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.
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.
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]
22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright (c) 2013 by Delphix. All rights reserved.
27 * ZFS control directory (a.k.a. ".zfs")
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.
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
38 * ctldir ------> snapshotdir -------> snapshot
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.
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.
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).
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.
67 #include <sys/zfs_context.h>
68 #include <sys/zfs_ctldir.h>
69 #include <sys/zfs_ioctl.h>
70 #include <sys/zfs_vfsops.h>
71 #include <sys/namei.h>
75 #include <sys/dsl_destroy.h>
76 #include <sys/dsl_deleg.h>
77 #include <sys/mount.h>
78 #include <sys/sunddi.h>
80 #include "zfs_namecheck.h"
82 typedef struct zfsctl_node {
83 gfs_dir_t zc_gfs_private;
85 timestruc_t zc_cmtime; /* ctime and mtime, always the same */
88 typedef struct zfsctl_snapdir {
89 zfsctl_node_t sd_node;
101 snapentry_compare(const void *a, const void *b)
103 const zfs_snapentry_t *sa = a;
104 const zfs_snapentry_t *sb = b;
105 int ret = strcmp(sa->se_name, sb->se_name);
116 vnodeops_t *zfsctl_ops_root;
117 vnodeops_t *zfsctl_ops_snapdir;
118 vnodeops_t *zfsctl_ops_snapshot;
119 vnodeops_t *zfsctl_ops_shares;
120 vnodeops_t *zfsctl_ops_shares_dir;
122 static const fs_operation_def_t zfsctl_tops_root[];
123 static const fs_operation_def_t zfsctl_tops_snapdir[];
124 static const fs_operation_def_t zfsctl_tops_snapshot[];
125 static const fs_operation_def_t zfsctl_tops_shares[];
127 static struct vop_vector zfsctl_ops_root;
128 static struct vop_vector zfsctl_ops_snapdir;
129 static struct vop_vector zfsctl_ops_snapshot;
130 static struct vop_vector zfsctl_ops_shares;
131 static struct vop_vector zfsctl_ops_shares_dir;
134 static vnode_t *zfsctl_mknode_snapdir(vnode_t *);
135 static vnode_t *zfsctl_mknode_shares(vnode_t *);
136 static vnode_t *zfsctl_snapshot_mknode(vnode_t *, uint64_t objset);
137 static int zfsctl_unmount_snap(zfs_snapentry_t *, int, cred_t *);
140 static gfs_opsvec_t zfsctl_opsvec[] = {
141 { ".zfs", zfsctl_tops_root, &zfsctl_ops_root },
142 { ".zfs/snapshot", zfsctl_tops_snapdir, &zfsctl_ops_snapdir },
143 { ".zfs/snapshot/vnode", zfsctl_tops_snapshot, &zfsctl_ops_snapshot },
144 { ".zfs/shares", zfsctl_tops_shares, &zfsctl_ops_shares_dir },
145 { ".zfs/shares/vnode", zfsctl_tops_shares, &zfsctl_ops_shares },
151 * Root directory elements. We only have two entries
152 * snapshot and shares.
154 static gfs_dirent_t zfsctl_root_entries[] = {
155 { "snapshot", zfsctl_mknode_snapdir, GFS_CACHE_VNODE },
156 { "shares", zfsctl_mknode_shares, GFS_CACHE_VNODE },
160 /* include . and .. in the calculation */
161 #define NROOT_ENTRIES ((sizeof (zfsctl_root_entries) / \
162 sizeof (gfs_dirent_t)) + 1)
166 * Initialize the various GFS pieces we'll need to create and manipulate .zfs
167 * directories. This is called from the ZFS init routine, and initializes the
168 * vnode ops vectors that we'll be using.
174 VERIFY(gfs_make_opsvec(zfsctl_opsvec) == 0);
183 * Remove vfsctl vnode ops
186 vn_freevnodeops(zfsctl_ops_root);
187 if (zfsctl_ops_snapdir)
188 vn_freevnodeops(zfsctl_ops_snapdir);
189 if (zfsctl_ops_snapshot)
190 vn_freevnodeops(zfsctl_ops_snapshot);
191 if (zfsctl_ops_shares)
192 vn_freevnodeops(zfsctl_ops_shares);
193 if (zfsctl_ops_shares_dir)
194 vn_freevnodeops(zfsctl_ops_shares_dir);
196 zfsctl_ops_root = NULL;
197 zfsctl_ops_snapdir = NULL;
198 zfsctl_ops_snapshot = NULL;
199 zfsctl_ops_shares = NULL;
200 zfsctl_ops_shares_dir = NULL;
205 zfsctl_is_node(vnode_t *vp)
207 return (vn_matchops(vp, zfsctl_ops_root) ||
208 vn_matchops(vp, zfsctl_ops_snapdir) ||
209 vn_matchops(vp, zfsctl_ops_snapshot) ||
210 vn_matchops(vp, zfsctl_ops_shares) ||
211 vn_matchops(vp, zfsctl_ops_shares_dir));
216 * Return the inode number associated with the 'snapshot' or
217 * 'shares' directory.
221 zfsctl_root_inode_cb(vnode_t *vp, int index)
223 zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
228 return (ZFSCTL_INO_SNAPDIR);
230 return (zfsvfs->z_shares_dir);
234 * Create the '.zfs' directory. This directory is cached as part of the VFS
235 * structure. This results in a hold on the vfs_t. The code in zfs_umount()
236 * therefore checks against a vfs_count of 2 instead of 1. This reference
237 * is removed when the ctldir is destroyed in the unmount.
240 zfsctl_create(zfsvfs_t *zfsvfs)
246 ASSERT(zfsvfs->z_ctldir == NULL);
248 vp = gfs_root_create(sizeof (zfsctl_node_t), zfsvfs->z_vfs,
249 &zfsctl_ops_root, ZFSCTL_INO_ROOT, zfsctl_root_entries,
250 zfsctl_root_inode_cb, MAXNAMELEN, NULL, NULL);
252 zcp->zc_id = ZFSCTL_INO_ROOT;
254 VERIFY(VFS_ROOT(zfsvfs->z_vfs, LK_EXCLUSIVE, &rvp) == 0);
255 VERIFY(0 == sa_lookup(VTOZ(rvp)->z_sa_hdl, SA_ZPL_CRTIME(zfsvfs),
256 &crtime, sizeof (crtime)));
257 ZFS_TIME_DECODE(&zcp->zc_cmtime, crtime);
261 * We're only faking the fact that we have a root of a filesystem for
262 * the sake of the GFS interfaces. Undo the flag manipulation it did
265 vp->v_vflag &= ~VV_ROOT;
267 zfsvfs->z_ctldir = vp;
273 * Destroy the '.zfs' directory. Only called when the filesystem is unmounted.
274 * There might still be more references if we were force unmounted, but only
275 * new zfs_inactive() calls can occur and they don't reference .zfs
278 zfsctl_destroy(zfsvfs_t *zfsvfs)
280 VN_RELE(zfsvfs->z_ctldir);
281 zfsvfs->z_ctldir = NULL;
285 * Given a root znode, retrieve the associated .zfs directory.
286 * Add a hold to the vnode and return it.
289 zfsctl_root(znode_t *zp)
291 ASSERT(zfs_has_ctldir(zp));
292 VN_HOLD(zp->z_zfsvfs->z_ctldir);
293 return (zp->z_zfsvfs->z_ctldir);
297 * Common open routine. Disallow any write access.
301 zfsctl_common_open(struct vop_open_args *ap)
303 int flags = ap->a_mode;
306 return (SET_ERROR(EACCES));
312 * Common close routine. Nothing to do here.
316 zfsctl_common_close(struct vop_close_args *ap)
322 * Common access routine. Disallow writes.
326 zfsctl_common_access(ap)
327 struct vop_access_args /* {
330 struct ucred *a_cred;
334 accmode_t accmode = ap->a_accmode;
337 if (flags & V_ACE_MASK) {
338 if (accmode & ACE_ALL_WRITE_PERMS)
339 return (SET_ERROR(EACCES));
342 if (accmode & VWRITE)
343 return (SET_ERROR(EACCES));
352 * Common getattr function. Fill in basic information.
355 zfsctl_common_getattr(vnode_t *vp, vattr_t *vap)
363 * We are a purely virtual object, so we have no
364 * blocksize or allocated blocks.
369 vap->va_fsid = vp->v_mount->mnt_stat.f_fsid.val[0];
370 vap->va_mode = S_IRUSR | S_IXUSR | S_IRGRP | S_IXGRP |
374 * We live in the now (for atime).
378 /* FreeBSD: Reset chflags(2) flags. */
384 zfsctl_common_fid(ap)
385 struct vop_fid_args /* {
390 vnode_t *vp = ap->a_vp;
391 fid_t *fidp = (void *)ap->a_fid;
392 zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
393 zfsctl_node_t *zcp = vp->v_data;
394 uint64_t object = zcp->zc_id;
401 if (fidp->fid_len < SHORT_FID_LEN) {
402 fidp->fid_len = SHORT_FID_LEN;
404 return (SET_ERROR(ENOSPC));
408 zfid = (zfid_short_t *)fidp;
410 zfid->zf_len = SHORT_FID_LEN;
412 for (i = 0; i < sizeof (zfid->zf_object); i++)
413 zfid->zf_object[i] = (uint8_t)(object >> (8 * i));
415 /* .zfs znodes always have a generation number of 0 */
416 for (i = 0; i < sizeof (zfid->zf_gen); i++)
426 zfsctl_shares_fid(ap)
427 struct vop_fid_args /* {
432 vnode_t *vp = ap->a_vp;
433 fid_t *fidp = (void *)ap->a_fid;
434 zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
440 if (zfsvfs->z_shares_dir == 0) {
442 return (SET_ERROR(ENOTSUP));
445 if ((error = zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp)) == 0) {
446 error = VOP_FID(ZTOV(dzp), fidp);
455 zfsctl_common_reclaim(ap)
456 struct vop_reclaim_args /* {
461 vnode_t *vp = ap->a_vp;
464 * Destroy the vm object and flush associated pages.
466 vnode_destroy_vobject(vp);
474 * .zfs inode namespace
476 * We need to generate unique inode numbers for all files and directories
477 * within the .zfs pseudo-filesystem. We use the following scheme:
482 * .zfs/snapshot/<snap> objectid(snap)
485 #define ZFSCTL_INO_SNAP(id) (id)
488 * Get root directory attributes.
492 zfsctl_root_getattr(ap)
493 struct vop_getattr_args /* {
496 struct ucred *a_cred;
499 struct vnode *vp = ap->a_vp;
500 struct vattr *vap = ap->a_vap;
501 zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
502 zfsctl_node_t *zcp = vp->v_data;
505 vap->va_nodeid = ZFSCTL_INO_ROOT;
506 vap->va_nlink = vap->va_size = NROOT_ENTRIES;
507 vap->va_mtime = vap->va_ctime = zcp->zc_cmtime;
508 vap->va_birthtime = vap->va_ctime;
510 zfsctl_common_getattr(vp, vap);
517 * Special case the handling of "..".
521 zfsctl_root_lookup(vnode_t *dvp, char *nm, vnode_t **vpp, pathname_t *pnp,
522 int flags, vnode_t *rdir, cred_t *cr, caller_context_t *ct,
523 int *direntflags, pathname_t *realpnp)
525 zfsvfs_t *zfsvfs = dvp->v_vfsp->vfs_data;
529 * No extended attributes allowed under .zfs
531 if (flags & LOOKUP_XATTR)
532 return (SET_ERROR(EINVAL));
536 if (strcmp(nm, "..") == 0) {
538 err = VFS_ROOT(dvp->v_vfsp, LK_EXCLUSIVE, vpp);
541 * NB: can not use VFS_ROOT here as it would acquire
542 * the vnode lock of the parent (root) vnode while
543 * holding the child's (.zfs) lock.
547 err = zfs_zget(zfsvfs, zfsvfs->z_root, &rootzp);
552 err = gfs_vop_lookup(dvp, nm, vpp, pnp, flags, rdir,
553 cr, ct, direntflags, realpnp);
563 zfsctl_pathconf(vnode_t *vp, int cmd, ulong_t *valp, cred_t *cr,
564 caller_context_t *ct)
567 * We only care about ACL_ENABLED so that libsec can
568 * display ACL correctly and not default to POSIX draft.
570 if (cmd == _PC_ACL_ENABLED) {
571 *valp = _ACL_ACE_ENABLED;
575 return (fs_pathconf(vp, cmd, valp, cr, ct));
580 static const fs_operation_def_t zfsctl_tops_root[] = {
581 { VOPNAME_OPEN, { .vop_open = zfsctl_common_open } },
582 { VOPNAME_CLOSE, { .vop_close = zfsctl_common_close } },
583 { VOPNAME_IOCTL, { .error = fs_inval } },
584 { VOPNAME_GETATTR, { .vop_getattr = zfsctl_root_getattr } },
585 { VOPNAME_ACCESS, { .vop_access = zfsctl_common_access } },
586 { VOPNAME_READDIR, { .vop_readdir = gfs_vop_readdir } },
587 { VOPNAME_LOOKUP, { .vop_lookup = zfsctl_root_lookup } },
588 { VOPNAME_SEEK, { .vop_seek = fs_seek } },
589 { VOPNAME_INACTIVE, { .vop_inactive = gfs_vop_inactive } },
590 { VOPNAME_PATHCONF, { .vop_pathconf = zfsctl_pathconf } },
591 { VOPNAME_FID, { .vop_fid = zfsctl_common_fid } },
597 * Special case the handling of "..".
601 zfsctl_freebsd_root_lookup(ap)
602 struct vop_lookup_args /* {
604 struct vnode **a_vpp;
605 struct componentname *a_cnp;
608 vnode_t *dvp = ap->a_dvp;
609 vnode_t **vpp = ap->a_vpp;
610 cred_t *cr = ap->a_cnp->cn_cred;
611 int flags = ap->a_cnp->cn_flags;
612 int lkflags = ap->a_cnp->cn_lkflags;
613 int nameiop = ap->a_cnp->cn_nameiop;
614 char nm[NAME_MAX + 1];
617 if ((flags & ISLASTCN) && (nameiop == RENAME || nameiop == CREATE))
620 ASSERT(ap->a_cnp->cn_namelen < sizeof(nm));
621 strlcpy(nm, ap->a_cnp->cn_nameptr, ap->a_cnp->cn_namelen + 1);
623 err = zfsctl_root_lookup(dvp, nm, vpp, NULL, 0, NULL, cr, NULL, NULL, NULL);
624 if (err == 0 && (nm[0] != '.' || nm[1] != '\0')) {
625 if (flags & ISDOTDOT)
627 err = vn_lock(*vpp, lkflags);
632 if (flags & ISDOTDOT)
633 vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY);
639 static struct vop_vector zfsctl_ops_root = {
640 .vop_default = &default_vnodeops,
641 .vop_open = zfsctl_common_open,
642 .vop_close = zfsctl_common_close,
643 .vop_ioctl = VOP_EINVAL,
644 .vop_getattr = zfsctl_root_getattr,
645 .vop_access = zfsctl_common_access,
646 .vop_readdir = gfs_vop_readdir,
647 .vop_lookup = zfsctl_freebsd_root_lookup,
648 .vop_inactive = gfs_vop_inactive,
649 .vop_reclaim = zfsctl_common_reclaim,
651 .vop_pathconf = zfsctl_pathconf,
653 .vop_fid = zfsctl_common_fid,
657 * Gets the full dataset name that corresponds to the given snapshot name
659 * zfsctl_snapshot_zname("snap1") -> "mypool/myfs@snap1"
662 zfsctl_snapshot_zname(vnode_t *vp, const char *name, int len, char *zname)
664 objset_t *os = ((zfsvfs_t *)((vp)->v_vfsp->vfs_data))->z_os;
666 if (zfs_component_namecheck(name, NULL, NULL) != 0)
667 return (SET_ERROR(EILSEQ));
668 dmu_objset_name(os, zname);
669 if (strlen(zname) + 1 + strlen(name) >= len)
670 return (SET_ERROR(ENAMETOOLONG));
671 (void) strcat(zname, "@");
672 (void) strcat(zname, name);
677 zfsctl_unmount_snap(zfs_snapentry_t *sep, int fflags, cred_t *cr)
679 vnode_t *svp = sep->se_root;
682 ASSERT(vn_ismntpt(svp));
684 /* this will be dropped by dounmount() */
685 if ((error = vn_vfswlock(svp)) != 0)
690 error = dounmount(vn_mountedvfs(svp), fflags, cr);
697 * We can't use VN_RELE(), as that will try to invoke
698 * zfsctl_snapdir_inactive(), which would cause us to destroy
699 * the sd_lock mutex held by our caller.
701 ASSERT(svp->v_count == 1);
702 gfs_vop_inactive(svp, cr, NULL);
704 kmem_free(sep->se_name, strlen(sep->se_name) + 1);
705 kmem_free(sep, sizeof (zfs_snapentry_t));
709 return (dounmount(vn_mountedvfs(svp), fflags, curthread));
715 zfsctl_rename_snap(zfsctl_snapdir_t *sdp, zfs_snapentry_t *sep, const char *nm)
720 char newpath[MAXNAMELEN];
723 ASSERT(MUTEX_HELD(&sdp->sd_lock));
726 vfsp = vn_mountedvfs(sep->se_root);
727 ASSERT(vfsp != NULL);
732 * Change the name in the AVL tree.
734 avl_remove(&sdp->sd_snaps, sep);
735 kmem_free(sep->se_name, strlen(sep->se_name) + 1);
736 sep->se_name = kmem_alloc(strlen(nm) + 1, KM_SLEEP);
737 (void) strcpy(sep->se_name, nm);
738 VERIFY(avl_find(&sdp->sd_snaps, sep, &where) == NULL);
739 avl_insert(&sdp->sd_snaps, sep, where);
742 * Change the current mountpoint info:
743 * - update the tail of the mntpoint path
744 * - update the tail of the resource path
746 pathref = vfs_getmntpoint(vfsp);
747 (void) strncpy(newpath, refstr_value(pathref), sizeof (newpath));
748 VERIFY((tail = strrchr(newpath, '/')) != NULL);
750 ASSERT3U(strlen(newpath) + strlen(nm), <, sizeof (newpath));
751 (void) strcat(newpath, nm);
752 refstr_rele(pathref);
753 vfs_setmntpoint(vfsp, newpath, 0);
755 pathref = vfs_getresource(vfsp);
756 (void) strncpy(newpath, refstr_value(pathref), sizeof (newpath));
757 VERIFY((tail = strrchr(newpath, '@')) != NULL);
759 ASSERT3U(strlen(newpath) + strlen(nm), <, sizeof (newpath));
760 (void) strcat(newpath, nm);
761 refstr_rele(pathref);
762 vfs_setresource(vfsp, newpath, 0);
771 zfsctl_snapdir_rename(vnode_t *sdvp, char *snm, vnode_t *tdvp, char *tnm,
772 cred_t *cr, caller_context_t *ct, int flags)
774 zfsctl_snapdir_t *sdp = sdvp->v_data;
775 zfs_snapentry_t search, *sep;
778 char from[MAXNAMELEN], to[MAXNAMELEN];
779 char real[MAXNAMELEN], fsname[MAXNAMELEN];
782 zfsvfs = sdvp->v_vfsp->vfs_data;
785 if ((flags & FIGNORECASE) || zfsvfs->z_case == ZFS_CASE_INSENSITIVE) {
786 err = dmu_snapshot_realname(zfsvfs->z_os, snm, real,
790 } else if (err != ENOTSUP) {
798 dmu_objset_name(zfsvfs->z_os, fsname);
800 err = zfsctl_snapshot_zname(sdvp, snm, MAXNAMELEN, from);
802 err = zfsctl_snapshot_zname(tdvp, tnm, MAXNAMELEN, to);
804 err = zfs_secpolicy_rename_perms(from, to, cr);
809 * Cannot move snapshots out of the snapdir.
812 return (SET_ERROR(EINVAL));
814 if (strcmp(snm, tnm) == 0)
817 mutex_enter(&sdp->sd_lock);
819 search.se_name = (char *)snm;
820 if ((sep = avl_find(&sdp->sd_snaps, &search, &where)) == NULL) {
821 mutex_exit(&sdp->sd_lock);
822 return (SET_ERROR(ENOENT));
825 err = dsl_dataset_rename_snapshot(fsname, snm, tnm, 0);
827 zfsctl_rename_snap(sdp, sep, tnm);
829 mutex_exit(&sdp->sd_lock);
838 zfsctl_snapdir_remove(vnode_t *dvp, char *name, vnode_t *cwd, cred_t *cr,
839 caller_context_t *ct, int flags)
841 zfsctl_snapdir_t *sdp = dvp->v_data;
842 zfs_snapentry_t *sep;
843 zfs_snapentry_t search;
845 char snapname[MAXNAMELEN];
846 char real[MAXNAMELEN];
849 zfsvfs = dvp->v_vfsp->vfs_data;
852 if ((flags & FIGNORECASE) || zfsvfs->z_case == ZFS_CASE_INSENSITIVE) {
854 err = dmu_snapshot_realname(zfsvfs->z_os, name, real,
858 } else if (err != ENOTSUP) {
866 err = zfsctl_snapshot_zname(dvp, name, MAXNAMELEN, snapname);
868 err = zfs_secpolicy_destroy_perms(snapname, cr);
872 mutex_enter(&sdp->sd_lock);
874 search.se_name = name;
875 sep = avl_find(&sdp->sd_snaps, &search, NULL);
877 avl_remove(&sdp->sd_snaps, sep);
878 err = zfsctl_unmount_snap(sep, MS_FORCE, cr);
880 avl_add(&sdp->sd_snaps, sep);
882 err = dsl_destroy_snapshot(snapname, B_FALSE);
884 err = SET_ERROR(ENOENT);
887 mutex_exit(&sdp->sd_lock);
894 * This creates a snapshot under '.zfs/snapshot'.
898 zfsctl_snapdir_mkdir(vnode_t *dvp, char *dirname, vattr_t *vap, vnode_t **vpp,
899 cred_t *cr, caller_context_t *cc, int flags, vsecattr_t *vsecp)
901 zfsvfs_t *zfsvfs = dvp->v_vfsp->vfs_data;
902 char name[MAXNAMELEN];
904 static enum symfollow follow = NO_FOLLOW;
905 static enum uio_seg seg = UIO_SYSSPACE;
907 if (zfs_component_namecheck(dirname, NULL, NULL) != 0)
908 return (SET_ERROR(EILSEQ));
910 dmu_objset_name(zfsvfs->z_os, name);
914 err = zfs_secpolicy_snapshot_perms(name, cr);
919 err = dmu_objset_snapshot_one(name, dirname);
922 err = lookupnameat(dirname, seg, follow, NULL, vpp, dvp);
929 zfsctl_freebsd_snapdir_mkdir(ap)
930 struct vop_mkdir_args /* {
932 struct vnode **a_vpp;
933 struct componentname *a_cnp;
938 ASSERT(ap->a_cnp->cn_flags & SAVENAME);
940 return (zfsctl_snapdir_mkdir(ap->a_dvp, ap->a_cnp->cn_nameptr, NULL,
941 ap->a_vpp, ap->a_cnp->cn_cred, NULL, 0, NULL));
945 * Lookup entry point for the 'snapshot' directory. Try to open the
946 * snapshot if it exist, creating the pseudo filesystem vnode as necessary.
947 * Perform a mount of the associated dataset on top of the vnode.
951 zfsctl_snapdir_lookup(ap)
952 struct vop_lookup_args /* {
954 struct vnode **a_vpp;
955 struct componentname *a_cnp;
958 vnode_t *dvp = ap->a_dvp;
959 vnode_t **vpp = ap->a_vpp;
960 struct componentname *cnp = ap->a_cnp;
961 char nm[NAME_MAX + 1];
962 zfsctl_snapdir_t *sdp = dvp->v_data;
964 char snapname[MAXNAMELEN];
965 char real[MAXNAMELEN];
967 zfs_snapentry_t *sep, search;
968 size_t mountpoint_len;
970 zfsvfs_t *zfsvfs = dvp->v_vfsp->vfs_data;
975 * No extended attributes allowed under .zfs
977 if (flags & LOOKUP_XATTR)
978 return (SET_ERROR(EINVAL));
979 ASSERT(ap->a_cnp->cn_namelen < sizeof(nm));
980 strlcpy(nm, ap->a_cnp->cn_nameptr, ap->a_cnp->cn_namelen + 1);
982 ASSERT(dvp->v_type == VDIR);
987 * If we get a recursive call, that means we got called
988 * from the domount() code while it was trying to look up the
989 * spec (which looks like a local path for zfs). We need to
990 * add some flag to domount() to tell it not to do this lookup.
992 if (MUTEX_HELD(&sdp->sd_lock))
993 return (SET_ERROR(ENOENT));
997 if (gfs_lookup_dot(vpp, dvp, zfsvfs->z_ctldir, nm) == 0) {
998 if (nm[0] == '.' && nm[1] == '.' && nm[2] =='\0') {
1000 VERIFY0(vn_lock(*vpp, LK_EXCLUSIVE));
1001 VERIFY0(vn_lock(dvp, LK_EXCLUSIVE));
1007 if (flags & FIGNORECASE) {
1008 boolean_t conflict = B_FALSE;
1010 err = dmu_snapshot_realname(zfsvfs->z_os, nm, real,
1011 MAXNAMELEN, &conflict);
1013 strlcpy(nm, real, sizeof(nm));
1014 } else if (err != ENOTSUP) {
1020 (void) strlcpy(realpnp->pn_buf, nm,
1021 realpnp->pn_bufsize);
1022 if (conflict && direntflags)
1023 *direntflags = ED_CASE_CONFLICT;
1028 mutex_enter(&sdp->sd_lock);
1029 search.se_name = (char *)nm;
1030 if ((sep = avl_find(&sdp->sd_snaps, &search, &where)) != NULL) {
1031 *vpp = sep->se_root;
1033 err = traverse(vpp, LK_EXCLUSIVE | LK_RETRY);
1036 } else if (*vpp == sep->se_root) {
1038 * The snapshot was unmounted behind our backs,
1039 * try to remount it.
1041 VERIFY(zfsctl_snapshot_zname(dvp, nm, MAXNAMELEN, snapname) == 0);
1044 mutex_exit(&sdp->sd_lock);
1050 * The requested snapshot is not currently mounted, look it up.
1052 err = zfsctl_snapshot_zname(dvp, nm, MAXNAMELEN, snapname);
1054 mutex_exit(&sdp->sd_lock);
1057 * handle "ls *" or "?" in a graceful manner,
1058 * forcing EILSEQ to ENOENT.
1059 * Since shell ultimately passes "*" or "?" as name to lookup
1061 return (err == EILSEQ ? ENOENT : err);
1063 if (dmu_objset_hold(snapname, FTAG, &snap) != 0) {
1064 mutex_exit(&sdp->sd_lock);
1067 return (SET_ERROR(ENOENT));
1068 #else /* !illumos */
1069 /* Translate errors and add SAVENAME when needed. */
1070 if ((cnp->cn_flags & ISLASTCN) && cnp->cn_nameiop == CREATE) {
1072 cnp->cn_flags |= SAVENAME;
1074 err = SET_ERROR(ENOENT);
1078 #endif /* !illumos */
1081 sep = kmem_alloc(sizeof (zfs_snapentry_t), KM_SLEEP);
1082 sep->se_name = kmem_alloc(strlen(nm) + 1, KM_SLEEP);
1083 (void) strcpy(sep->se_name, nm);
1084 *vpp = sep->se_root = zfsctl_snapshot_mknode(dvp, dmu_objset_id(snap));
1085 avl_insert(&sdp->sd_snaps, sep, where);
1087 dmu_objset_rele(snap, FTAG);
1089 mountpoint_len = strlen(dvp->v_vfsp->mnt_stat.f_mntonname) +
1090 strlen("/" ZFS_CTLDIR_NAME "/snapshot/") + strlen(nm) + 1;
1091 mountpoint = kmem_alloc(mountpoint_len, KM_SLEEP);
1092 (void) snprintf(mountpoint, mountpoint_len,
1093 "%s/" ZFS_CTLDIR_NAME "/snapshot/%s",
1094 dvp->v_vfsp->mnt_stat.f_mntonname, nm);
1095 mutex_exit(&sdp->sd_lock);
1098 * The vnode may get reclaimed between dropping sd_lock and
1099 * getting the vnode lock.
1101 err = vn_lock(*vpp, LK_EXCLUSIVE);
1105 err = mount_snapshot(curthread, vpp, "zfs", mountpoint, snapname, 0);
1106 kmem_free(mountpoint, mountpoint_len);
1109 * Fix up the root vnode mounted on .zfs/snapshot/<snapname>.
1111 * This is where we lie about our v_vfsp in order to
1112 * make .zfs/snapshot/<snapname> accessible over NFS
1113 * without requiring manual mounts of <snapname>.
1115 ASSERT(VTOZ(*vpp)->z_zfsvfs != zfsvfs);
1116 VTOZ(*vpp)->z_zfsvfs->z_parent = zfsvfs;
1122 * If we had an error, drop our hold on the vnode and
1123 * zfsctl_snapshot_inactive() will clean up.
1138 zfsctl_shares_lookup(ap)
1139 struct vop_lookup_args /* {
1140 struct vnode *a_dvp;
1141 struct vnode **a_vpp;
1142 struct componentname *a_cnp;
1145 vnode_t *dvp = ap->a_dvp;
1146 vnode_t **vpp = ap->a_vpp;
1147 struct componentname *cnp = ap->a_cnp;
1148 zfsvfs_t *zfsvfs = dvp->v_vfsp->vfs_data;
1149 char nm[NAME_MAX + 1];
1155 ASSERT(cnp->cn_namelen < sizeof(nm));
1156 strlcpy(nm, cnp->cn_nameptr, cnp->cn_namelen + 1);
1158 if (gfs_lookup_dot(vpp, dvp, zfsvfs->z_ctldir, nm) == 0) {
1159 if (nm[0] == '.' && nm[1] == '.' && nm[2] =='\0') {
1161 VERIFY0(vn_lock(*vpp, LK_EXCLUSIVE));
1162 VERIFY0(vn_lock(dvp, LK_EXCLUSIVE));
1168 if (zfsvfs->z_shares_dir == 0) {
1170 return (SET_ERROR(ENOTSUP));
1172 if ((error = zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp)) == 0)
1173 error = VOP_LOOKUP(ZTOV(dzp), vpp, cnp);
1183 zfsctl_snapdir_readdir_cb(vnode_t *vp, void *dp, int *eofp,
1184 offset_t *offp, offset_t *nextp, void *data, int flags)
1186 zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
1187 char snapname[MAXNAMELEN];
1188 uint64_t id, cookie;
1189 boolean_t case_conflict;
1195 dsl_pool_config_enter(dmu_objset_pool(zfsvfs->z_os), FTAG);
1196 error = dmu_snapshot_list_next(zfsvfs->z_os, MAXNAMELEN, snapname, &id,
1197 &cookie, &case_conflict);
1198 dsl_pool_config_exit(dmu_objset_pool(zfsvfs->z_os), FTAG);
1201 if (error == ENOENT) {
1208 if (flags & V_RDDIR_ENTFLAGS) {
1209 edirent_t *eodp = dp;
1211 (void) strcpy(eodp->ed_name, snapname);
1212 eodp->ed_ino = ZFSCTL_INO_SNAP(id);
1213 eodp->ed_eflags = case_conflict ? ED_CASE_CONFLICT : 0;
1215 struct dirent64 *odp = dp;
1217 (void) strcpy(odp->d_name, snapname);
1218 odp->d_ino = ZFSCTL_INO_SNAP(id);
1229 zfsctl_shares_readdir(ap)
1230 struct vop_readdir_args /* {
1233 struct ucred *a_cred;
1239 vnode_t *vp = ap->a_vp;
1240 uio_t *uiop = ap->a_uio;
1241 cred_t *cr = ap->a_cred;
1242 int *eofp = ap->a_eofflag;
1243 zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
1249 if (zfsvfs->z_shares_dir == 0) {
1251 return (SET_ERROR(ENOTSUP));
1253 if ((error = zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp)) == 0) {
1254 vn_lock(ZTOV(dzp), LK_SHARED | LK_RETRY);
1255 error = VOP_READDIR(ZTOV(dzp), uiop, cr, eofp, ap->a_ncookies, ap->a_cookies);
1256 VN_URELE(ZTOV(dzp));
1259 error = SET_ERROR(ENOENT);
1267 * pvp is the '.zfs' directory (zfsctl_node_t).
1269 * Creates vp, which is '.zfs/snapshot' (zfsctl_snapdir_t).
1271 * This function is the callback to create a GFS vnode for '.zfs/snapshot'
1272 * when a lookup is performed on .zfs for "snapshot".
1275 zfsctl_mknode_snapdir(vnode_t *pvp)
1278 zfsctl_snapdir_t *sdp;
1280 vp = gfs_dir_create(sizeof (zfsctl_snapdir_t), pvp, pvp->v_vfsp,
1281 &zfsctl_ops_snapdir, NULL, NULL, MAXNAMELEN,
1282 zfsctl_snapdir_readdir_cb, NULL);
1284 sdp->sd_node.zc_id = ZFSCTL_INO_SNAPDIR;
1285 sdp->sd_node.zc_cmtime = ((zfsctl_node_t *)pvp->v_data)->zc_cmtime;
1286 mutex_init(&sdp->sd_lock, NULL, MUTEX_DEFAULT, NULL);
1287 avl_create(&sdp->sd_snaps, snapentry_compare,
1288 sizeof (zfs_snapentry_t), offsetof(zfs_snapentry_t, se_node));
1294 zfsctl_mknode_shares(vnode_t *pvp)
1299 vp = gfs_dir_create(sizeof (zfsctl_node_t), pvp, pvp->v_vfsp,
1300 &zfsctl_ops_shares, NULL, NULL, MAXNAMELEN,
1303 sdp->zc_cmtime = ((zfsctl_node_t *)pvp->v_data)->zc_cmtime;
1311 zfsctl_shares_getattr(ap)
1312 struct vop_getattr_args /* {
1314 struct vattr *a_vap;
1315 struct ucred *a_cred;
1316 struct thread *a_td;
1319 vnode_t *vp = ap->a_vp;
1320 vattr_t *vap = ap->a_vap;
1321 cred_t *cr = ap->a_cred;
1322 zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
1327 if (zfsvfs->z_shares_dir == 0) {
1329 return (SET_ERROR(ENOTSUP));
1331 if ((error = zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp)) == 0) {
1332 vn_lock(ZTOV(dzp), LK_SHARED | LK_RETRY);
1333 error = VOP_GETATTR(ZTOV(dzp), vap, cr);
1334 VN_URELE(ZTOV(dzp));
1344 zfsctl_snapdir_getattr(ap)
1345 struct vop_getattr_args /* {
1347 struct vattr *a_vap;
1348 struct ucred *a_cred;
1351 vnode_t *vp = ap->a_vp;
1352 vattr_t *vap = ap->a_vap;
1353 zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
1354 zfsctl_snapdir_t *sdp = vp->v_data;
1357 zfsctl_common_getattr(vp, vap);
1358 vap->va_nodeid = gfs_file_inode(vp);
1359 vap->va_nlink = vap->va_size = avl_numnodes(&sdp->sd_snaps) + 2;
1360 vap->va_ctime = vap->va_mtime = dmu_objset_snap_cmtime(zfsvfs->z_os);
1361 vap->va_birthtime = vap->va_ctime;
1369 zfsctl_snapdir_inactive(ap)
1370 struct vop_inactive_args /* {
1372 struct thread *a_td;
1375 vnode_t *vp = ap->a_vp;
1376 zfsctl_snapdir_t *sdp = vp->v_data;
1377 zfs_snapentry_t *sep;
1380 * On forced unmount we have to free snapshots from here.
1382 mutex_enter(&sdp->sd_lock);
1383 while ((sep = avl_first(&sdp->sd_snaps)) != NULL) {
1384 avl_remove(&sdp->sd_snaps, sep);
1385 kmem_free(sep->se_name, strlen(sep->se_name) + 1);
1386 kmem_free(sep, sizeof (zfs_snapentry_t));
1388 mutex_exit(&sdp->sd_lock);
1389 gfs_dir_inactive(vp);
1390 ASSERT(avl_numnodes(&sdp->sd_snaps) == 0);
1391 mutex_destroy(&sdp->sd_lock);
1392 avl_destroy(&sdp->sd_snaps);
1393 kmem_free(sdp, sizeof (zfsctl_snapdir_t));
1399 static const fs_operation_def_t zfsctl_tops_snapdir[] = {
1400 { VOPNAME_OPEN, { .vop_open = zfsctl_common_open } },
1401 { VOPNAME_CLOSE, { .vop_close = zfsctl_common_close } },
1402 { VOPNAME_IOCTL, { .error = fs_inval } },
1403 { VOPNAME_GETATTR, { .vop_getattr = zfsctl_snapdir_getattr } },
1404 { VOPNAME_ACCESS, { .vop_access = zfsctl_common_access } },
1405 { VOPNAME_RENAME, { .vop_rename = zfsctl_snapdir_rename } },
1406 { VOPNAME_RMDIR, { .vop_rmdir = zfsctl_snapdir_remove } },
1407 { VOPNAME_MKDIR, { .vop_mkdir = zfsctl_snapdir_mkdir } },
1408 { VOPNAME_READDIR, { .vop_readdir = gfs_vop_readdir } },
1409 { VOPNAME_LOOKUP, { .vop_lookup = zfsctl_snapdir_lookup } },
1410 { VOPNAME_SEEK, { .vop_seek = fs_seek } },
1411 { VOPNAME_INACTIVE, { .vop_inactive = zfsctl_snapdir_inactive } },
1412 { VOPNAME_FID, { .vop_fid = zfsctl_common_fid } },
1416 static const fs_operation_def_t zfsctl_tops_shares[] = {
1417 { VOPNAME_OPEN, { .vop_open = zfsctl_common_open } },
1418 { VOPNAME_CLOSE, { .vop_close = zfsctl_common_close } },
1419 { VOPNAME_IOCTL, { .error = fs_inval } },
1420 { VOPNAME_GETATTR, { .vop_getattr = zfsctl_shares_getattr } },
1421 { VOPNAME_ACCESS, { .vop_access = zfsctl_common_access } },
1422 { VOPNAME_READDIR, { .vop_readdir = zfsctl_shares_readdir } },
1423 { VOPNAME_LOOKUP, { .vop_lookup = zfsctl_shares_lookup } },
1424 { VOPNAME_SEEK, { .vop_seek = fs_seek } },
1425 { VOPNAME_INACTIVE, { .vop_inactive = gfs_vop_inactive } },
1426 { VOPNAME_FID, { .vop_fid = zfsctl_shares_fid } },
1430 static struct vop_vector zfsctl_ops_snapdir = {
1431 .vop_default = &default_vnodeops,
1432 .vop_open = zfsctl_common_open,
1433 .vop_close = zfsctl_common_close,
1434 .vop_ioctl = VOP_EINVAL,
1435 .vop_getattr = zfsctl_snapdir_getattr,
1436 .vop_access = zfsctl_common_access,
1437 .vop_mkdir = zfsctl_freebsd_snapdir_mkdir,
1438 .vop_readdir = gfs_vop_readdir,
1439 .vop_lookup = zfsctl_snapdir_lookup,
1440 .vop_inactive = zfsctl_snapdir_inactive,
1441 .vop_reclaim = zfsctl_common_reclaim,
1442 .vop_fid = zfsctl_common_fid,
1445 static struct vop_vector zfsctl_ops_shares = {
1446 .vop_default = &default_vnodeops,
1447 .vop_open = zfsctl_common_open,
1448 .vop_close = zfsctl_common_close,
1449 .vop_ioctl = VOP_EINVAL,
1450 .vop_getattr = zfsctl_shares_getattr,
1451 .vop_access = zfsctl_common_access,
1452 .vop_readdir = zfsctl_shares_readdir,
1453 .vop_lookup = zfsctl_shares_lookup,
1454 .vop_inactive = gfs_vop_inactive,
1455 .vop_reclaim = zfsctl_common_reclaim,
1456 .vop_fid = zfsctl_shares_fid,
1461 * pvp is the GFS vnode '.zfs/snapshot'.
1463 * This creates a GFS node under '.zfs/snapshot' representing each
1464 * snapshot. This newly created GFS node is what we mount snapshot
1468 zfsctl_snapshot_mknode(vnode_t *pvp, uint64_t objset)
1473 vp = gfs_dir_create(sizeof (zfsctl_node_t), pvp, pvp->v_vfsp,
1474 &zfsctl_ops_snapshot, NULL, NULL, MAXNAMELEN, NULL, NULL);
1476 zcp->zc_id = objset;
1483 zfsctl_snapshot_inactive(ap)
1484 struct vop_inactive_args /* {
1486 struct thread *a_td;
1489 vnode_t *vp = ap->a_vp;
1490 cred_t *cr = ap->a_td->td_ucred;
1491 struct vop_inactive_args iap;
1492 zfsctl_snapdir_t *sdp;
1493 zfs_snapentry_t *sep, *next;
1497 if (vp->v_count > 0)
1500 VERIFY(gfs_dir_lookup(vp, "..", &dvp, cr, 0, NULL, NULL) == 0);
1503 if (!(locked = MUTEX_HELD(&sdp->sd_lock)))
1504 mutex_enter(&sdp->sd_lock);
1506 ASSERT(!vn_ismntpt(vp));
1508 sep = avl_first(&sdp->sd_snaps);
1509 while (sep != NULL) {
1510 next = AVL_NEXT(&sdp->sd_snaps, sep);
1512 if (sep->se_root == vp) {
1513 avl_remove(&sdp->sd_snaps, sep);
1514 kmem_free(sep->se_name, strlen(sep->se_name) + 1);
1515 kmem_free(sep, sizeof (zfs_snapentry_t));
1520 ASSERT(sep != NULL);
1523 mutex_exit(&sdp->sd_lock);
1528 * Dispose of the vnode for the snapshot mount point.
1529 * This is safe to do because once this entry has been removed
1530 * from the AVL tree, it can't be found again, so cannot become
1531 * "active". If we lookup the same name again we will end up
1532 * creating a new vnode.
1535 return (gfs_vop_inactive(&iap));
1539 zfsctl_snapshot_vptocnp(struct vop_vptocnp_args *ap)
1541 zfsvfs_t *zfsvfs = ap->a_vp->v_vfsp->vfs_data;
1543 zfsctl_snapdir_t *sdp;
1544 zfs_snapentry_t *sep;
1547 ASSERT(zfsvfs->z_ctldir != NULL);
1548 error = zfsctl_root_lookup(zfsvfs->z_ctldir, "snapshot", &dvp,
1549 NULL, 0, NULL, kcred, NULL, NULL, NULL);
1554 mutex_enter(&sdp->sd_lock);
1555 sep = avl_first(&sdp->sd_snaps);
1556 while (sep != NULL) {
1560 sep = AVL_NEXT(&sdp->sd_snaps, sep);
1563 mutex_exit(&sdp->sd_lock);
1568 len = strlen(sep->se_name);
1569 *ap->a_buflen -= len;
1570 bcopy(sep->se_name, ap->a_buf + *ap->a_buflen, len);
1571 mutex_exit(&sdp->sd_lock);
1581 * These VP's should never see the light of day. They should always
1584 static struct vop_vector zfsctl_ops_snapshot = {
1585 .vop_default = &default_vnodeops,
1586 .vop_inactive = zfsctl_snapshot_inactive,
1587 .vop_reclaim = zfsctl_common_reclaim,
1588 .vop_vptocnp = zfsctl_snapshot_vptocnp,
1592 zfsctl_lookup_objset(vfs_t *vfsp, uint64_t objsetid, zfsvfs_t **zfsvfsp)
1594 zfsvfs_t *zfsvfs = vfsp->vfs_data;
1596 zfsctl_snapdir_t *sdp;
1598 zfs_snapentry_t *sep;
1601 ASSERT(zfsvfs->z_ctldir != NULL);
1602 error = zfsctl_root_lookup(zfsvfs->z_ctldir, "snapshot", &dvp,
1603 NULL, 0, NULL, kcred, NULL, NULL, NULL);
1608 mutex_enter(&sdp->sd_lock);
1609 sep = avl_first(&sdp->sd_snaps);
1610 while (sep != NULL) {
1613 if (zcp->zc_id == objsetid)
1616 sep = AVL_NEXT(&sdp->sd_snaps, sep);
1622 * Return the mounted root rather than the covered mount point.
1623 * Takes the GFS vnode at .zfs/snapshot/<snapshot objsetid>
1624 * and returns the ZFS vnode mounted on top of the GFS node.
1625 * This ZFS vnode is the root of the vfs for objset 'objsetid'.
1627 error = traverse(&vp, LK_SHARED | LK_RETRY);
1629 if (vp == sep->se_root) {
1630 VN_RELE(vp); /* release covered vp */
1631 error = SET_ERROR(EINVAL);
1633 *zfsvfsp = VTOZ(vp)->z_zfsvfs;
1634 VN_URELE(vp); /* put snapshot's root vp */
1637 mutex_exit(&sdp->sd_lock);
1639 error = SET_ERROR(EINVAL);
1640 mutex_exit(&sdp->sd_lock);
1649 * Unmount any snapshots for the given filesystem. This is called from
1650 * zfs_umount() - if we have a ctldir, then go through and unmount all the
1654 zfsctl_umount_snapshots(vfs_t *vfsp, int fflags, cred_t *cr)
1656 zfsvfs_t *zfsvfs = vfsp->vfs_data;
1658 zfsctl_snapdir_t *sdp;
1659 zfs_snapentry_t *sep, *next;
1662 ASSERT(zfsvfs->z_ctldir != NULL);
1663 error = zfsctl_root_lookup(zfsvfs->z_ctldir, "snapshot", &dvp,
1664 NULL, 0, NULL, cr, NULL, NULL, NULL);
1669 mutex_enter(&sdp->sd_lock);
1671 sep = avl_first(&sdp->sd_snaps);
1672 while (sep != NULL) {
1673 next = AVL_NEXT(&sdp->sd_snaps, sep);
1676 * If this snapshot is not mounted, then it must
1677 * have just been unmounted by somebody else, and
1678 * will be cleaned up by zfsctl_snapdir_inactive().
1680 if (vn_ismntpt(sep->se_root)) {
1681 error = zfsctl_unmount_snap(sep, fflags, cr);
1686 * Before reinserting snapshot to the tree,
1687 * check if it was actually removed. For example
1688 * when snapshot mount point is busy, we will
1689 * have an error here, but there will be no need
1690 * to reinsert snapshot.
1692 if (avl_find(&sdp->sd_snaps, sep, &where) == NULL)
1693 avl_insert(&sdp->sd_snaps, sep, where);
1700 mutex_exit(&sdp->sd_lock);