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;
317 static struct vop_vector zfsctl_ops_shares_dir;
330 zfsctl_is_node(vnode_t *vp)
332 return (vn_matchops(vp, zfsctl_ops_root) ||
333 vn_matchops(vp, zfsctl_ops_snapdir) ||
334 vn_matchops(vp, zfsctl_ops_snapshot) ||
335 vn_matchops(vp, zfsctl_ops_shares_dir));
339 typedef struct zfsctl_root {
347 * Create the '.zfs' directory.
350 zfsctl_create(zfsvfs_t *zfsvfs)
352 zfsctl_root_t *dot_zfs;
357 ASSERT(zfsvfs->z_ctldir == NULL);
359 snapdir = sfs_alloc_node(sizeof (*snapdir), "snapshot", ZFSCTL_INO_ROOT,
361 dot_zfs = (zfsctl_root_t *)sfs_alloc_node(sizeof (*dot_zfs), ".zfs", 0,
363 dot_zfs->snapdir = snapdir;
365 VERIFY(VFS_ROOT(zfsvfs->z_vfs, LK_EXCLUSIVE, &rvp) == 0);
366 VERIFY(0 == sa_lookup(VTOZ(rvp)->z_sa_hdl, SA_ZPL_CRTIME(zfsvfs),
367 &crtime, sizeof (crtime)));
368 ZFS_TIME_DECODE(&dot_zfs->cmtime, crtime);
371 zfsvfs->z_ctldir = dot_zfs;
375 * Destroy the '.zfs' directory. Only called when the filesystem is unmounted.
376 * The nodes must not have any associated vnodes by now as they should be
380 zfsctl_destroy(zfsvfs_t *zfsvfs)
382 sfs_destroy_node(zfsvfs->z_ctldir->snapdir);
383 sfs_destroy_node((sfs_node_t *)zfsvfs->z_ctldir);
384 zfsvfs->z_ctldir = NULL;
388 zfsctl_fs_root_vnode(struct mount *mp, void *arg __unused, int flags,
391 return (VFS_ROOT(mp, flags, vpp));
395 zfsctl_common_vnode_setup(vnode_t *vp, void *arg)
397 ASSERT_VOP_ELOCKED(vp, __func__);
399 /* We support shared locking. */
406 zfsctl_root_vnode(struct mount *mp, void *arg __unused, int flags,
412 node = ((zfsvfs_t *)mp->mnt_data)->z_ctldir;
413 err = sfs_vgetx(mp, flags, 0, ZFSCTL_INO_ROOT, "zfs", &zfsctl_ops_root,
414 zfsctl_common_vnode_setup, node, vpp);
419 zfsctl_snapdir_vnode(struct mount *mp, void *arg __unused, int flags,
425 node = ((zfsvfs_t *)mp->mnt_data)->z_ctldir->snapdir;
426 err = sfs_vgetx(mp, flags, ZFSCTL_INO_ROOT, ZFSCTL_INO_SNAPDIR, "zfs",
427 &zfsctl_ops_snapdir, zfsctl_common_vnode_setup, node, vpp);
432 * Given a root znode, retrieve the associated .zfs directory.
433 * Add a hold to the vnode and return it.
436 zfsctl_root(zfsvfs_t *zfsvfs, int flags, vnode_t **vpp)
440 error = zfsctl_root_vnode(zfsvfs->z_vfs, NULL, flags, vpp);
445 * Common open routine. Disallow any write access.
448 zfsctl_common_open(struct vop_open_args *ap)
450 int flags = ap->a_mode;
453 return (SET_ERROR(EACCES));
459 * Common close routine. Nothing to do here.
463 zfsctl_common_close(struct vop_close_args *ap)
469 * Common access routine. Disallow writes.
472 zfsctl_common_access(struct vop_access_args *ap)
474 accmode_t accmode = ap->a_accmode;
476 if (accmode & VWRITE)
477 return (SET_ERROR(EACCES));
482 * Common getattr function. Fill in basic information.
485 zfsctl_common_getattr(vnode_t *vp, vattr_t *vap)
496 * We are a purely virtual object, so we have no
497 * blocksize or allocated blocks.
503 vap->va_mode = zfsctl_ctldir_mode;
506 * We live in the now (for atime).
510 /* FreeBSD: Reset chflags(2) flags. */
513 vap->va_nodeid = node->sn_id;
515 /* At least '.' and '..'. */
519 #ifndef _OPENSOLARIS_SYS_VNODE_H_
520 struct vop_fid_args {
527 zfsctl_common_fid(struct vop_fid_args *ap)
529 vnode_t *vp = ap->a_vp;
530 fid_t *fidp = (void *)ap->a_fid;
531 sfs_node_t *node = vp->v_data;
532 uint64_t object = node->sn_id;
536 zfid = (zfid_short_t *)fidp;
537 zfid->zf_len = SHORT_FID_LEN;
539 for (i = 0; i < sizeof (zfid->zf_object); i++)
540 zfid->zf_object[i] = (uint8_t)(object >> (8 * i));
542 /* .zfs nodes always have a generation number of 0 */
543 for (i = 0; i < sizeof (zfid->zf_gen); i++)
549 #ifndef _SYS_SYSPROTO_H_
550 struct vop_reclaim_args {
557 zfsctl_common_reclaim(struct vop_reclaim_args *ap)
559 vnode_t *vp = ap->a_vp;
561 (void) sfs_reclaim_vnode(vp);
565 #ifndef _SYS_SYSPROTO_H_
566 struct vop_print_args {
572 zfsctl_common_print(struct vop_print_args *ap)
574 sfs_print_node(ap->a_vp->v_data);
578 #ifndef _SYS_SYSPROTO_H_
579 struct vop_getattr_args {
582 struct ucred *a_cred;
587 * Get root directory attributes.
590 zfsctl_root_getattr(struct vop_getattr_args *ap)
592 struct vnode *vp = ap->a_vp;
593 struct vattr *vap = ap->a_vap;
594 zfsctl_root_t *node = vp->v_data;
596 zfsctl_common_getattr(vp, vap);
597 vap->va_ctime = node->cmtime;
598 vap->va_mtime = vap->va_ctime;
599 vap->va_birthtime = vap->va_ctime;
600 vap->va_nlink += 1; /* snapdir */
601 vap->va_size = vap->va_nlink;
606 * When we lookup "." we still can be asked to lock it
607 * differently, can't we?
610 zfsctl_relock_dot(vnode_t *dvp, int ltype)
613 if (ltype != VOP_ISLOCKED(dvp)) {
614 if (ltype == LK_EXCLUSIVE)
615 vn_lock(dvp, LK_UPGRADE | LK_RETRY);
616 else /* if (ltype == LK_SHARED) */
617 vn_lock(dvp, LK_DOWNGRADE | LK_RETRY);
619 /* Relock for the "." case may left us with reclaimed vnode. */
620 if (VN_IS_DOOMED(dvp)) {
622 return (SET_ERROR(ENOENT));
629 * Special case the handling of "..".
632 zfsctl_root_lookup(struct vop_lookup_args *ap)
634 struct componentname *cnp = ap->a_cnp;
635 vnode_t *dvp = ap->a_dvp;
636 vnode_t **vpp = ap->a_vpp;
637 int flags = ap->a_cnp->cn_flags;
638 int lkflags = ap->a_cnp->cn_lkflags;
639 int nameiop = ap->a_cnp->cn_nameiop;
642 ASSERT(dvp->v_type == VDIR);
644 if ((flags & ISLASTCN) != 0 && nameiop != LOOKUP)
645 return (SET_ERROR(ENOTSUP));
647 if (cnp->cn_namelen == 1 && *cnp->cn_nameptr == '.') {
648 err = zfsctl_relock_dot(dvp, lkflags & LK_TYPE_MASK);
651 } else if ((flags & ISDOTDOT) != 0) {
652 err = vn_vget_ino_gen(dvp, zfsctl_fs_root_vnode, NULL,
654 } else if (strncmp(cnp->cn_nameptr, "snapshot", cnp->cn_namelen) == 0) {
655 err = zfsctl_snapdir_vnode(dvp->v_mount, NULL, lkflags, vpp);
657 err = SET_ERROR(ENOENT);
665 zfsctl_root_readdir(struct vop_readdir_args *ap)
668 vnode_t *vp = ap->a_vp;
669 zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
670 zfsctl_root_t *node = vp->v_data;
671 uio_t *uio = ap->a_uio;
672 int *eofp = ap->a_eofflag;
676 ASSERT(vp->v_type == VDIR);
678 error = sfs_readdir_common(zfsvfs->z_root, ZFSCTL_INO_ROOT, ap, uio,
681 if (error == ENAMETOOLONG) /* ran out of destination space */
685 if (uio->uio_offset != dots_offset)
686 return (SET_ERROR(EINVAL));
688 CTASSERT(sizeof (node->snapdir->sn_name) <= sizeof (entry.d_name));
689 entry.d_fileno = node->snapdir->sn_id;
690 entry.d_type = DT_DIR;
691 strcpy(entry.d_name, node->snapdir->sn_name);
692 entry.d_namlen = strlen(entry.d_name);
693 entry.d_reclen = sizeof (entry);
694 error = vfs_read_dirent(ap, &entry, uio->uio_offset);
696 if (error == ENAMETOOLONG)
698 return (SET_ERROR(error));
706 zfsctl_root_vptocnp(struct vop_vptocnp_args *ap)
708 static const char dotzfs_name[4] = ".zfs";
712 if (*ap->a_buflen < sizeof (dotzfs_name))
713 return (SET_ERROR(ENOMEM));
715 error = vn_vget_ino_gen(ap->a_vp, zfsctl_fs_root_vnode, NULL,
718 return (SET_ERROR(error));
722 *ap->a_buflen -= sizeof (dotzfs_name);
723 bcopy(dotzfs_name, ap->a_buf + *ap->a_buflen, sizeof (dotzfs_name));
728 zfsctl_common_pathconf(struct vop_pathconf_args *ap)
731 * We care about ACL variables so that user land utilities like ls
732 * can display them correctly. Since the ctldir's st_dev is set to be
733 * the same as the parent dataset, we must support all variables that
736 switch (ap->a_name) {
738 *ap->a_retval = MIN(LONG_MAX, ZFS_LINK_MAX);
741 case _PC_FILESIZEBITS:
745 case _PC_MIN_HOLE_SIZE:
746 *ap->a_retval = (int)SPA_MINBLOCKSIZE;
749 case _PC_ACL_EXTENDED:
757 case _PC_ACL_PATH_MAX:
758 *ap->a_retval = ACL_MAX_ENTRIES;
762 *ap->a_retval = NAME_MAX;
766 return (vop_stdpathconf(ap));
771 * Returns a trivial ACL
774 zfsctl_common_getacl(struct vop_getacl_args *ap)
778 if (ap->a_type != ACL_TYPE_NFS4)
781 acl_nfs4_sync_acl_from_mode(ap->a_aclp, zfsctl_ctldir_mode, 0);
783 * acl_nfs4_sync_acl_from_mode assumes that the owner can always modify
784 * attributes. That is not the case for the ctldir, so we must clear
785 * those bits. We also must clear ACL_READ_NAMED_ATTRS, because xattrs
786 * aren't supported by the ctldir.
788 for (i = 0; i < ap->a_aclp->acl_cnt; i++) {
789 struct acl_entry *entry;
790 entry = &(ap->a_aclp->acl_entry[i]);
791 entry->ae_perm &= ~(ACL_WRITE_ACL | ACL_WRITE_OWNER |
792 ACL_WRITE_ATTRIBUTES | ACL_WRITE_NAMED_ATTRS |
793 ACL_READ_NAMED_ATTRS);
799 static struct vop_vector zfsctl_ops_root = {
800 .vop_default = &default_vnodeops,
801 .vop_open = zfsctl_common_open,
802 .vop_close = zfsctl_common_close,
803 .vop_ioctl = VOP_EINVAL,
804 .vop_getattr = zfsctl_root_getattr,
805 .vop_access = zfsctl_common_access,
806 .vop_readdir = zfsctl_root_readdir,
807 .vop_lookup = zfsctl_root_lookup,
808 .vop_inactive = VOP_NULL,
809 .vop_reclaim = zfsctl_common_reclaim,
810 .vop_fid = zfsctl_common_fid,
811 .vop_print = zfsctl_common_print,
812 .vop_vptocnp = zfsctl_root_vptocnp,
813 .vop_pathconf = zfsctl_common_pathconf,
814 .vop_getacl = zfsctl_common_getacl,
816 VFS_VOP_VECTOR_REGISTER(zfsctl_ops_root);
819 zfsctl_snapshot_zname(vnode_t *vp, const char *name, int len, char *zname)
821 objset_t *os = ((zfsvfs_t *)((vp)->v_vfsp->vfs_data))->z_os;
823 dmu_objset_name(os, zname);
824 if (strlen(zname) + 1 + strlen(name) >= len)
825 return (SET_ERROR(ENAMETOOLONG));
826 (void) strcat(zname, "@");
827 (void) strcat(zname, name);
832 zfsctl_snapshot_lookup(vnode_t *vp, const char *name, uint64_t *id)
834 objset_t *os = ((zfsvfs_t *)((vp)->v_vfsp->vfs_data))->z_os;
837 err = dsl_dataset_snap_lookup(dmu_objset_ds(os), name, id);
842 * Given a vnode get a root vnode of a filesystem mounted on top of
843 * the vnode, if any. The root vnode is referenced and locked.
844 * If no filesystem is mounted then the orinal vnode remains referenced
845 * and locked. If any error happens the orinal vnode is unlocked and
849 zfsctl_mounted_here(vnode_t **vpp, int flags)
854 ASSERT_VOP_LOCKED(*vpp, __func__);
855 ASSERT3S((*vpp)->v_type, ==, VDIR);
857 if ((mp = (*vpp)->v_mountedhere) != NULL) {
858 err = vfs_busy(mp, 0);
859 KASSERT(err == 0, ("vfs_busy(mp, 0) failed with %d", err));
860 KASSERT(vrefcnt(*vpp) > 1, ("unreferenced mountpoint"));
862 err = VFS_ROOT(mp, flags, vpp);
866 return (EJUSTRETURN);
870 const char *snap_name;
872 } snapshot_setup_arg_t;
875 zfsctl_snapshot_vnode_setup(vnode_t *vp, void *arg)
877 snapshot_setup_arg_t *ssa = arg;
880 ASSERT_VOP_ELOCKED(vp, __func__);
882 node = sfs_alloc_node(sizeof (sfs_node_t),
883 ssa->snap_name, ZFSCTL_INO_SNAPDIR, ssa->snap_id);
884 zfsctl_common_vnode_setup(vp, node);
886 /* We have to support recursive locking. */
891 * Lookup entry point for the 'snapshot' directory. Try to open the
892 * snapshot if it exist, creating the pseudo filesystem vnode as necessary.
893 * Perform a mount of the associated dataset on top of the vnode.
894 * There are four possibilities:
895 * - the snapshot node and vnode do not exist
896 * - the snapshot vnode is covered by the mounted snapshot
897 * - the snapshot vnode is not covered yet, the mount operation is in progress
898 * - the snapshot vnode is not covered, because the snapshot has been unmounted
899 * The last two states are transient and should be relatively short-lived.
902 zfsctl_snapdir_lookup(struct vop_lookup_args *ap)
904 vnode_t *dvp = ap->a_dvp;
905 vnode_t **vpp = ap->a_vpp;
906 struct componentname *cnp = ap->a_cnp;
907 char name[NAME_MAX + 1];
908 char fullname[ZFS_MAX_DATASET_NAME_LEN];
910 size_t mountpoint_len;
911 zfsvfs_t *zfsvfs = dvp->v_vfsp->vfs_data;
913 int nameiop = cnp->cn_nameiop;
914 int lkflags = cnp->cn_lkflags;
915 int flags = cnp->cn_flags;
918 ASSERT(dvp->v_type == VDIR);
920 if ((flags & ISLASTCN) != 0 && nameiop != LOOKUP)
921 return (SET_ERROR(ENOTSUP));
923 if (cnp->cn_namelen == 1 && *cnp->cn_nameptr == '.') {
924 err = zfsctl_relock_dot(dvp, lkflags & LK_TYPE_MASK);
929 if (flags & ISDOTDOT) {
930 err = vn_vget_ino_gen(dvp, zfsctl_root_vnode, NULL, lkflags,
935 if (cnp->cn_namelen >= sizeof (name))
936 return (SET_ERROR(ENAMETOOLONG));
938 strlcpy(name, ap->a_cnp->cn_nameptr, ap->a_cnp->cn_namelen + 1);
939 err = zfsctl_snapshot_lookup(dvp, name, &snap_id);
941 return (SET_ERROR(ENOENT));
944 snapshot_setup_arg_t ssa;
946 ssa.snap_name = name;
947 ssa.snap_id = snap_id;
948 err = sfs_vgetx(dvp->v_mount, LK_SHARED, ZFSCTL_INO_SNAPDIR,
949 snap_id, "zfs", &zfsctl_ops_snapshot,
950 zfsctl_snapshot_vnode_setup, &ssa, vpp);
954 /* Check if a new vnode has just been created. */
955 if (VOP_ISLOCKED(*vpp) == LK_EXCLUSIVE)
959 * Check if a snapshot is already mounted on top of the vnode.
961 err = zfsctl_mounted_here(vpp, lkflags);
962 if (err != EJUSTRETURN)
966 * If the vnode is not covered, then either the mount operation
967 * is in progress or the snapshot has already been unmounted
968 * but the vnode hasn't been inactivated and reclaimed yet.
969 * We can try to re-use the vnode in the latter case.
972 if (((*vpp)->v_iflag & VI_MOUNT) == 0) {
974 * Upgrade to exclusive lock in order to:
975 * - avoid race conditions
976 * - satisfy the contract of mount_snapshot()
978 err = VOP_LOCK(*vpp, LK_TRYUPGRADE | LK_INTERLOCK);
986 * In this state we can loop on uncontested locks and starve
987 * the thread doing the lengthy, non-trivial mount operation.
988 * So, yield to prevent that from happening.
991 kern_yield(PRI_USER);
994 VERIFY0(zfsctl_snapshot_zname(dvp, name, sizeof (fullname), fullname));
996 mountpoint_len = strlen(dvp->v_vfsp->mnt_stat.f_mntonname) +
997 strlen("/" ZFS_CTLDIR_NAME "/snapshot/") + strlen(name) + 1;
998 mountpoint = kmem_alloc(mountpoint_len, KM_SLEEP);
999 (void) snprintf(mountpoint, mountpoint_len,
1000 "%s/" ZFS_CTLDIR_NAME "/snapshot/%s",
1001 dvp->v_vfsp->mnt_stat.f_mntonname, name);
1003 err = mount_snapshot(curthread, vpp, "zfs", mountpoint, fullname, 0);
1004 kmem_free(mountpoint, mountpoint_len);
1007 * Fix up the root vnode mounted on .zfs/snapshot/<snapname>.
1009 * This is where we lie about our v_vfsp in order to
1010 * make .zfs/snapshot/<snapname> accessible over NFS
1011 * without requiring manual mounts of <snapname>.
1013 ASSERT(VTOZ(*vpp)->z_zfsvfs != zfsvfs);
1014 VTOZ(*vpp)->z_zfsvfs->z_parent = zfsvfs;
1016 /* Clear the root flag (set via VFS_ROOT) as well. */
1017 (*vpp)->v_vflag &= ~VV_ROOT;
1026 zfsctl_snapdir_readdir(struct vop_readdir_args *ap)
1028 char snapname[ZFS_MAX_DATASET_NAME_LEN];
1029 struct dirent entry;
1030 vnode_t *vp = ap->a_vp;
1031 zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
1032 uio_t *uio = ap->a_uio;
1033 int *eofp = ap->a_eofflag;
1037 ASSERT(vp->v_type == VDIR);
1039 error = sfs_readdir_common(ZFSCTL_INO_ROOT, ZFSCTL_INO_SNAPDIR, ap, uio,
1042 if (error == ENAMETOOLONG) /* ran out of destination space */
1052 cookie = uio->uio_offset - dots_offset;
1054 dsl_pool_config_enter(dmu_objset_pool(zfsvfs->z_os), FTAG);
1055 error = dmu_snapshot_list_next(zfsvfs->z_os, sizeof (snapname),
1056 snapname, &id, &cookie, NULL);
1057 dsl_pool_config_exit(dmu_objset_pool(zfsvfs->z_os), FTAG);
1059 if (error == ENOENT) {
1068 entry.d_fileno = id;
1069 entry.d_type = DT_DIR;
1070 strcpy(entry.d_name, snapname);
1071 entry.d_namlen = strlen(entry.d_name);
1072 entry.d_reclen = sizeof (entry);
1073 error = vfs_read_dirent(ap, &entry, uio->uio_offset);
1075 if (error == ENAMETOOLONG)
1078 return (SET_ERROR(error));
1080 uio->uio_offset = cookie + dots_offset;
1086 zfsctl_snapdir_getattr(struct vop_getattr_args *ap)
1088 vnode_t *vp = ap->a_vp;
1089 vattr_t *vap = ap->a_vap;
1090 zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
1092 uint64_t snap_count;
1096 ds = dmu_objset_ds(zfsvfs->z_os);
1097 zfsctl_common_getattr(vp, vap);
1098 vap->va_ctime = dmu_objset_snap_cmtime(zfsvfs->z_os);
1099 vap->va_mtime = vap->va_ctime;
1100 vap->va_birthtime = vap->va_ctime;
1101 if (dsl_dataset_phys(ds)->ds_snapnames_zapobj != 0) {
1102 err = zap_count(dmu_objset_pool(ds->ds_objset)->dp_meta_objset,
1103 dsl_dataset_phys(ds)->ds_snapnames_zapobj, &snap_count);
1108 vap->va_nlink += snap_count;
1110 vap->va_size = vap->va_nlink;
1116 static struct vop_vector zfsctl_ops_snapdir = {
1117 .vop_default = &default_vnodeops,
1118 .vop_open = zfsctl_common_open,
1119 .vop_close = zfsctl_common_close,
1120 .vop_getattr = zfsctl_snapdir_getattr,
1121 .vop_access = zfsctl_common_access,
1122 .vop_readdir = zfsctl_snapdir_readdir,
1123 .vop_lookup = zfsctl_snapdir_lookup,
1124 .vop_reclaim = zfsctl_common_reclaim,
1125 .vop_fid = zfsctl_common_fid,
1126 .vop_print = zfsctl_common_print,
1127 .vop_pathconf = zfsctl_common_pathconf,
1128 .vop_getacl = zfsctl_common_getacl,
1130 VFS_VOP_VECTOR_REGISTER(zfsctl_ops_snapdir);
1134 zfsctl_snapshot_inactive(struct vop_inactive_args *ap)
1136 vnode_t *vp = ap->a_vp;
1138 VERIFY(vrecycle(vp) == 1);
1143 zfsctl_snapshot_reclaim(struct vop_reclaim_args *ap)
1145 vnode_t *vp = ap->a_vp;
1146 void *data = vp->v_data;
1148 sfs_reclaim_vnode(vp);
1149 sfs_destroy_node(data);
1154 zfsctl_snapshot_vptocnp(struct vop_vptocnp_args *ap)
1166 len = strlen(node->sn_name);
1167 if (*ap->a_buflen < len)
1168 return (SET_ERROR(ENOMEM));
1171 * Prevent unmounting of the snapshot while the vnode lock
1172 * is not held. That is not strictly required, but allows
1173 * us to assert that an uncovered snapshot vnode is never
1176 mp = vp->v_mountedhere;
1178 return (SET_ERROR(ENOENT));
1179 error = vfs_busy(mp, 0);
1180 KASSERT(error == 0, ("vfs_busy(mp, 0) failed with %d", error));
1183 * We can vput the vnode as we can now depend on the reference owned
1184 * by the busied mp. But we also need to hold the vnode, because
1185 * the reference may go after vfs_unbusy() which has to be called
1186 * before we can lock the vnode again.
1188 locked = VOP_ISLOCKED(vp);
1189 #if __FreeBSD_version >= 1300045
1190 enum vgetstate vs = vget_prep(vp);
1196 /* Look up .zfs/snapshot, our parent. */
1197 error = zfsctl_snapdir_vnode(vp->v_mount, NULL, LK_SHARED, &dvp);
1201 *ap->a_buflen -= len;
1202 bcopy(node->sn_name, ap->a_buf + *ap->a_buflen, len);
1205 #if __FreeBSD_version >= 1300045
1206 vget_finish(vp, locked | LK_RETRY, vs);
1208 vget(vp, locked | LK_VNHELD | LK_RETRY, curthread);
1214 * These VP's should never see the light of day. They should always
1217 static struct vop_vector zfsctl_ops_snapshot = {
1218 .vop_default = NULL, /* ensure very restricted access */
1219 .vop_inactive = zfsctl_snapshot_inactive,
1220 #if __FreeBSD_version >= 1300045
1221 .vop_need_inactive = vop_stdneed_inactive,
1223 .vop_reclaim = zfsctl_snapshot_reclaim,
1224 .vop_vptocnp = zfsctl_snapshot_vptocnp,
1225 .vop_lock1 = vop_stdlock,
1226 .vop_unlock = vop_stdunlock,
1227 .vop_islocked = vop_stdislocked,
1228 .vop_advlockpurge = vop_stdadvlockpurge, /* called by vgone */
1229 .vop_print = zfsctl_common_print,
1231 VFS_VOP_VECTOR_REGISTER(zfsctl_ops_snapshot);
1234 zfsctl_lookup_objset(vfs_t *vfsp, uint64_t objsetid, zfsvfs_t **zfsvfsp)
1236 zfsvfs_t *zfsvfs __unused = vfsp->vfs_data;
1240 ASSERT(zfsvfs->z_ctldir != NULL);
1242 error = sfs_vnode_get(vfsp, LK_EXCLUSIVE,
1243 ZFSCTL_INO_SNAPDIR, objsetid, &vp);
1244 if (error == 0 && vp != NULL) {
1246 * XXX Probably need to at least reference, if not busy, the mp.
1248 if (vp->v_mountedhere != NULL)
1249 *zfsvfsp = vp->v_mountedhere->mnt_data;
1252 if (*zfsvfsp == NULL)
1253 return (SET_ERROR(EINVAL));
1258 * Unmount any snapshots for the given filesystem. This is called from
1259 * zfs_umount() - if we have a ctldir, then go through and unmount all the
1263 zfsctl_umount_snapshots(vfs_t *vfsp, int fflags, cred_t *cr)
1265 char snapname[ZFS_MAX_DATASET_NAME_LEN];
1266 zfsvfs_t *zfsvfs = vfsp->vfs_data;
1272 ASSERT(zfsvfs->z_ctldir != NULL);
1278 dsl_pool_config_enter(dmu_objset_pool(zfsvfs->z_os), FTAG);
1279 error = dmu_snapshot_list_next(zfsvfs->z_os, sizeof (snapname),
1280 snapname, &id, &cookie, NULL);
1281 dsl_pool_config_exit(dmu_objset_pool(zfsvfs->z_os), FTAG);
1283 if (error == ENOENT)
1289 error = sfs_vnode_get(vfsp, LK_EXCLUSIVE,
1290 ZFSCTL_INO_SNAPDIR, id, &vp);
1291 if (error != 0 || vp == NULL)
1294 mp = vp->v_mountedhere;
1297 * v_mountedhere being NULL means that the
1298 * (uncovered) vnode is in a transient state
1299 * (mounting or unmounting), so loop until it
1309 continue; /* no mountpoint, nothing to do */
1312 * The mount-point vnode is kept locked to avoid spurious EBUSY
1313 * from a concurrent umount.
1314 * The vnode lock must have recursive locking enabled.
1317 error = dounmount(mp, fflags, curthread);
1318 KASSERT_IMPLY(error == 0, vrefcnt(vp) == 1,
1319 ("extra references after unmount"));
1324 KASSERT_IMPLY((fflags & MS_FORCE) != 0, error == 0,
1325 ("force unmounting failed"));
1330 zfsctl_snapshot_unmount(char *snapname, int flags __unused)
1333 zfsvfs_t *zfsvfs = NULL;
1335 if (strchr(snapname, '@') == NULL)
1338 int err = getzfsvfs(snapname, &zfsvfs);
1340 ASSERT3P(zfsvfs, ==, NULL);
1343 vfsp = zfsvfs->z_vfs;
1345 ASSERT(!dsl_pool_config_held(dmu_objset_pool(zfsvfs->z_os)));
1349 return (dounmount(vfsp, MS_FORCE, curthread));