
124 static const fs_operation_def_t zfsctl_tops_shares[];
125
126 static vnode_t *zfsctl_mknode_snapdir(vnode_t *);
127 static vnode_t *zfsctl_mknode_shares(vnode_t *);
128 static vnode_t *zfsctl_snapshot_mknode(vnode_t *, uint64_t objset);
129 static int zfsctl_unmount_snap(zfs_snapentry_t *, int, cred_t *);
130
131 static gfs_opsvec_t zfsctl_opsvec[] = {
132 { ".zfs", zfsctl_tops_root, &zfsctl_ops_root },
133 { ".zfs/snapshot", zfsctl_tops_snapdir, &zfsctl_ops_snapdir },
134 { ".zfs/snapshot/vnode", zfsctl_tops_snapshot, &zfsctl_ops_snapshot },
135 { ".zfs/shares", zfsctl_tops_shares, &zfsctl_ops_shares_dir },
136 { ".zfs/shares/vnode", zfsctl_tops_shares, &zfsctl_ops_shares },
137 { NULL }
138 };
139
140 /*
141 * Root directory elements. We only have two entries
142 * snapshot and shares.
143 */
144 static gfs_dirent_t zfsctl_root_entries[] = {
145 { "snapshot", zfsctl_mknode_snapdir, GFS_CACHE_VNODE },
146 { "shares", zfsctl_mknode_shares, GFS_CACHE_VNODE },
147 { NULL }
148 };
149
150 /* include . and .. in the calculation */
151 #define NROOT_ENTRIES ((sizeof (zfsctl_root_entries) / \
152 sizeof (gfs_dirent_t)) + 1)
153
154
155 /*
156 * Initialize the various GFS pieces we'll need to create and manipulate .zfs
157 * directories. This is called from the ZFS init routine, and initializes the
158 * vnode ops vectors that we'll be using.
159 */
160 void
161 zfsctl_init(void)
162 {
163 VERIFY(gfs_make_opsvec(zfsctl_opsvec) == 0);
164 }
165
166 void
167 zfsctl_fini(void)
168 {
169 /*
170 * Remove vfsctl vnode ops
171 */
172 if (zfsctl_ops_root)
173 vn_freevnodeops(zfsctl_ops_root);
174 if (zfsctl_ops_snapdir)
175 vn_freevnodeops(zfsctl_ops_snapdir);
176 if (zfsctl_ops_snapshot)
177 vn_freevnodeops(zfsctl_ops_snapshot);
178 if (zfsctl_ops_shares)
179 vn_freevnodeops(zfsctl_ops_shares);
180 if (zfsctl_ops_shares_dir)
181 vn_freevnodeops(zfsctl_ops_shares_dir);
182
183 zfsctl_ops_root = NULL;
184 zfsctl_ops_snapdir = NULL;
185 zfsctl_ops_snapshot = NULL;
186 zfsctl_ops_shares = NULL;
187 zfsctl_ops_shares_dir = NULL;
188 }
189
190 boolean_t
191 zfsctl_is_node(vnode_t *vp)
192 {
193 return (vn_matchops(vp, zfsctl_ops_root) ||
194 vn_matchops(vp, zfsctl_ops_snapdir) ||
195 vn_matchops(vp, zfsctl_ops_snapshot) ||
196 vn_matchops(vp, zfsctl_ops_shares) ||
197 vn_matchops(vp, zfsctl_ops_shares_dir));
198
199 }
200
201 /*
202 * Return the inode number associated with the 'snapshot' or
203 * 'shares' directory.
204 */
205 /* ARGSUSED */
206 static ino64_t
207 zfsctl_root_inode_cb(vnode_t *vp, int index)
208 {
209 zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
210
211 ASSERT(index <= 2);
212
213 if (index == 0)
214 return (ZFSCTL_INO_SNAPDIR);
215
216 return (zfsvfs->z_shares_dir);
217 }
218
219 /*
220 * Create the '.zfs' directory. This directory is cached as part of the VFS
221 * structure. This results in a hold on the vfs_t. The code in zfs_umount()
222 * therefore checks against a vfs_count of 2 instead of 1. This reference
223 * is removed when the ctldir is destroyed in the unmount.
224 */
225 void
226 zfsctl_create(zfsvfs_t *zfsvfs)
227 {
228 vnode_t *vp, *rvp;
229 zfsctl_node_t *zcp;
230 uint64_t crtime[2];
231
232 ASSERT(zfsvfs->z_ctldir == NULL);
233
234 vp = gfs_root_create(sizeof (zfsctl_node_t), zfsvfs->z_vfs,
235 zfsctl_ops_root, ZFSCTL_INO_ROOT, zfsctl_root_entries,
236 zfsctl_root_inode_cb, MAXNAMELEN, NULL, NULL);
237 zcp = vp->v_data;
238 zcp->zc_id = ZFSCTL_INO_ROOT;
239
240 VERIFY(VFS_ROOT(zfsvfs->z_vfs, &rvp) == 0);
241 VERIFY(0 == sa_lookup(VTOZ(rvp)->z_sa_hdl, SA_ZPL_CRTIME(zfsvfs),
242 &crtime, sizeof (crtime)));
243 ZFS_TIME_DECODE(&zcp->zc_cmtime, crtime);
244 VN_RELE(rvp);
245
246 /*
247 * We're only faking the fact that we have a root of a filesystem for
248 * the sake of the GFS interfaces. Undo the flag manipulation it did
249 * for us.
250 */
251 vp->v_flag &= ~(VROOT | VNOCACHE | VNOMAP | VNOSWAP | VNOMOUNT);
252
253 zfsvfs->z_ctldir = vp;
254 }
255
256 /*
257 * Destroy the '.zfs' directory. Only called when the filesystem is unmounted.
258 * There might still be more references if we were force unmounted, but only
259 * new zfs_inactive() calls can occur and they don't reference .zfs
260 */
261 void
262 zfsctl_destroy(zfsvfs_t *zfsvfs)
263 {
264 VN_RELE(zfsvfs->z_ctldir);
265 zfsvfs->z_ctldir = NULL;
266 }
267
268 /*
269 * Given a root znode, retrieve the associated .zfs directory.
270 * Add a hold to the vnode and return it.
271 */
272 vnode_t *
273 zfsctl_root(znode_t *zp)
274 {
275 ASSERT(zfs_has_ctldir(zp));
276 VN_HOLD(zp->z_zfsvfs->z_ctldir);
277 return (zp->z_zfsvfs->z_ctldir);
278 }
279
280 /*
281 * Common open routine. Disallow any write access.
282 */
283 /* ARGSUSED */
284 static int
285 zfsctl_common_open(vnode_t **vpp, int flags, cred_t *cr, caller_context_t *ct)
286 {
287 if (flags & FWRITE)
288 return (SET_ERROR(EACCES));
289
290 return (0);
291 }
292
293 /*
294 * Common close routine. Nothing to do here.
295 */
296 /* ARGSUSED */
297 static int
298 zfsctl_common_close(vnode_t *vpp, int flags, int count, offset_t off,
299 cred_t *cr, caller_context_t *ct)
300 {
301 return (0);
302 }
303
304 /*
305 * Common access routine. Disallow writes.
306 */
307 /* ARGSUSED */
308 static int
309 zfsctl_common_access(vnode_t *vp, int mode, int flags, cred_t *cr,
310 caller_context_t *ct)
311 {
312 if (flags & V_ACE_MASK) {
313 if (mode & ACE_ALL_WRITE_PERMS)
314 return (SET_ERROR(EACCES));
315 } else {
316 if (mode & VWRITE)
317 return (SET_ERROR(EACCES));
318 }
319
320 return (0);
321 }
322
323 /*
324 * Common getattr function. Fill in basic information.
325 */
326 static void
327 zfsctl_common_getattr(vnode_t *vp, vattr_t *vap)
328 {
329 timestruc_t now;
330
331 vap->va_uid = 0;
332 vap->va_gid = 0;
333 vap->va_rdev = 0;
334 /*
335 * We are a purely virtual object, so we have no
336 * blocksize or allocated blocks.
337 */
338 vap->va_blksize = 0;
339 vap->va_nblocks = 0;
340 vap->va_seq = 0;
341 vap->va_fsid = vp->v_vfsp->vfs_dev;
342 vap->va_mode = S_IRUSR | S_IXUSR | S_IRGRP | S_IXGRP |
343 S_IROTH | S_IXOTH;
344 vap->va_type = VDIR;
345 /*
346 * We live in the now (for atime).
347 */
348 gethrestime(&now);
349 vap->va_atime = now;
350 }
351
352 /*ARGSUSED*/
353 static int
354 zfsctl_common_fid(vnode_t *vp, fid_t *fidp, caller_context_t *ct)
355 {
356 zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
357 zfsctl_node_t *zcp = vp->v_data;
358 uint64_t object = zcp->zc_id;
359 zfid_short_t *zfid;
360 int i;
361
362 ZFS_ENTER(zfsvfs);
363
364 if (fidp->fid_len < SHORT_FID_LEN) {
365 fidp->fid_len = SHORT_FID_LEN;
366 ZFS_EXIT(zfsvfs);
367 return (SET_ERROR(ENOSPC));
368 }
369
370 zfid = (zfid_short_t *)fidp;
371
372 zfid->zf_len = SHORT_FID_LEN;
373
374 for (i = 0; i < sizeof (zfid->zf_object); i++)
375 zfid->zf_object[i] = (uint8_t)(object >> (8 * i));
376
377 /* .zfs znodes always have a generation number of 0 */
378 for (i = 0; i < sizeof (zfid->zf_gen); i++)
379 zfid->zf_gen[i] = 0;
380
381 ZFS_EXIT(zfsvfs);
382 return (0);
383 }
384
385
386 /*ARGSUSED*/
387 static int
388 zfsctl_shares_fid(vnode_t *vp, fid_t *fidp, caller_context_t *ct)
389 {
390 zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
391 znode_t *dzp;
392 int error;
393
394 ZFS_ENTER(zfsvfs);
395
396 if (zfsvfs->z_shares_dir == 0) {
397 ZFS_EXIT(zfsvfs);
398 return (SET_ERROR(ENOTSUP));
399 }
400
401 if ((error = zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp)) == 0) {
402 error = VOP_FID(ZTOV(dzp), fidp, ct);
403 VN_RELE(ZTOV(dzp));
404 }
405
406 ZFS_EXIT(zfsvfs);
407 return (error);
408 }
409 /*
410 * .zfs inode namespace
411 *
412 * We need to generate unique inode numbers for all files and directories
413 * within the .zfs pseudo-filesystem. We use the following scheme:
414 *
415 * ENTRY ZFSCTL_INODE
416 * .zfs 1
417 * .zfs/snapshot 2
418 * .zfs/snapshot/<snap> objectid(snap)
419 */
420
421 #define ZFSCTL_INO_SNAP(id) (id)
422
423 /*
424 * Get root directory attributes.
425 */
426 /* ARGSUSED */
427 static int
428 zfsctl_root_getattr(vnode_t *vp, vattr_t *vap, int flags, cred_t *cr,
429 caller_context_t *ct)
430 {
431 zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
432 zfsctl_node_t *zcp = vp->v_data;
433
434 ZFS_ENTER(zfsvfs);
435 vap->va_nodeid = ZFSCTL_INO_ROOT;
436 vap->va_nlink = vap->va_size = NROOT_ENTRIES;
437 vap->va_mtime = vap->va_ctime = zcp->zc_cmtime;
438
439 zfsctl_common_getattr(vp, vap);
440 ZFS_EXIT(zfsvfs);
441
442 return (0);
443 }
444
445 /*
446 * Special case the handling of "..".
447 */
448 /* ARGSUSED */
449 int
450 zfsctl_root_lookup(vnode_t *dvp, char *nm, vnode_t **vpp, pathname_t *pnp,
451 int flags, vnode_t *rdir, cred_t *cr, caller_context_t *ct,
452 int *direntflags, pathname_t *realpnp)
453 {
454 zfsvfs_t *zfsvfs = dvp->v_vfsp->vfs_data;
455 int err;
456
457 /*
458 * No extended attributes allowed under .zfs
459 */
460 if (flags & LOOKUP_XATTR)
461 return (SET_ERROR(EINVAL));
462
463 ZFS_ENTER(zfsvfs);
464
465 if (strcmp(nm, "..") == 0) {
466 err = VFS_ROOT(dvp->v_vfsp, vpp);
467 } else {
468 err = gfs_vop_lookup(dvp, nm, vpp, pnp, flags, rdir,
469 cr, ct, direntflags, realpnp);
470 }
471
472 ZFS_EXIT(zfsvfs);
473
474 return (err);
475 }
476
477 static int
478 zfsctl_pathconf(vnode_t *vp, int cmd, ulong_t *valp, cred_t *cr,
479 caller_context_t *ct)
480 {
481 /*
482 * We only care about ACL_ENABLED so that libsec can
483 * display ACL correctly and not default to POSIX draft.
484 */
485 if (cmd == _PC_ACL_ENABLED) {
486 *valp = _ACL_ACE_ENABLED;
487 return (0);
488 }
489
490 return (fs_pathconf(vp, cmd, valp, cr, ct));
491 }
492
493 static const fs_operation_def_t zfsctl_tops_root[] = {
494 { VOPNAME_OPEN, { .vop_open = zfsctl_common_open } },
495 { VOPNAME_CLOSE, { .vop_close = zfsctl_common_close } },
496 { VOPNAME_IOCTL, { .error = fs_inval } },
497 { VOPNAME_GETATTR, { .vop_getattr = zfsctl_root_getattr } },
498 { VOPNAME_ACCESS, { .vop_access = zfsctl_common_access } },
499 { VOPNAME_READDIR, { .vop_readdir = gfs_vop_readdir } },
500 { VOPNAME_LOOKUP, { .vop_lookup = zfsctl_root_lookup } },
501 { VOPNAME_SEEK, { .vop_seek = fs_seek } },
502 { VOPNAME_INACTIVE, { .vop_inactive = gfs_vop_inactive } },
503 { VOPNAME_PATHCONF, { .vop_pathconf = zfsctl_pathconf } },
504 { VOPNAME_FID, { .vop_fid = zfsctl_common_fid } },
505 { NULL }
506 };
507
508 /*
509 * Gets the full dataset name that corresponds to the given snapshot name
510 * Example:
511 * zfsctl_snapshot_zname("snap1") -> "mypool/myfs@snap1"
512 */
513 static int
514 zfsctl_snapshot_zname(vnode_t *vp, const char *name, int len, char *zname)
515 {
516 objset_t *os = ((zfsvfs_t *)((vp)->v_vfsp->vfs_data))->z_os;
517
518 if (snapshot_namecheck(name, NULL, NULL) != 0)
519 return (SET_ERROR(EILSEQ));
520 dmu_objset_name(os, zname);
521 if (strlen(zname) + 1 + strlen(name) >= len)
522 return (SET_ERROR(ENAMETOOLONG));
523 (void) strcat(zname, "@");
524 (void) strcat(zname, name);
525 return (0);
526 }
527
528 static int
529 zfsctl_unmount_snap(zfs_snapentry_t *sep, int fflags, cred_t *cr)
530 {
531 vnode_t *svp = sep->se_root;
532 int error;
533
534 ASSERT(vn_ismntpt(svp));
535
536 /* this will be dropped by dounmount() */
537 if ((error = vn_vfswlock(svp)) != 0)
538 return (error);
539
540 VN_HOLD(svp);
541 error = dounmount(vn_mountedvfs(svp), fflags, cr);
542 if (error) {
543 VN_RELE(svp);
544 return (error);
545 }
546
547 /*
548 * We can't use VN_RELE(), as that will try to invoke
549 * zfsctl_snapdir_inactive(), which would cause us to destroy
550 * the sd_lock mutex held by our caller.
551 */
552 ASSERT(svp->v_count == 1);
553 gfs_vop_inactive(svp, cr, NULL);
554
555 kmem_free(sep->se_name, strlen(sep->se_name) + 1);
556 kmem_free(sep, sizeof (zfs_snapentry_t));
557
558 return (0);
559 }
560
561 static void
562 zfsctl_rename_snap(zfsctl_snapdir_t *sdp, zfs_snapentry_t *sep, const char *nm)
563 {
564 avl_index_t where;
565 vfs_t *vfsp;
566 refstr_t *pathref;
567 char newpath[MAXNAMELEN];
568 char *tail;
569
570 ASSERT(MUTEX_HELD(&sdp->sd_lock));
571 ASSERT(sep != NULL);
572
573 vfsp = vn_mountedvfs(sep->se_root);
574 ASSERT(vfsp != NULL);
575
576 vfs_lock_wait(vfsp);
577
578 /*
579 * Change the name in the AVL tree.
580 */
581 avl_remove(&sdp->sd_snaps, sep);
582 kmem_free(sep->se_name, strlen(sep->se_name) + 1);
583 sep->se_name = kmem_alloc(strlen(nm) + 1, KM_SLEEP);
584 (void) strcpy(sep->se_name, nm);
585 VERIFY(avl_find(&sdp->sd_snaps, sep, &where) == NULL);
586 avl_insert(&sdp->sd_snaps, sep, where);
587
588 /*
589 * Change the current mountpoint info:
590 * - update the tail of the mntpoint path
591 * - update the tail of the resource path
592 */
593 pathref = vfs_getmntpoint(vfsp);
594 (void) strncpy(newpath, refstr_value(pathref), sizeof (newpath));
595 VERIFY((tail = strrchr(newpath, '/')) != NULL);
596 *(tail+1) = '\0';
597 ASSERT3U(strlen(newpath) + strlen(nm), <, sizeof (newpath));
598 (void) strcat(newpath, nm);
599 refstr_rele(pathref);
600 vfs_setmntpoint(vfsp, newpath, 0);
601
602 pathref = vfs_getresource(vfsp);
603 (void) strncpy(newpath, refstr_value(pathref), sizeof (newpath));
604 VERIFY((tail = strrchr(newpath, '@')) != NULL);
605 *(tail+1) = '\0';
606 ASSERT3U(strlen(newpath) + strlen(nm), <, sizeof (newpath));
607 (void) strcat(newpath, nm);
608 refstr_rele(pathref);
609 vfs_setresource(vfsp, newpath, 0);
610
611 vfs_unlock(vfsp);
612 }
613
614 /*ARGSUSED*/
615 static int
616 zfsctl_snapdir_rename(vnode_t *sdvp, char *snm, vnode_t *tdvp, char *tnm,
617 cred_t *cr, caller_context_t *ct, int flags)
618 {
619 zfsctl_snapdir_t *sdp = sdvp->v_data;
620 zfs_snapentry_t search, *sep;
621 zfsvfs_t *zfsvfs;
622 avl_index_t where;
623 char from[MAXNAMELEN], to[MAXNAMELEN];
624 char real[MAXNAMELEN], fsname[MAXNAMELEN];
625 int err;
626
627 zfsvfs = sdvp->v_vfsp->vfs_data;
628 ZFS_ENTER(zfsvfs);
629
630 if ((flags & FIGNORECASE) || zfsvfs->z_case == ZFS_CASE_INSENSITIVE) {
631 err = dmu_snapshot_realname(zfsvfs->z_os, snm, real,
632 MAXNAMELEN, NULL);
633 if (err == 0) {
634 snm = real;
635 } else if (err != ENOTSUP) {
636 ZFS_EXIT(zfsvfs);
637 return (err);
638 }
639 }
640
641 ZFS_EXIT(zfsvfs);
642
643 dmu_objset_name(zfsvfs->z_os, fsname);
644
645 err = zfsctl_snapshot_zname(sdvp, snm, MAXNAMELEN, from);
646 if (err == 0)
647 err = zfsctl_snapshot_zname(tdvp, tnm, MAXNAMELEN, to);
648 if (err == 0)
649 err = zfs_secpolicy_rename_perms(from, to, cr);
650 if (err != 0)
651 return (err);
652
653 /*
654 * Cannot move snapshots out of the snapdir.
655 */
656 if (sdvp != tdvp)
657 return (SET_ERROR(EINVAL));
658
659 if (strcmp(snm, tnm) == 0)
660 return (0);
661
662 mutex_enter(&sdp->sd_lock);
663
664 search.se_name = (char *)snm;
665 if ((sep = avl_find(&sdp->sd_snaps, &search, &where)) == NULL) {
666 mutex_exit(&sdp->sd_lock);
667 return (SET_ERROR(ENOENT));
668 }
669
670 err = dsl_dataset_rename_snapshot(fsname, snm, tnm, B_FALSE);
671 if (err == 0)
672 zfsctl_rename_snap(sdp, sep, tnm);
673
674 mutex_exit(&sdp->sd_lock);
675
676 return (err);
677 }
678
679 /* ARGSUSED */
680 static int
681 zfsctl_snapdir_remove(vnode_t *dvp, char *name, vnode_t *cwd, cred_t *cr,
682 caller_context_t *ct, int flags)
683 {
684 zfsctl_snapdir_t *sdp = dvp->v_data;
685 zfs_snapentry_t *sep;
686 zfs_snapentry_t search;
687 zfsvfs_t *zfsvfs;
688 char snapname[MAXNAMELEN];
689 char real[MAXNAMELEN];
690 int err;
691
692 zfsvfs = dvp->v_vfsp->vfs_data;
693 ZFS_ENTER(zfsvfs);
694
695 if ((flags & FIGNORECASE) || zfsvfs->z_case == ZFS_CASE_INSENSITIVE) {
696
697 err = dmu_snapshot_realname(zfsvfs->z_os, name, real,
698 MAXNAMELEN, NULL);
699 if (err == 0) {
700 name = real;
701 } else if (err != ENOTSUP) {
702 ZFS_EXIT(zfsvfs);
703 return (err);
704 }
705 }
706
707 ZFS_EXIT(zfsvfs);
708
709 err = zfsctl_snapshot_zname(dvp, name, MAXNAMELEN, snapname);
710 if (err == 0)
711 err = zfs_secpolicy_destroy_perms(snapname, cr);
712 if (err != 0)
713 return (err);
714
715 mutex_enter(&sdp->sd_lock);
716
717 search.se_name = name;
718 sep = avl_find(&sdp->sd_snaps, &search, NULL);
719 if (sep) {
720 avl_remove(&sdp->sd_snaps, sep);
721 err = zfsctl_unmount_snap(sep, MS_FORCE, cr);
722 if (err != 0)
723 avl_add(&sdp->sd_snaps, sep);
724 else
725 err = dsl_destroy_snapshot(snapname, B_FALSE);
726 } else {
727 err = SET_ERROR(ENOENT);
728 }
729
730 mutex_exit(&sdp->sd_lock);
731
732 return (err);
733 }
734
735 /*
736 * This creates a snapshot under '.zfs/snapshot'.
737 */
738 /* ARGSUSED */
739 static int
740 zfsctl_snapdir_mkdir(vnode_t *dvp, char *dirname, vattr_t *vap, vnode_t **vpp,
741 cred_t *cr, caller_context_t *cc, int flags, vsecattr_t *vsecp)
742 {
743 zfsvfs_t *zfsvfs = dvp->v_vfsp->vfs_data;
744 char name[MAXNAMELEN];
745 int err;
746 static enum symfollow follow = NO_FOLLOW;
747 static enum uio_seg seg = UIO_SYSSPACE;
748
749 if (snapshot_namecheck(dirname, NULL, NULL) != 0)
750 return (SET_ERROR(EILSEQ));
751
752 dmu_objset_name(zfsvfs->z_os, name);
753
754 *vpp = NULL;
755
756 err = zfs_secpolicy_snapshot_perms(name, cr);
757 if (err != 0)
758 return (err);
759
760 if (err == 0) {
761 err = dmu_objset_snapshot_one(name, dirname);
762 if (err != 0)
763 return (err);
764 err = lookupnameat(dirname, seg, follow, NULL, vpp, dvp);
765 }
766
767 return (err);
768 }
769
770 /*
771 * Lookup entry point for the 'snapshot' directory. Try to open the
772 * snapshot if it exist, creating the pseudo filesystem vnode as necessary.
773 * Perform a mount of the associated dataset on top of the vnode.
774 */
775 /* ARGSUSED */
776 static int
777 zfsctl_snapdir_lookup(vnode_t *dvp, char *nm, vnode_t **vpp, pathname_t *pnp,
778 int flags, vnode_t *rdir, cred_t *cr, caller_context_t *ct,
779 int *direntflags, pathname_t *realpnp)
780 {
781 zfsctl_snapdir_t *sdp = dvp->v_data;
782 objset_t *snap;
783 char snapname[MAXNAMELEN];
784 char real[MAXNAMELEN];
785 char *mountpoint;
786 zfs_snapentry_t *sep, search;
787 struct mounta margs;
788 vfs_t *vfsp;
789 size_t mountpoint_len;
790 avl_index_t where;
791 zfsvfs_t *zfsvfs = dvp->v_vfsp->vfs_data;
792 int err;
793
794 /*
795 * No extended attributes allowed under .zfs
796 */
797 if (flags & LOOKUP_XATTR)
798 return (SET_ERROR(EINVAL));
799
800 ASSERT(dvp->v_type == VDIR);
801
802 /*
803 * If we get a recursive call, that means we got called
804 * from the domount() code while it was trying to look up the
805 * spec (which looks like a local path for zfs). We need to
806 * add some flag to domount() to tell it not to do this lookup.
807 */
808 if (MUTEX_HELD(&sdp->sd_lock))
809 return (SET_ERROR(ENOENT));
810
811 ZFS_ENTER(zfsvfs);
812
813 if (gfs_lookup_dot(vpp, dvp, zfsvfs->z_ctldir, nm) == 0) {
814 ZFS_EXIT(zfsvfs);
815 return (0);
816 }
817
818 if (flags & FIGNORECASE) {
819 boolean_t conflict = B_FALSE;
820
821 err = dmu_snapshot_realname(zfsvfs->z_os, nm, real,
822 MAXNAMELEN, &conflict);
823 if (err == 0) {
824 nm = real;
825 } else if (err != ENOTSUP) {
826 ZFS_EXIT(zfsvfs);
827 return (err);
828 }
829 if (realpnp)
830 (void) strlcpy(realpnp->pn_buf, nm,
831 realpnp->pn_bufsize);
832 if (conflict && direntflags)
833 *direntflags = ED_CASE_CONFLICT;
834 }
835
836 mutex_enter(&sdp->sd_lock);
837 search.se_name = (char *)nm;
838 if ((sep = avl_find(&sdp->sd_snaps, &search, &where)) != NULL) {
839 *vpp = sep->se_root;
840 VN_HOLD(*vpp);
841 err = traverse(vpp);
842 if (err != 0) {
843 VN_RELE(*vpp);
844 *vpp = NULL;
845 } else if (*vpp == sep->se_root) {
846 /*
847 * The snapshot was unmounted behind our backs,
848 * try to remount it.
849 */
850 goto domount;
851 } else {
852 /*
853 * VROOT was set during the traverse call. We need
854 * to clear it since we're pretending to be part
855 * of our parent's vfs.
856 */
857 (*vpp)->v_flag &= ~VROOT;
858 }
859 mutex_exit(&sdp->sd_lock);
860 ZFS_EXIT(zfsvfs);
861 return (err);
862 }
863
864 /*
865 * The requested snapshot is not currently mounted, look it up.
866 */
867 err = zfsctl_snapshot_zname(dvp, nm, MAXNAMELEN, snapname);
868 if (err != 0) {
869 mutex_exit(&sdp->sd_lock);
870 ZFS_EXIT(zfsvfs);
871 /*
872 * handle "ls *" or "?" in a graceful manner,
873 * forcing EILSEQ to ENOENT.
874 * Since shell ultimately passes "*" or "?" as name to lookup
875 */
876 return (err == EILSEQ ? ENOENT : err);
877 }
878 if (dmu_objset_hold(snapname, FTAG, &snap) != 0) {
879 mutex_exit(&sdp->sd_lock);
880 ZFS_EXIT(zfsvfs);
881 return (SET_ERROR(ENOENT));
882 }
883
884 sep = kmem_alloc(sizeof (zfs_snapentry_t), KM_SLEEP);
885 sep->se_name = kmem_alloc(strlen(nm) + 1, KM_SLEEP);
886 (void) strcpy(sep->se_name, nm);
887 *vpp = sep->se_root = zfsctl_snapshot_mknode(dvp, dmu_objset_id(snap));
888 avl_insert(&sdp->sd_snaps, sep, where);
889
890 dmu_objset_rele(snap, FTAG);
891 domount:
892 mountpoint_len = strlen(refstr_value(dvp->v_vfsp->vfs_mntpt)) +
893 strlen("/.zfs/snapshot/") + strlen(nm) + 1;
894 mountpoint = kmem_alloc(mountpoint_len, KM_SLEEP);
895 (void) snprintf(mountpoint, mountpoint_len, "%s/.zfs/snapshot/%s",
896 refstr_value(dvp->v_vfsp->vfs_mntpt), nm);
897
898 margs.spec = snapname;
899 margs.dir = mountpoint;
900 margs.flags = MS_SYSSPACE | MS_NOMNTTAB;
901 margs.fstype = "zfs";
902 margs.dataptr = NULL;
903 margs.datalen = 0;
904 margs.optptr = NULL;
905 margs.optlen = 0;
906
907 err = domount("zfs", &margs, *vpp, kcred, &vfsp);
908 kmem_free(mountpoint, mountpoint_len);
909
910 if (err == 0) {
911 /*
912 * Return the mounted root rather than the covered mount point.
913 * Takes the GFS vnode at .zfs/snapshot/<snapname> and returns
914 * the ZFS vnode mounted on top of the GFS node. This ZFS
915 * vnode is the root of the newly created vfsp.
916 */
917 VFS_RELE(vfsp);
918 err = traverse(vpp);
919 }
920
921 if (err == 0) {
922 /*
923 * Fix up the root vnode mounted on .zfs/snapshot/<snapname>.
924 *
925 * This is where we lie about our v_vfsp in order to
926 * make .zfs/snapshot/<snapname> accessible over NFS
927 * without requiring manual mounts of <snapname>.
928 */
929 ASSERT(VTOZ(*vpp)->z_zfsvfs != zfsvfs);
930 VTOZ(*vpp)->z_zfsvfs->z_parent = zfsvfs;
931 (*vpp)->v_vfsp = zfsvfs->z_vfs;
932 (*vpp)->v_flag &= ~VROOT;
933 }
934 mutex_exit(&sdp->sd_lock);
935 ZFS_EXIT(zfsvfs);
936
937 /*
938 * If we had an error, drop our hold on the vnode and
939 * zfsctl_snapshot_inactive() will clean up.
940 */
941 if (err != 0) {
942 VN_RELE(*vpp);
943 *vpp = NULL;
944 }
945 return (err);
946 }
947
948 /* ARGSUSED */
949 static int
950 zfsctl_shares_lookup(vnode_t *dvp, char *nm, vnode_t **vpp, pathname_t *pnp,
951 int flags, vnode_t *rdir, cred_t *cr, caller_context_t *ct,
952 int *direntflags, pathname_t *realpnp)
953 {
954 zfsvfs_t *zfsvfs = dvp->v_vfsp->vfs_data;
955 znode_t *dzp;
956 int error;
957
958 ZFS_ENTER(zfsvfs);
959
960 if (gfs_lookup_dot(vpp, dvp, zfsvfs->z_ctldir, nm) == 0) {
961 ZFS_EXIT(zfsvfs);
962 return (0);
963 }
964
965 if (zfsvfs->z_shares_dir == 0) {
966 ZFS_EXIT(zfsvfs);
967 return (SET_ERROR(ENOTSUP));
968 }
969 if ((error = zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp)) == 0)
970 error = VOP_LOOKUP(ZTOV(dzp), nm, vpp, pnp,
971 flags, rdir, cr, ct, direntflags, realpnp);
972
973 VN_RELE(ZTOV(dzp));
974 ZFS_EXIT(zfsvfs);
975
976 return (error);
977 }
978
979 /* ARGSUSED */
980 static int
981 zfsctl_snapdir_readdir_cb(vnode_t *vp, void *dp, int *eofp,
982 offset_t *offp, offset_t *nextp, void *data, int flags)
983 {
984 zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
985 char snapname[MAXNAMELEN];
986 uint64_t id, cookie;
987 boolean_t case_conflict;
988 int error;
989
990 ZFS_ENTER(zfsvfs);
991
992 cookie = *offp;
993 dsl_pool_config_enter(dmu_objset_pool(zfsvfs->z_os), FTAG);
994 error = dmu_snapshot_list_next(zfsvfs->z_os, MAXNAMELEN, snapname, &id,
995 &cookie, &case_conflict);
996 dsl_pool_config_exit(dmu_objset_pool(zfsvfs->z_os), FTAG);
997 if (error) {
998 ZFS_EXIT(zfsvfs);
999 if (error == ENOENT) {
1000 *eofp = 1;
1001 return (0);
1002 }
1003 return (error);
1004 }
1005
1006 if (flags & V_RDDIR_ENTFLAGS) {
1007 edirent_t *eodp = dp;
1008
1009 (void) strcpy(eodp->ed_name, snapname);
1010 eodp->ed_ino = ZFSCTL_INO_SNAP(id);
1011 eodp->ed_eflags = case_conflict ? ED_CASE_CONFLICT : 0;
1012 } else {
1013 struct dirent64 *odp = dp;
1014
1015 (void) strcpy(odp->d_name, snapname);
1016 odp->d_ino = ZFSCTL_INO_SNAP(id);
1017 }
1018 *nextp = cookie;
1019
1020 ZFS_EXIT(zfsvfs);
1021
1022 return (0);
1023 }
1024
1025 /* ARGSUSED */
1026 static int
1027 zfsctl_shares_readdir(vnode_t *vp, uio_t *uiop, cred_t *cr, int *eofp,
1028 caller_context_t *ct, int flags)
1029 {
1030 zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
1031 znode_t *dzp;
1032 int error;
1033
1034 ZFS_ENTER(zfsvfs);
1035
1036 if (zfsvfs->z_shares_dir == 0) {
1037 ZFS_EXIT(zfsvfs);
1038 return (SET_ERROR(ENOTSUP));
1039 }
1040 if ((error = zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp)) == 0) {
1041 error = VOP_READDIR(ZTOV(dzp), uiop, cr, eofp, ct, flags);
1042 VN_RELE(ZTOV(dzp));
1043 } else {
1044 *eofp = 1;
1045 error = SET_ERROR(ENOENT);
1046 }
1047
1048 ZFS_EXIT(zfsvfs);
1049 return (error);
1050 }
1051
1052 /*
1053 * pvp is the '.zfs' directory (zfsctl_node_t).
1054 * Creates vp, which is '.zfs/snapshot' (zfsctl_snapdir_t).
1055 *
1056 * This function is the callback to create a GFS vnode for '.zfs/snapshot'
1057 * when a lookup is performed on .zfs for "snapshot".
1058 */
1059 vnode_t *
1060 zfsctl_mknode_snapdir(vnode_t *pvp)
1061 {
1062 vnode_t *vp;
1063 zfsctl_snapdir_t *sdp;
1064
1065 vp = gfs_dir_create(sizeof (zfsctl_snapdir_t), pvp,
1066 zfsctl_ops_snapdir, NULL, NULL, MAXNAMELEN,
1067 zfsctl_snapdir_readdir_cb, NULL);
1068 sdp = vp->v_data;
1069 sdp->sd_node.zc_id = ZFSCTL_INO_SNAPDIR;
1070 sdp->sd_node.zc_cmtime = ((zfsctl_node_t *)pvp->v_data)->zc_cmtime;
1071 mutex_init(&sdp->sd_lock, NULL, MUTEX_DEFAULT, NULL);
1072 avl_create(&sdp->sd_snaps, snapentry_compare,
1073 sizeof (zfs_snapentry_t), offsetof(zfs_snapentry_t, se_node));
1074 return (vp);
1075 }
1076
1077 vnode_t *
1078 zfsctl_mknode_shares(vnode_t *pvp)
1079 {
1080 vnode_t *vp;
1081 zfsctl_node_t *sdp;
1082
1083 vp = gfs_dir_create(sizeof (zfsctl_node_t), pvp,
1084 zfsctl_ops_shares, NULL, NULL, MAXNAMELEN,
1085 NULL, NULL);
1086 sdp = vp->v_data;
1087 sdp->zc_cmtime = ((zfsctl_node_t *)pvp->v_data)->zc_cmtime;
1088 return (vp);
1089
1090 }
1091
1092 /* ARGSUSED */
1093 static int
1094 zfsctl_shares_getattr(vnode_t *vp, vattr_t *vap, int flags, cred_t *cr,
1095 caller_context_t *ct)
1096 {
1097 zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
1098 znode_t *dzp;
1099 int error;
1100
1101 ZFS_ENTER(zfsvfs);
1102 if (zfsvfs->z_shares_dir == 0) {
1103 ZFS_EXIT(zfsvfs);
1104 return (SET_ERROR(ENOTSUP));
1105 }
1106 if ((error = zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp)) == 0) {
1107 error = VOP_GETATTR(ZTOV(dzp), vap, flags, cr, ct);
1108 VN_RELE(ZTOV(dzp));
1109 }
1110 ZFS_EXIT(zfsvfs);
1111 return (error);
1112
1113
1114 }
1115
1116 /* ARGSUSED */
1117 static int
1118 zfsctl_snapdir_getattr(vnode_t *vp, vattr_t *vap, int flags, cred_t *cr,
1119 caller_context_t *ct)
1120 {
1121 zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
1122 zfsctl_snapdir_t *sdp = vp->v_data;
1123
1124 ZFS_ENTER(zfsvfs);
1125 zfsctl_common_getattr(vp, vap);
1126 vap->va_nodeid = gfs_file_inode(vp);
1127 vap->va_nlink = vap->va_size = avl_numnodes(&sdp->sd_snaps) + 2;
1128 vap->va_ctime = vap->va_mtime = dmu_objset_snap_cmtime(zfsvfs->z_os);
1129 ZFS_EXIT(zfsvfs);
1130
1131 return (0);
1132 }
1133
1134 /* ARGSUSED */
1135 static void
1136 zfsctl_snapdir_inactive(vnode_t *vp, cred_t *cr, caller_context_t *ct)
1137 {
1138 zfsctl_snapdir_t *sdp = vp->v_data;
1139 void *private;
1140
1141 private = gfs_dir_inactive(vp);
1142 if (private != NULL) {
1143 ASSERT(avl_numnodes(&sdp->sd_snaps) == 0);
1144 mutex_destroy(&sdp->sd_lock);
1145 avl_destroy(&sdp->sd_snaps);
1146 kmem_free(private, sizeof (zfsctl_snapdir_t));
1147 }
1148 }
1149
1150 static const fs_operation_def_t zfsctl_tops_snapdir[] = {
1151 { VOPNAME_OPEN, { .vop_open = zfsctl_common_open } },
1152 { VOPNAME_CLOSE, { .vop_close = zfsctl_common_close } },
1153 { VOPNAME_IOCTL, { .error = fs_inval } },
1154 { VOPNAME_GETATTR, { .vop_getattr = zfsctl_snapdir_getattr } },
1155 { VOPNAME_ACCESS, { .vop_access = zfsctl_common_access } },
1156 { VOPNAME_RENAME, { .vop_rename = zfsctl_snapdir_rename } },
1157 { VOPNAME_RMDIR, { .vop_rmdir = zfsctl_snapdir_remove } },
1158 { VOPNAME_MKDIR, { .vop_mkdir = zfsctl_snapdir_mkdir } },
1159 { VOPNAME_READDIR, { .vop_readdir = gfs_vop_readdir } },
1160 { VOPNAME_LOOKUP, { .vop_lookup = zfsctl_snapdir_lookup } },
1161 { VOPNAME_SEEK, { .vop_seek = fs_seek } },
1162 { VOPNAME_INACTIVE, { .vop_inactive = zfsctl_snapdir_inactive } },
1163 { VOPNAME_FID, { .vop_fid = zfsctl_common_fid } },
1164 { NULL }
1165 };
1166
1167 static const fs_operation_def_t zfsctl_tops_shares[] = {
1168 { VOPNAME_OPEN, { .vop_open = zfsctl_common_open } },
1169 { VOPNAME_CLOSE, { .vop_close = zfsctl_common_close } },
1170 { VOPNAME_IOCTL, { .error = fs_inval } },
1171 { VOPNAME_GETATTR, { .vop_getattr = zfsctl_shares_getattr } },
1172 { VOPNAME_ACCESS, { .vop_access = zfsctl_common_access } },
1173 { VOPNAME_READDIR, { .vop_readdir = zfsctl_shares_readdir } },
1174 { VOPNAME_LOOKUP, { .vop_lookup = zfsctl_shares_lookup } },
1175 { VOPNAME_SEEK, { .vop_seek = fs_seek } },
1176 { VOPNAME_INACTIVE, { .vop_inactive = gfs_vop_inactive } },
1177 { VOPNAME_FID, { .vop_fid = zfsctl_shares_fid } },
1178 { NULL }
1179 };
1180
1181 /*
1182 * pvp is the GFS vnode '.zfs/snapshot'.
1183 *
1184 * This creates a GFS node under '.zfs/snapshot' representing each
1185 * snapshot. This newly created GFS node is what we mount snapshot
1186 * vfs_t's ontop of.
1187 */
1188 static vnode_t *
1189 zfsctl_snapshot_mknode(vnode_t *pvp, uint64_t objset)
1190 {
1191 vnode_t *vp;
1192 zfsctl_node_t *zcp;
1193
1194 vp = gfs_dir_create(sizeof (zfsctl_node_t), pvp,
1195 zfsctl_ops_snapshot, NULL, NULL, MAXNAMELEN, NULL, NULL);
1196 zcp = vp->v_data;
1197 zcp->zc_id = objset;
1198
1199 return (vp);
1200 }
1201
1202 static void
1203 zfsctl_snapshot_inactive(vnode_t *vp, cred_t *cr, caller_context_t *ct)
1204 {
1205 zfsctl_snapdir_t *sdp;
1206 zfs_snapentry_t *sep, *next;
1207 vnode_t *dvp;
1208
1209 VERIFY(gfs_dir_lookup(vp, "..", &dvp, cr, 0, NULL, NULL) == 0);
1210 sdp = dvp->v_data;
1211
1212 mutex_enter(&sdp->sd_lock);
1213
1214 if (vp->v_count > 1) {
1215 mutex_exit(&sdp->sd_lock);
1216 return;
1217 }
1218 ASSERT(!vn_ismntpt(vp));
1219
1220 sep = avl_first(&sdp->sd_snaps);
1221 while (sep != NULL) {
1222 next = AVL_NEXT(&sdp->sd_snaps, sep);
1223
1224 if (sep->se_root == vp) {
1225 avl_remove(&sdp->sd_snaps, sep);
1226 kmem_free(sep->se_name, strlen(sep->se_name) + 1);
1227 kmem_free(sep, sizeof (zfs_snapentry_t));
1228 break;
1229 }
1230 sep = next;
1231 }
1232 ASSERT(sep != NULL);
1233
1234 mutex_exit(&sdp->sd_lock);
1235 VN_RELE(dvp);
1236
1237 /*
1238 * Dispose of the vnode for the snapshot mount point.
1239 * This is safe to do because once this entry has been removed
1240 * from the AVL tree, it can't be found again, so cannot become
1241 * "active". If we lookup the same name again we will end up
1242 * creating a new vnode.
1243 */
1244 gfs_vop_inactive(vp, cr, ct);
1245 }
1246
1247
1248 /*
1249 * These VP's should never see the light of day. They should always
1250 * be covered.
1251 */
1252 static const fs_operation_def_t zfsctl_tops_snapshot[] = {
1253 VOPNAME_INACTIVE, { .vop_inactive = zfsctl_snapshot_inactive },
1254 NULL, NULL
1255 };
1256
1257 int
1258 zfsctl_lookup_objset(vfs_t *vfsp, uint64_t objsetid, zfsvfs_t **zfsvfsp)
1259 {
1260 zfsvfs_t *zfsvfs = vfsp->vfs_data;
1261 vnode_t *dvp, *vp;
1262 zfsctl_snapdir_t *sdp;
1263 zfsctl_node_t *zcp;
1264 zfs_snapentry_t *sep;
1265 int error;
1266
1267 ASSERT(zfsvfs->z_ctldir != NULL);
1268 error = zfsctl_root_lookup(zfsvfs->z_ctldir, "snapshot", &dvp,
1269 NULL, 0, NULL, kcred, NULL, NULL, NULL);
1270 if (error != 0)
1271 return (error);
1272 sdp = dvp->v_data;
1273
1274 mutex_enter(&sdp->sd_lock);
1275 sep = avl_first(&sdp->sd_snaps);
1276 while (sep != NULL) {
1277 vp = sep->se_root;
1278 zcp = vp->v_data;
1279 if (zcp->zc_id == objsetid)
1280 break;
1281
1282 sep = AVL_NEXT(&sdp->sd_snaps, sep);
1283 }
1284
1285 if (sep != NULL) {
1286 VN_HOLD(vp);
1287 /*
1288 * Return the mounted root rather than the covered mount point.
1289 * Takes the GFS vnode at .zfs/snapshot/<snapshot objsetid>
1290 * and returns the ZFS vnode mounted on top of the GFS node.
1291 * This ZFS vnode is the root of the vfs for objset 'objsetid'.
1292 */
1293 error = traverse(&vp);
1294 if (error == 0) {
1295 if (vp == sep->se_root)
1296 error = SET_ERROR(EINVAL);
1297 else
1298 *zfsvfsp = VTOZ(vp)->z_zfsvfs;
1299 }
1300 mutex_exit(&sdp->sd_lock);
1301 VN_RELE(vp);
1302 } else {
1303 error = SET_ERROR(EINVAL);
1304 mutex_exit(&sdp->sd_lock);
1305 }
1306
1307 VN_RELE(dvp);
1308
1309 return (error);
1310 }
1311
1312 /*
1313 * Unmount any snapshots for the given filesystem. This is called from
1314 * zfs_umount() - if we have a ctldir, then go through and unmount all the
1315 * snapshots.
1316 */
1317 int
1318 zfsctl_umount_snapshots(vfs_t *vfsp, int fflags, cred_t *cr)
1319 {
1320 zfsvfs_t *zfsvfs = vfsp->vfs_data;
1321 vnode_t *dvp;
1322 zfsctl_snapdir_t *sdp;
1323 zfs_snapentry_t *sep, *next;
1324 int error;
1325
1326 ASSERT(zfsvfs->z_ctldir != NULL);
1327 error = zfsctl_root_lookup(zfsvfs->z_ctldir, "snapshot", &dvp,
1328 NULL, 0, NULL, cr, NULL, NULL, NULL);
1329 if (error != 0)
1330 return (error);
1331 sdp = dvp->v_data;
1332
1333 mutex_enter(&sdp->sd_lock);
1334
1335 sep = avl_first(&sdp->sd_snaps);
1336 while (sep != NULL) {
1337 next = AVL_NEXT(&sdp->sd_snaps, sep);
1338
1339 /*
1340 * If this snapshot is not mounted, then it must
1341 * have just been unmounted by somebody else, and
1342 * will be cleaned up by zfsctl_snapdir_inactive().
1343 */
1344 if (vn_ismntpt(sep->se_root)) {
1345 avl_remove(&sdp->sd_snaps, sep);
1346 error = zfsctl_unmount_snap(sep, fflags, cr);
1347 if (error) {
1348 avl_add(&sdp->sd_snaps, sep);
1349 break;
1350 }
1351 }
1352 sep = next;
1353 }
1354
1355 mutex_exit(&sdp->sd_lock);
1356 VN_RELE(dvp);
1357
1358 return (error);
1359 }