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) 2012, 2015 by Delphix. All rights reserved.
24 * Copyright 2015, OmniTI Computer Consulting, Inc. All rights reserved.
28 * ZFS control directory (a.k.a. ".zfs")
30 * This directory provides a common location for all ZFS meta-objects.
31 * Currently, this is only the 'snapshot' directory, but this may expand in the
32 * future. The elements are built using the GFS primitives, as the hierarchy
33 * does not actually exist on disk.
35 * For 'snapshot', we don't want to have all snapshots always mounted, because
36 * this would take up a huge amount of space in /etc/mnttab. We have three
39 * ctldir ------> snapshotdir -------> snapshot
45 * The 'snapshot' node contains just enough information to lookup '..' and act
46 * as a mountpoint for the snapshot. Whenever we lookup a specific snapshot, we
47 * perform an automount of the underlying filesystem and return the
48 * corresponding vnode.
50 * All mounts are handled automatically by the kernel, but unmounts are
51 * (currently) handled from user land. The main reason is that there is no
52 * reliable way to auto-unmount the filesystem when it's "no longer in use".
53 * When the user unmounts a filesystem, we call zfsctl_unmount(), which
54 * unmounts any snapshots within the snapshot directory.
56 * The '.zfs', '.zfs/snapshot', and all directories created under
57 * '.zfs/snapshot' (ie: '.zfs/snapshot/<snapname>') are all GFS nodes and
58 * share the same vfs_t as the head filesystem (what '.zfs' lives under).
60 * File systems mounted ontop of the GFS nodes '.zfs/snapshot/<snapname>'
61 * (ie: snapshots) are ZFS nodes and have their own unique vfs_t.
62 * However, vnodes within these mounted on file systems have their v_vfsp
63 * fields set to the head filesystem to make NFS happy (see
64 * zfsctl_snapdir_lookup()). We VFS_HOLD the head filesystem's vfs_t
65 * so that it cannot be freed until all snapshots have been unmounted.
68 #include <sys/types.h>
69 #include <sys/param.h>
70 #include <sys/libkern.h>
71 #include <sys/dirent.h>
72 #include <sys/zfs_context.h>
73 #include <sys/zfs_ctldir.h>
74 #include <sys/zfs_ioctl.h>
75 #include <sys/zfs_vfsops.h>
76 #include <sys/namei.h>
79 #include <sys/dsl_dataset.h>
80 #include <sys/dsl_destroy.h>
81 #include <sys/dsl_deleg.h>
82 #include <sys/mount.h>
84 #include <sys/sysproto.h>
86 #include "zfs_namecheck.h"
88 #include <sys/kernel.h>
89 #include <sys/ccompat.h>
91 /* Common access mode for all virtual directories under the ctldir */
92 const uint16_t zfsctl_ctldir_mode = S_IRUSR | S_IXUSR | S_IRGRP | S_IXGRP |
96 * "Synthetic" filesystem implementation.
100 * Assert that A implies B.
102 #define KASSERT_IMPLY(A, B, msg) KASSERT(!(A) || (B), (msg));
104 static MALLOC_DEFINE(M_SFSNODES, "sfs_nodes", "synthetic-fs nodes");
106 typedef struct sfs_node {
107 char sn_name[ZFS_MAX_DATASET_NAME_LEN];
108 uint64_t sn_parent_id;
113 * Check the parent's ID as well as the node's to account for a chance
114 * that IDs originating from different domains (snapshot IDs, artificial
115 * IDs, znode IDs) may clash.
118 sfs_compare_ids(struct vnode *vp, void *arg)
120 sfs_node_t *n1 = vp->v_data;
121 sfs_node_t *n2 = arg;
124 equal = n1->sn_id == n2->sn_id &&
125 n1->sn_parent_id == n2->sn_parent_id;
127 /* Zero means equality. */
132 sfs_vnode_get(const struct mount *mp, int flags, uint64_t parent_id,
133 uint64_t id, struct vnode **vpp)
139 search.sn_parent_id = parent_id;
140 err = vfs_hash_get(mp, (uint32_t)id, flags, curthread, vpp,
141 sfs_compare_ids, &search);
146 sfs_vnode_insert(struct vnode *vp, int flags, uint64_t parent_id,
147 uint64_t id, struct vnode **vpp)
151 KASSERT(vp->v_data != NULL, ("sfs_vnode_insert with NULL v_data"));
152 err = vfs_hash_insert(vp, (uint32_t)id, flags, curthread, vpp,
153 sfs_compare_ids, vp->v_data);
158 sfs_vnode_remove(struct vnode *vp)
163 typedef void sfs_vnode_setup_fn(vnode_t *vp, void *arg);
166 sfs_vgetx(struct mount *mp, int flags, uint64_t parent_id, uint64_t id,
167 const char *tag, struct vop_vector *vops,
168 sfs_vnode_setup_fn setup, void *arg,
174 error = sfs_vnode_get(mp, flags, parent_id, id, vpp);
175 if (error != 0 || *vpp != NULL) {
176 KASSERT_IMPLY(error == 0, (*vpp)->v_data != NULL,
177 "sfs vnode with no data");
181 /* Allocate a new vnode/inode. */
182 error = getnewvnode(tag, mp, vops, &vp);
189 * Exclusively lock the vnode vnode while it's being constructed.
191 lockmgr(vp->v_vnlock, LK_EXCLUSIVE, NULL);
192 error = insmntque(vp, mp);
200 error = sfs_vnode_insert(vp, flags, parent_id, id, vpp);
201 if (error != 0 || *vpp != NULL) {
202 KASSERT_IMPLY(error == 0, (*vpp)->v_data != NULL,
203 "sfs vnode with no data");
212 sfs_print_node(sfs_node_t *node)
214 printf("\tname = %s\n", node->sn_name);
215 printf("\tparent_id = %ju\n", (uintmax_t)node->sn_parent_id);
216 printf("\tid = %ju\n", (uintmax_t)node->sn_id);
220 sfs_alloc_node(size_t size, const char *name, uint64_t parent_id, uint64_t id)
222 struct sfs_node *node;
224 KASSERT(strlen(name) < sizeof (node->sn_name),
225 ("sfs node name is too long"));
226 KASSERT(size >= sizeof (*node), ("sfs node size is too small"));
227 node = malloc(size, M_SFSNODES, M_WAITOK | M_ZERO);
228 strlcpy(node->sn_name, name, sizeof (node->sn_name));
229 node->sn_parent_id = parent_id;
236 sfs_destroy_node(sfs_node_t *node)
238 free(node, M_SFSNODES);
242 sfs_reclaim_vnode(vnode_t *vp)
246 sfs_vnode_remove(vp);
253 sfs_readdir_common(uint64_t parent_id, uint64_t id, struct vop_readdir_args *ap,
254 uio_t *uio, off_t *offp)
259 /* Reset ncookies for subsequent use of vfs_read_dirent. */
260 if (ap->a_ncookies != NULL)
263 if (uio->uio_resid < sizeof (entry))
264 return (SET_ERROR(EINVAL));
266 if (uio->uio_offset < 0)
267 return (SET_ERROR(EINVAL));
268 if (uio->uio_offset == 0) {
270 entry.d_type = DT_DIR;
271 entry.d_name[0] = '.';
272 entry.d_name[1] = '\0';
274 entry.d_reclen = sizeof (entry);
275 error = vfs_read_dirent(ap, &entry, uio->uio_offset);
277 return (SET_ERROR(error));
280 if (uio->uio_offset < sizeof (entry))
281 return (SET_ERROR(EINVAL));
282 if (uio->uio_offset == sizeof (entry)) {
283 entry.d_fileno = parent_id;
284 entry.d_type = DT_DIR;
285 entry.d_name[0] = '.';
286 entry.d_name[1] = '.';
287 entry.d_name[2] = '\0';
289 entry.d_reclen = sizeof (entry);
290 error = vfs_read_dirent(ap, &entry, uio->uio_offset);
292 return (SET_ERROR(error));
296 *offp = 2 * sizeof (entry);
302 * .zfs inode namespace
304 * We need to generate unique inode numbers for all files and directories
305 * within the .zfs pseudo-filesystem. We use the following scheme:
310 * .zfs/snapshot/<snap> objectid(snap)
312 #define ZFSCTL_INO_SNAP(id) (id)
314 static struct vop_vector zfsctl_ops_root;
315 static struct vop_vector zfsctl_ops_snapdir;
316 static struct vop_vector zfsctl_ops_snapshot;
329 zfsctl_is_node(vnode_t *vp)
331 return (vn_matchops(vp, zfsctl_ops_root) ||
332 vn_matchops(vp, zfsctl_ops_snapdir) ||
333 vn_matchops(vp, zfsctl_ops_snapshot));
337 typedef struct zfsctl_root {
345 * Create the '.zfs' directory.
348 zfsctl_create(zfsvfs_t *zfsvfs)
350 zfsctl_root_t *dot_zfs;
355 ASSERT(zfsvfs->z_ctldir == NULL);
357 snapdir = sfs_alloc_node(sizeof (*snapdir), "snapshot", ZFSCTL_INO_ROOT,
359 dot_zfs = (zfsctl_root_t *)sfs_alloc_node(sizeof (*dot_zfs), ".zfs", 0,
361 dot_zfs->snapdir = snapdir;
363 VERIFY(VFS_ROOT(zfsvfs->z_vfs, LK_EXCLUSIVE, &rvp) == 0);
364 VERIFY(0 == sa_lookup(VTOZ(rvp)->z_sa_hdl, SA_ZPL_CRTIME(zfsvfs),
365 &crtime, sizeof (crtime)));
366 ZFS_TIME_DECODE(&dot_zfs->cmtime, crtime);
369 zfsvfs->z_ctldir = dot_zfs;
373 * Destroy the '.zfs' directory. Only called when the filesystem is unmounted.
374 * The nodes must not have any associated vnodes by now as they should be
378 zfsctl_destroy(zfsvfs_t *zfsvfs)
380 sfs_destroy_node(zfsvfs->z_ctldir->snapdir);
381 sfs_destroy_node((sfs_node_t *)zfsvfs->z_ctldir);
382 zfsvfs->z_ctldir = NULL;
386 zfsctl_fs_root_vnode(struct mount *mp, void *arg __unused, int flags,
389 return (VFS_ROOT(mp, flags, vpp));
393 zfsctl_common_vnode_setup(vnode_t *vp, void *arg)
395 ASSERT_VOP_ELOCKED(vp, __func__);
397 /* We support shared locking. */
404 zfsctl_root_vnode(struct mount *mp, void *arg __unused, int flags,
410 node = ((zfsvfs_t *)mp->mnt_data)->z_ctldir;
411 err = sfs_vgetx(mp, flags, 0, ZFSCTL_INO_ROOT, "zfs", &zfsctl_ops_root,
412 zfsctl_common_vnode_setup, node, vpp);
417 zfsctl_snapdir_vnode(struct mount *mp, void *arg __unused, int flags,
423 node = ((zfsvfs_t *)mp->mnt_data)->z_ctldir->snapdir;
424 err = sfs_vgetx(mp, flags, ZFSCTL_INO_ROOT, ZFSCTL_INO_SNAPDIR, "zfs",
425 &zfsctl_ops_snapdir, zfsctl_common_vnode_setup, node, vpp);
430 * Given a root znode, retrieve the associated .zfs directory.
431 * Add a hold to the vnode and return it.
434 zfsctl_root(zfsvfs_t *zfsvfs, int flags, vnode_t **vpp)
438 error = zfsctl_root_vnode(zfsvfs->z_vfs, NULL, flags, vpp);
443 * Common open routine. Disallow any write access.
446 zfsctl_common_open(struct vop_open_args *ap)
448 int flags = ap->a_mode;
451 return (SET_ERROR(EACCES));
457 * Common close routine. Nothing to do here.
461 zfsctl_common_close(struct vop_close_args *ap)
467 * Common access routine. Disallow writes.
470 zfsctl_common_access(struct vop_access_args *ap)
472 accmode_t accmode = ap->a_accmode;
474 if (accmode & VWRITE)
475 return (SET_ERROR(EACCES));
480 * Common getattr function. Fill in basic information.
483 zfsctl_common_getattr(vnode_t *vp, vattr_t *vap)
494 * We are a purely virtual object, so we have no
495 * blocksize or allocated blocks.
501 vap->va_mode = zfsctl_ctldir_mode;
504 * We live in the now (for atime).
508 /* FreeBSD: Reset chflags(2) flags. */
511 vap->va_nodeid = node->sn_id;
513 /* At least '.' and '..'. */
517 #ifndef _OPENSOLARIS_SYS_VNODE_H_
518 struct vop_fid_args {
525 zfsctl_common_fid(struct vop_fid_args *ap)
527 vnode_t *vp = ap->a_vp;
528 fid_t *fidp = (void *)ap->a_fid;
529 sfs_node_t *node = vp->v_data;
530 uint64_t object = node->sn_id;
534 zfid = (zfid_short_t *)fidp;
535 zfid->zf_len = SHORT_FID_LEN;
537 for (i = 0; i < sizeof (zfid->zf_object); i++)
538 zfid->zf_object[i] = (uint8_t)(object >> (8 * i));
540 /* .zfs nodes always have a generation number of 0 */
541 for (i = 0; i < sizeof (zfid->zf_gen); i++)
547 #ifndef _SYS_SYSPROTO_H_
548 struct vop_reclaim_args {
555 zfsctl_common_reclaim(struct vop_reclaim_args *ap)
557 vnode_t *vp = ap->a_vp;
559 (void) sfs_reclaim_vnode(vp);
563 #ifndef _SYS_SYSPROTO_H_
564 struct vop_print_args {
570 zfsctl_common_print(struct vop_print_args *ap)
572 sfs_print_node(ap->a_vp->v_data);
576 #ifndef _SYS_SYSPROTO_H_
577 struct vop_getattr_args {
580 struct ucred *a_cred;
585 * Get root directory attributes.
588 zfsctl_root_getattr(struct vop_getattr_args *ap)
590 struct vnode *vp = ap->a_vp;
591 struct vattr *vap = ap->a_vap;
592 zfsctl_root_t *node = vp->v_data;
594 zfsctl_common_getattr(vp, vap);
595 vap->va_ctime = node->cmtime;
596 vap->va_mtime = vap->va_ctime;
597 vap->va_birthtime = vap->va_ctime;
598 vap->va_nlink += 1; /* snapdir */
599 vap->va_size = vap->va_nlink;
604 * When we lookup "." we still can be asked to lock it
605 * differently, can't we?
608 zfsctl_relock_dot(vnode_t *dvp, int ltype)
611 if (ltype != VOP_ISLOCKED(dvp)) {
612 if (ltype == LK_EXCLUSIVE)
613 vn_lock(dvp, LK_UPGRADE | LK_RETRY);
614 else /* if (ltype == LK_SHARED) */
615 vn_lock(dvp, LK_DOWNGRADE | LK_RETRY);
617 /* Relock for the "." case may left us with reclaimed vnode. */
618 if (VN_IS_DOOMED(dvp)) {
620 return (SET_ERROR(ENOENT));
627 * Special case the handling of "..".
630 zfsctl_root_lookup(struct vop_lookup_args *ap)
632 struct componentname *cnp = ap->a_cnp;
633 vnode_t *dvp = ap->a_dvp;
634 vnode_t **vpp = ap->a_vpp;
635 int flags = ap->a_cnp->cn_flags;
636 int lkflags = ap->a_cnp->cn_lkflags;
637 int nameiop = ap->a_cnp->cn_nameiop;
640 ASSERT(dvp->v_type == VDIR);
642 if ((flags & ISLASTCN) != 0 && nameiop != LOOKUP)
643 return (SET_ERROR(ENOTSUP));
645 if (cnp->cn_namelen == 1 && *cnp->cn_nameptr == '.') {
646 err = zfsctl_relock_dot(dvp, lkflags & LK_TYPE_MASK);
649 } else if ((flags & ISDOTDOT) != 0) {
650 err = vn_vget_ino_gen(dvp, zfsctl_fs_root_vnode, NULL,
652 } else if (strncmp(cnp->cn_nameptr, "snapshot", cnp->cn_namelen) == 0) {
653 err = zfsctl_snapdir_vnode(dvp->v_mount, NULL, lkflags, vpp);
655 err = SET_ERROR(ENOENT);
663 zfsctl_root_readdir(struct vop_readdir_args *ap)
666 vnode_t *vp = ap->a_vp;
667 zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
668 zfsctl_root_t *node = vp->v_data;
669 uio_t *uio = ap->a_uio;
670 int *eofp = ap->a_eofflag;
674 ASSERT(vp->v_type == VDIR);
676 error = sfs_readdir_common(zfsvfs->z_root, ZFSCTL_INO_ROOT, ap, uio,
679 if (error == ENAMETOOLONG) /* ran out of destination space */
683 if (uio->uio_offset != dots_offset)
684 return (SET_ERROR(EINVAL));
686 CTASSERT(sizeof (node->snapdir->sn_name) <= sizeof (entry.d_name));
687 entry.d_fileno = node->snapdir->sn_id;
688 entry.d_type = DT_DIR;
689 strcpy(entry.d_name, node->snapdir->sn_name);
690 entry.d_namlen = strlen(entry.d_name);
691 entry.d_reclen = sizeof (entry);
692 error = vfs_read_dirent(ap, &entry, uio->uio_offset);
694 if (error == ENAMETOOLONG)
696 return (SET_ERROR(error));
704 zfsctl_root_vptocnp(struct vop_vptocnp_args *ap)
706 static const char dotzfs_name[4] = ".zfs";
710 if (*ap->a_buflen < sizeof (dotzfs_name))
711 return (SET_ERROR(ENOMEM));
713 error = vn_vget_ino_gen(ap->a_vp, zfsctl_fs_root_vnode, NULL,
716 return (SET_ERROR(error));
720 *ap->a_buflen -= sizeof (dotzfs_name);
721 bcopy(dotzfs_name, ap->a_buf + *ap->a_buflen, sizeof (dotzfs_name));
726 zfsctl_common_pathconf(struct vop_pathconf_args *ap)
729 * We care about ACL variables so that user land utilities like ls
730 * can display them correctly. Since the ctldir's st_dev is set to be
731 * the same as the parent dataset, we must support all variables that
734 switch (ap->a_name) {
736 *ap->a_retval = MIN(LONG_MAX, ZFS_LINK_MAX);
739 case _PC_FILESIZEBITS:
743 case _PC_MIN_HOLE_SIZE:
744 *ap->a_retval = (int)SPA_MINBLOCKSIZE;
747 case _PC_ACL_EXTENDED:
755 case _PC_ACL_PATH_MAX:
756 *ap->a_retval = ACL_MAX_ENTRIES;
760 *ap->a_retval = NAME_MAX;
764 return (vop_stdpathconf(ap));
769 * Returns a trivial ACL
772 zfsctl_common_getacl(struct vop_getacl_args *ap)
776 if (ap->a_type != ACL_TYPE_NFS4)
779 acl_nfs4_sync_acl_from_mode(ap->a_aclp, zfsctl_ctldir_mode, 0);
781 * acl_nfs4_sync_acl_from_mode assumes that the owner can always modify
782 * attributes. That is not the case for the ctldir, so we must clear
783 * those bits. We also must clear ACL_READ_NAMED_ATTRS, because xattrs
784 * aren't supported by the ctldir.
786 for (i = 0; i < ap->a_aclp->acl_cnt; i++) {
787 struct acl_entry *entry;
788 entry = &(ap->a_aclp->acl_entry[i]);
789 entry->ae_perm &= ~(ACL_WRITE_ACL | ACL_WRITE_OWNER |
790 ACL_WRITE_ATTRIBUTES | ACL_WRITE_NAMED_ATTRS |
791 ACL_READ_NAMED_ATTRS);
797 static struct vop_vector zfsctl_ops_root = {
798 .vop_default = &default_vnodeops,
799 #if __FreeBSD_version >= 1300121
800 .vop_fplookup_vexec = VOP_EAGAIN,
802 .vop_open = zfsctl_common_open,
803 .vop_close = zfsctl_common_close,
804 .vop_ioctl = VOP_EINVAL,
805 .vop_getattr = zfsctl_root_getattr,
806 .vop_access = zfsctl_common_access,
807 .vop_readdir = zfsctl_root_readdir,
808 .vop_lookup = zfsctl_root_lookup,
809 .vop_inactive = VOP_NULL,
810 .vop_reclaim = zfsctl_common_reclaim,
811 .vop_fid = zfsctl_common_fid,
812 .vop_print = zfsctl_common_print,
813 .vop_vptocnp = zfsctl_root_vptocnp,
814 .vop_pathconf = zfsctl_common_pathconf,
815 .vop_getacl = zfsctl_common_getacl,
817 VFS_VOP_VECTOR_REGISTER(zfsctl_ops_root);
820 zfsctl_snapshot_zname(vnode_t *vp, const char *name, int len, char *zname)
822 objset_t *os = ((zfsvfs_t *)((vp)->v_vfsp->vfs_data))->z_os;
824 dmu_objset_name(os, zname);
825 if (strlen(zname) + 1 + strlen(name) >= len)
826 return (SET_ERROR(ENAMETOOLONG));
827 (void) strcat(zname, "@");
828 (void) strcat(zname, name);
833 zfsctl_snapshot_lookup(vnode_t *vp, const char *name, uint64_t *id)
835 objset_t *os = ((zfsvfs_t *)((vp)->v_vfsp->vfs_data))->z_os;
838 err = dsl_dataset_snap_lookup(dmu_objset_ds(os), name, id);
843 * Given a vnode get a root vnode of a filesystem mounted on top of
844 * the vnode, if any. The root vnode is referenced and locked.
845 * If no filesystem is mounted then the orinal vnode remains referenced
846 * and locked. If any error happens the orinal vnode is unlocked and
850 zfsctl_mounted_here(vnode_t **vpp, int flags)
855 ASSERT_VOP_LOCKED(*vpp, __func__);
856 ASSERT3S((*vpp)->v_type, ==, VDIR);
858 if ((mp = (*vpp)->v_mountedhere) != NULL) {
859 err = vfs_busy(mp, 0);
860 KASSERT(err == 0, ("vfs_busy(mp, 0) failed with %d", err));
861 KASSERT(vrefcnt(*vpp) > 1, ("unreferenced mountpoint"));
863 err = VFS_ROOT(mp, flags, vpp);
867 return (EJUSTRETURN);
871 const char *snap_name;
873 } snapshot_setup_arg_t;
876 zfsctl_snapshot_vnode_setup(vnode_t *vp, void *arg)
878 snapshot_setup_arg_t *ssa = arg;
881 ASSERT_VOP_ELOCKED(vp, __func__);
883 node = sfs_alloc_node(sizeof (sfs_node_t),
884 ssa->snap_name, ZFSCTL_INO_SNAPDIR, ssa->snap_id);
885 zfsctl_common_vnode_setup(vp, node);
887 /* We have to support recursive locking. */
892 * Lookup entry point for the 'snapshot' directory. Try to open the
893 * snapshot if it exist, creating the pseudo filesystem vnode as necessary.
894 * Perform a mount of the associated dataset on top of the vnode.
895 * There are four possibilities:
896 * - the snapshot node and vnode do not exist
897 * - the snapshot vnode is covered by the mounted snapshot
898 * - the snapshot vnode is not covered yet, the mount operation is in progress
899 * - the snapshot vnode is not covered, because the snapshot has been unmounted
900 * The last two states are transient and should be relatively short-lived.
903 zfsctl_snapdir_lookup(struct vop_lookup_args *ap)
905 vnode_t *dvp = ap->a_dvp;
906 vnode_t **vpp = ap->a_vpp;
907 struct componentname *cnp = ap->a_cnp;
908 char name[NAME_MAX + 1];
909 char fullname[ZFS_MAX_DATASET_NAME_LEN];
911 size_t mountpoint_len;
912 zfsvfs_t *zfsvfs = dvp->v_vfsp->vfs_data;
914 int nameiop = cnp->cn_nameiop;
915 int lkflags = cnp->cn_lkflags;
916 int flags = cnp->cn_flags;
919 ASSERT(dvp->v_type == VDIR);
921 if ((flags & ISLASTCN) != 0 && nameiop != LOOKUP)
922 return (SET_ERROR(ENOTSUP));
924 if (cnp->cn_namelen == 1 && *cnp->cn_nameptr == '.') {
925 err = zfsctl_relock_dot(dvp, lkflags & LK_TYPE_MASK);
930 if (flags & ISDOTDOT) {
931 err = vn_vget_ino_gen(dvp, zfsctl_root_vnode, NULL, lkflags,
936 if (cnp->cn_namelen >= sizeof (name))
937 return (SET_ERROR(ENAMETOOLONG));
939 strlcpy(name, ap->a_cnp->cn_nameptr, ap->a_cnp->cn_namelen + 1);
940 err = zfsctl_snapshot_lookup(dvp, name, &snap_id);
942 return (SET_ERROR(ENOENT));
945 snapshot_setup_arg_t ssa;
947 ssa.snap_name = name;
948 ssa.snap_id = snap_id;
949 err = sfs_vgetx(dvp->v_mount, LK_SHARED, ZFSCTL_INO_SNAPDIR,
950 snap_id, "zfs", &zfsctl_ops_snapshot,
951 zfsctl_snapshot_vnode_setup, &ssa, vpp);
955 /* Check if a new vnode has just been created. */
956 if (VOP_ISLOCKED(*vpp) == LK_EXCLUSIVE)
960 * Check if a snapshot is already mounted on top of the vnode.
962 err = zfsctl_mounted_here(vpp, lkflags);
963 if (err != EJUSTRETURN)
967 * If the vnode is not covered, then either the mount operation
968 * is in progress or the snapshot has already been unmounted
969 * but the vnode hasn't been inactivated and reclaimed yet.
970 * We can try to re-use the vnode in the latter case.
973 if (((*vpp)->v_iflag & VI_MOUNT) == 0) {
975 * Upgrade to exclusive lock in order to:
976 * - avoid race conditions
977 * - satisfy the contract of mount_snapshot()
979 err = VOP_LOCK(*vpp, LK_TRYUPGRADE | LK_INTERLOCK);
987 * In this state we can loop on uncontested locks and starve
988 * the thread doing the lengthy, non-trivial mount operation.
989 * So, yield to prevent that from happening.
992 kern_yield(PRI_USER);
995 VERIFY0(zfsctl_snapshot_zname(dvp, name, sizeof (fullname), fullname));
997 mountpoint_len = strlen(dvp->v_vfsp->mnt_stat.f_mntonname) +
998 strlen("/" ZFS_CTLDIR_NAME "/snapshot/") + strlen(name) + 1;
999 mountpoint = kmem_alloc(mountpoint_len, KM_SLEEP);
1000 (void) snprintf(mountpoint, mountpoint_len,
1001 "%s/" ZFS_CTLDIR_NAME "/snapshot/%s",
1002 dvp->v_vfsp->mnt_stat.f_mntonname, name);
1004 err = mount_snapshot(curthread, vpp, "zfs", mountpoint, fullname, 0);
1005 kmem_free(mountpoint, mountpoint_len);
1008 * Fix up the root vnode mounted on .zfs/snapshot/<snapname>.
1010 * This is where we lie about our v_vfsp in order to
1011 * make .zfs/snapshot/<snapname> accessible over NFS
1012 * without requiring manual mounts of <snapname>.
1014 ASSERT(VTOZ(*vpp)->z_zfsvfs != zfsvfs);
1015 VTOZ(*vpp)->z_zfsvfs->z_parent = zfsvfs;
1017 /* Clear the root flag (set via VFS_ROOT) as well. */
1018 (*vpp)->v_vflag &= ~VV_ROOT;
1027 zfsctl_snapdir_readdir(struct vop_readdir_args *ap)
1029 char snapname[ZFS_MAX_DATASET_NAME_LEN];
1030 struct dirent entry;
1031 vnode_t *vp = ap->a_vp;
1032 zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
1033 uio_t *uio = ap->a_uio;
1034 int *eofp = ap->a_eofflag;
1038 ASSERT(vp->v_type == VDIR);
1040 error = sfs_readdir_common(ZFSCTL_INO_ROOT, ZFSCTL_INO_SNAPDIR, ap, uio,
1043 if (error == ENAMETOOLONG) /* ran out of destination space */
1053 cookie = uio->uio_offset - dots_offset;
1055 dsl_pool_config_enter(dmu_objset_pool(zfsvfs->z_os), FTAG);
1056 error = dmu_snapshot_list_next(zfsvfs->z_os, sizeof (snapname),
1057 snapname, &id, &cookie, NULL);
1058 dsl_pool_config_exit(dmu_objset_pool(zfsvfs->z_os), FTAG);
1060 if (error == ENOENT) {
1069 entry.d_fileno = id;
1070 entry.d_type = DT_DIR;
1071 strcpy(entry.d_name, snapname);
1072 entry.d_namlen = strlen(entry.d_name);
1073 entry.d_reclen = sizeof (entry);
1074 error = vfs_read_dirent(ap, &entry, uio->uio_offset);
1076 if (error == ENAMETOOLONG)
1079 return (SET_ERROR(error));
1081 uio->uio_offset = cookie + dots_offset;
1087 zfsctl_snapdir_getattr(struct vop_getattr_args *ap)
1089 vnode_t *vp = ap->a_vp;
1090 vattr_t *vap = ap->a_vap;
1091 zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
1093 uint64_t snap_count;
1097 ds = dmu_objset_ds(zfsvfs->z_os);
1098 zfsctl_common_getattr(vp, vap);
1099 vap->va_ctime = dmu_objset_snap_cmtime(zfsvfs->z_os);
1100 vap->va_mtime = vap->va_ctime;
1101 vap->va_birthtime = vap->va_ctime;
1102 if (dsl_dataset_phys(ds)->ds_snapnames_zapobj != 0) {
1103 err = zap_count(dmu_objset_pool(ds->ds_objset)->dp_meta_objset,
1104 dsl_dataset_phys(ds)->ds_snapnames_zapobj, &snap_count);
1109 vap->va_nlink += snap_count;
1111 vap->va_size = vap->va_nlink;
1117 static struct vop_vector zfsctl_ops_snapdir = {
1118 .vop_default = &default_vnodeops,
1119 #if __FreeBSD_version >= 1300121
1120 .vop_fplookup_vexec = VOP_EAGAIN,
1122 .vop_open = zfsctl_common_open,
1123 .vop_close = zfsctl_common_close,
1124 .vop_getattr = zfsctl_snapdir_getattr,
1125 .vop_access = zfsctl_common_access,
1126 .vop_readdir = zfsctl_snapdir_readdir,
1127 .vop_lookup = zfsctl_snapdir_lookup,
1128 .vop_reclaim = zfsctl_common_reclaim,
1129 .vop_fid = zfsctl_common_fid,
1130 .vop_print = zfsctl_common_print,
1131 .vop_pathconf = zfsctl_common_pathconf,
1132 .vop_getacl = zfsctl_common_getacl,
1134 VFS_VOP_VECTOR_REGISTER(zfsctl_ops_snapdir);
1138 zfsctl_snapshot_inactive(struct vop_inactive_args *ap)
1140 vnode_t *vp = ap->a_vp;
1142 VERIFY(vrecycle(vp) == 1);
1147 zfsctl_snapshot_reclaim(struct vop_reclaim_args *ap)
1149 vnode_t *vp = ap->a_vp;
1150 void *data = vp->v_data;
1152 sfs_reclaim_vnode(vp);
1153 sfs_destroy_node(data);
1158 zfsctl_snapshot_vptocnp(struct vop_vptocnp_args *ap)
1170 len = strlen(node->sn_name);
1171 if (*ap->a_buflen < len)
1172 return (SET_ERROR(ENOMEM));
1175 * Prevent unmounting of the snapshot while the vnode lock
1176 * is not held. That is not strictly required, but allows
1177 * us to assert that an uncovered snapshot vnode is never
1180 mp = vp->v_mountedhere;
1182 return (SET_ERROR(ENOENT));
1183 error = vfs_busy(mp, 0);
1184 KASSERT(error == 0, ("vfs_busy(mp, 0) failed with %d", error));
1187 * We can vput the vnode as we can now depend on the reference owned
1188 * by the busied mp. But we also need to hold the vnode, because
1189 * the reference may go after vfs_unbusy() which has to be called
1190 * before we can lock the vnode again.
1192 locked = VOP_ISLOCKED(vp);
1193 #if __FreeBSD_version >= 1300045
1194 enum vgetstate vs = vget_prep(vp);
1200 /* Look up .zfs/snapshot, our parent. */
1201 error = zfsctl_snapdir_vnode(vp->v_mount, NULL, LK_SHARED, &dvp);
1205 *ap->a_buflen -= len;
1206 bcopy(node->sn_name, ap->a_buf + *ap->a_buflen, len);
1209 #if __FreeBSD_version >= 1300045
1210 vget_finish(vp, locked | LK_RETRY, vs);
1212 vget(vp, locked | LK_VNHELD | LK_RETRY, curthread);
1218 * These VP's should never see the light of day. They should always
1221 static struct vop_vector zfsctl_ops_snapshot = {
1222 .vop_default = NULL, /* ensure very restricted access */
1223 #if __FreeBSD_version >= 1300121
1224 .vop_fplookup_vexec = VOP_EAGAIN,
1226 .vop_inactive = zfsctl_snapshot_inactive,
1227 #if __FreeBSD_version >= 1300045
1228 .vop_need_inactive = vop_stdneed_inactive,
1230 .vop_reclaim = zfsctl_snapshot_reclaim,
1231 .vop_vptocnp = zfsctl_snapshot_vptocnp,
1232 .vop_lock1 = vop_stdlock,
1233 .vop_unlock = vop_stdunlock,
1234 .vop_islocked = vop_stdislocked,
1235 .vop_advlockpurge = vop_stdadvlockpurge, /* called by vgone */
1236 .vop_print = zfsctl_common_print,
1238 VFS_VOP_VECTOR_REGISTER(zfsctl_ops_snapshot);
1241 zfsctl_lookup_objset(vfs_t *vfsp, uint64_t objsetid, zfsvfs_t **zfsvfsp)
1243 zfsvfs_t *zfsvfs __unused = vfsp->vfs_data;
1247 ASSERT(zfsvfs->z_ctldir != NULL);
1249 error = sfs_vnode_get(vfsp, LK_EXCLUSIVE,
1250 ZFSCTL_INO_SNAPDIR, objsetid, &vp);
1251 if (error == 0 && vp != NULL) {
1253 * XXX Probably need to at least reference, if not busy, the mp.
1255 if (vp->v_mountedhere != NULL)
1256 *zfsvfsp = vp->v_mountedhere->mnt_data;
1259 if (*zfsvfsp == NULL)
1260 return (SET_ERROR(EINVAL));
1265 * Unmount any snapshots for the given filesystem. This is called from
1266 * zfs_umount() - if we have a ctldir, then go through and unmount all the
1270 zfsctl_umount_snapshots(vfs_t *vfsp, int fflags, cred_t *cr)
1272 char snapname[ZFS_MAX_DATASET_NAME_LEN];
1273 zfsvfs_t *zfsvfs = vfsp->vfs_data;
1279 ASSERT(zfsvfs->z_ctldir != NULL);
1285 dsl_pool_config_enter(dmu_objset_pool(zfsvfs->z_os), FTAG);
1286 error = dmu_snapshot_list_next(zfsvfs->z_os, sizeof (snapname),
1287 snapname, &id, &cookie, NULL);
1288 dsl_pool_config_exit(dmu_objset_pool(zfsvfs->z_os), FTAG);
1290 if (error == ENOENT)
1296 error = sfs_vnode_get(vfsp, LK_EXCLUSIVE,
1297 ZFSCTL_INO_SNAPDIR, id, &vp);
1298 if (error != 0 || vp == NULL)
1301 mp = vp->v_mountedhere;
1304 * v_mountedhere being NULL means that the
1305 * (uncovered) vnode is in a transient state
1306 * (mounting or unmounting), so loop until it
1316 continue; /* no mountpoint, nothing to do */
1319 * The mount-point vnode is kept locked to avoid spurious EBUSY
1320 * from a concurrent umount.
1321 * The vnode lock must have recursive locking enabled.
1324 error = dounmount(mp, fflags, curthread);
1325 KASSERT_IMPLY(error == 0, vrefcnt(vp) == 1,
1326 ("extra references after unmount"));
1331 KASSERT_IMPLY((fflags & MS_FORCE) != 0, error == 0,
1332 ("force unmounting failed"));
1337 zfsctl_snapshot_unmount(const char *snapname, int flags __unused)
1340 zfsvfs_t *zfsvfs = NULL;
1342 if (strchr(snapname, '@') == NULL)
1345 int err = getzfsvfs(snapname, &zfsvfs);
1347 ASSERT3P(zfsvfs, ==, NULL);
1350 vfsp = zfsvfs->z_vfs;
1352 ASSERT(!dsl_pool_config_held(dmu_objset_pool(zfsvfs->z_os)));
1356 return (dounmount(vfsp, MS_FORCE, curthread));