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