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-rw-r--r--uts/common/fs/zfs/zfs_ctldir.c1349
1 files changed, 1349 insertions, 0 deletions
diff --git a/uts/common/fs/zfs/zfs_ctldir.c b/uts/common/fs/zfs/zfs_ctldir.c
new file mode 100644
index 000000000000..815f8895e702
--- /dev/null
+++ b/uts/common/fs/zfs/zfs_ctldir.c
@@ -0,0 +1,1349 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ */
+
+/*
+ * ZFS control directory (a.k.a. ".zfs")
+ *
+ * This directory provides a common location for all ZFS meta-objects.
+ * Currently, this is only the 'snapshot' directory, but this may expand in the
+ * future. The elements are built using the GFS primitives, as the hierarchy
+ * does not actually exist on disk.
+ *
+ * For 'snapshot', we don't want to have all snapshots always mounted, because
+ * this would take up a huge amount of space in /etc/mnttab. We have three
+ * types of objects:
+ *
+ * ctldir ------> snapshotdir -------> snapshot
+ * |
+ * |
+ * V
+ * mounted fs
+ *
+ * The 'snapshot' node contains just enough information to lookup '..' and act
+ * as a mountpoint for the snapshot. Whenever we lookup a specific snapshot, we
+ * perform an automount of the underlying filesystem and return the
+ * corresponding vnode.
+ *
+ * All mounts are handled automatically by the kernel, but unmounts are
+ * (currently) handled from user land. The main reason is that there is no
+ * reliable way to auto-unmount the filesystem when it's "no longer in use".
+ * When the user unmounts a filesystem, we call zfsctl_unmount(), which
+ * unmounts any snapshots within the snapshot directory.
+ *
+ * The '.zfs', '.zfs/snapshot', and all directories created under
+ * '.zfs/snapshot' (ie: '.zfs/snapshot/<snapname>') are all GFS nodes and
+ * share the same vfs_t as the head filesystem (what '.zfs' lives under).
+ *
+ * File systems mounted ontop of the GFS nodes '.zfs/snapshot/<snapname>'
+ * (ie: snapshots) are ZFS nodes and have their own unique vfs_t.
+ * However, vnodes within these mounted on file systems have their v_vfsp
+ * fields set to the head filesystem to make NFS happy (see
+ * zfsctl_snapdir_lookup()). We VFS_HOLD the head filesystem's vfs_t
+ * so that it cannot be freed until all snapshots have been unmounted.
+ */
+
+#include <fs/fs_subr.h>
+#include <sys/zfs_ctldir.h>
+#include <sys/zfs_ioctl.h>
+#include <sys/zfs_vfsops.h>
+#include <sys/vfs_opreg.h>
+#include <sys/gfs.h>
+#include <sys/stat.h>
+#include <sys/dmu.h>
+#include <sys/dsl_deleg.h>
+#include <sys/mount.h>
+#include <sys/sunddi.h>
+
+#include "zfs_namecheck.h"
+
+typedef struct zfsctl_node {
+ gfs_dir_t zc_gfs_private;
+ uint64_t zc_id;
+ timestruc_t zc_cmtime; /* ctime and mtime, always the same */
+} zfsctl_node_t;
+
+typedef struct zfsctl_snapdir {
+ zfsctl_node_t sd_node;
+ kmutex_t sd_lock;
+ avl_tree_t sd_snaps;
+} zfsctl_snapdir_t;
+
+typedef struct {
+ char *se_name;
+ vnode_t *se_root;
+ avl_node_t se_node;
+} zfs_snapentry_t;
+
+static int
+snapentry_compare(const void *a, const void *b)
+{
+ const zfs_snapentry_t *sa = a;
+ const zfs_snapentry_t *sb = b;
+ int ret = strcmp(sa->se_name, sb->se_name);
+
+ if (ret < 0)
+ return (-1);
+ else if (ret > 0)
+ return (1);
+ else
+ return (0);
+}
+
+vnodeops_t *zfsctl_ops_root;
+vnodeops_t *zfsctl_ops_snapdir;
+vnodeops_t *zfsctl_ops_snapshot;
+vnodeops_t *zfsctl_ops_shares;
+vnodeops_t *zfsctl_ops_shares_dir;
+
+static const fs_operation_def_t zfsctl_tops_root[];
+static const fs_operation_def_t zfsctl_tops_snapdir[];
+static const fs_operation_def_t zfsctl_tops_snapshot[];
+static const fs_operation_def_t zfsctl_tops_shares[];
+
+static vnode_t *zfsctl_mknode_snapdir(vnode_t *);
+static vnode_t *zfsctl_mknode_shares(vnode_t *);
+static vnode_t *zfsctl_snapshot_mknode(vnode_t *, uint64_t objset);
+static int zfsctl_unmount_snap(zfs_snapentry_t *, int, cred_t *);
+
+static gfs_opsvec_t zfsctl_opsvec[] = {
+ { ".zfs", zfsctl_tops_root, &zfsctl_ops_root },
+ { ".zfs/snapshot", zfsctl_tops_snapdir, &zfsctl_ops_snapdir },
+ { ".zfs/snapshot/vnode", zfsctl_tops_snapshot, &zfsctl_ops_snapshot },
+ { ".zfs/shares", zfsctl_tops_shares, &zfsctl_ops_shares_dir },
+ { ".zfs/shares/vnode", zfsctl_tops_shares, &zfsctl_ops_shares },
+ { NULL }
+};
+
+/*
+ * Root directory elements. We only have two entries
+ * snapshot and shares.
+ */
+static gfs_dirent_t zfsctl_root_entries[] = {
+ { "snapshot", zfsctl_mknode_snapdir, GFS_CACHE_VNODE },
+ { "shares", zfsctl_mknode_shares, GFS_CACHE_VNODE },
+ { NULL }
+};
+
+/* include . and .. in the calculation */
+#define NROOT_ENTRIES ((sizeof (zfsctl_root_entries) / \
+ sizeof (gfs_dirent_t)) + 1)
+
+
+/*
+ * Initialize the various GFS pieces we'll need to create and manipulate .zfs
+ * directories. This is called from the ZFS init routine, and initializes the
+ * vnode ops vectors that we'll be using.
+ */
+void
+zfsctl_init(void)
+{
+ VERIFY(gfs_make_opsvec(zfsctl_opsvec) == 0);
+}
+
+void
+zfsctl_fini(void)
+{
+ /*
+ * Remove vfsctl vnode ops
+ */
+ if (zfsctl_ops_root)
+ vn_freevnodeops(zfsctl_ops_root);
+ if (zfsctl_ops_snapdir)
+ vn_freevnodeops(zfsctl_ops_snapdir);
+ if (zfsctl_ops_snapshot)
+ vn_freevnodeops(zfsctl_ops_snapshot);
+ if (zfsctl_ops_shares)
+ vn_freevnodeops(zfsctl_ops_shares);
+ if (zfsctl_ops_shares_dir)
+ vn_freevnodeops(zfsctl_ops_shares_dir);
+
+ zfsctl_ops_root = NULL;
+ zfsctl_ops_snapdir = NULL;
+ zfsctl_ops_snapshot = NULL;
+ zfsctl_ops_shares = NULL;
+ zfsctl_ops_shares_dir = NULL;
+}
+
+boolean_t
+zfsctl_is_node(vnode_t *vp)
+{
+ return (vn_matchops(vp, zfsctl_ops_root) ||
+ vn_matchops(vp, zfsctl_ops_snapdir) ||
+ vn_matchops(vp, zfsctl_ops_snapshot) ||
+ vn_matchops(vp, zfsctl_ops_shares) ||
+ vn_matchops(vp, zfsctl_ops_shares_dir));
+
+}
+
+/*
+ * Return the inode number associated with the 'snapshot' or
+ * 'shares' directory.
+ */
+/* ARGSUSED */
+static ino64_t
+zfsctl_root_inode_cb(vnode_t *vp, int index)
+{
+ zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
+
+ ASSERT(index <= 2);
+
+ if (index == 0)
+ return (ZFSCTL_INO_SNAPDIR);
+
+ return (zfsvfs->z_shares_dir);
+}
+
+/*
+ * Create the '.zfs' directory. This directory is cached as part of the VFS
+ * structure. This results in a hold on the vfs_t. The code in zfs_umount()
+ * therefore checks against a vfs_count of 2 instead of 1. This reference
+ * is removed when the ctldir is destroyed in the unmount.
+ */
+void
+zfsctl_create(zfsvfs_t *zfsvfs)
+{
+ vnode_t *vp, *rvp;
+ zfsctl_node_t *zcp;
+ uint64_t crtime[2];
+
+ ASSERT(zfsvfs->z_ctldir == NULL);
+
+ vp = gfs_root_create(sizeof (zfsctl_node_t), zfsvfs->z_vfs,
+ zfsctl_ops_root, ZFSCTL_INO_ROOT, zfsctl_root_entries,
+ zfsctl_root_inode_cb, MAXNAMELEN, NULL, NULL);
+ zcp = vp->v_data;
+ zcp->zc_id = ZFSCTL_INO_ROOT;
+
+ VERIFY(VFS_ROOT(zfsvfs->z_vfs, &rvp) == 0);
+ VERIFY(0 == sa_lookup(VTOZ(rvp)->z_sa_hdl, SA_ZPL_CRTIME(zfsvfs),
+ &crtime, sizeof (crtime)));
+ ZFS_TIME_DECODE(&zcp->zc_cmtime, crtime);
+ VN_RELE(rvp);
+
+ /*
+ * We're only faking the fact that we have a root of a filesystem for
+ * the sake of the GFS interfaces. Undo the flag manipulation it did
+ * for us.
+ */
+ vp->v_flag &= ~(VROOT | VNOCACHE | VNOMAP | VNOSWAP | VNOMOUNT);
+
+ zfsvfs->z_ctldir = vp;
+}
+
+/*
+ * Destroy the '.zfs' directory. Only called when the filesystem is unmounted.
+ * There might still be more references if we were force unmounted, but only
+ * new zfs_inactive() calls can occur and they don't reference .zfs
+ */
+void
+zfsctl_destroy(zfsvfs_t *zfsvfs)
+{
+ VN_RELE(zfsvfs->z_ctldir);
+ zfsvfs->z_ctldir = NULL;
+}
+
+/*
+ * Given a root znode, retrieve the associated .zfs directory.
+ * Add a hold to the vnode and return it.
+ */
+vnode_t *
+zfsctl_root(znode_t *zp)
+{
+ ASSERT(zfs_has_ctldir(zp));
+ VN_HOLD(zp->z_zfsvfs->z_ctldir);
+ return (zp->z_zfsvfs->z_ctldir);
+}
+
+/*
+ * Common open routine. Disallow any write access.
+ */
+/* ARGSUSED */
+static int
+zfsctl_common_open(vnode_t **vpp, int flags, cred_t *cr, caller_context_t *ct)
+{
+ if (flags & FWRITE)
+ return (EACCES);
+
+ return (0);
+}
+
+/*
+ * Common close routine. Nothing to do here.
+ */
+/* ARGSUSED */
+static int
+zfsctl_common_close(vnode_t *vpp, int flags, int count, offset_t off,
+ cred_t *cr, caller_context_t *ct)
+{
+ return (0);
+}
+
+/*
+ * Common access routine. Disallow writes.
+ */
+/* ARGSUSED */
+static int
+zfsctl_common_access(vnode_t *vp, int mode, int flags, cred_t *cr,
+ caller_context_t *ct)
+{
+ if (flags & V_ACE_MASK) {
+ if (mode & ACE_ALL_WRITE_PERMS)
+ return (EACCES);
+ } else {
+ if (mode & VWRITE)
+ return (EACCES);
+ }
+
+ return (0);
+}
+
+/*
+ * Common getattr function. Fill in basic information.
+ */
+static void
+zfsctl_common_getattr(vnode_t *vp, vattr_t *vap)
+{
+ timestruc_t now;
+
+ vap->va_uid = 0;
+ vap->va_gid = 0;
+ vap->va_rdev = 0;
+ /*
+ * We are a purely virtual object, so we have no
+ * blocksize or allocated blocks.
+ */
+ vap->va_blksize = 0;
+ vap->va_nblocks = 0;
+ vap->va_seq = 0;
+ vap->va_fsid = vp->v_vfsp->vfs_dev;
+ vap->va_mode = S_IRUSR | S_IXUSR | S_IRGRP | S_IXGRP |
+ S_IROTH | S_IXOTH;
+ vap->va_type = VDIR;
+ /*
+ * We live in the now (for atime).
+ */
+ gethrestime(&now);
+ vap->va_atime = now;
+}
+
+/*ARGSUSED*/
+static int
+zfsctl_common_fid(vnode_t *vp, fid_t *fidp, caller_context_t *ct)
+{
+ zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
+ zfsctl_node_t *zcp = vp->v_data;
+ uint64_t object = zcp->zc_id;
+ zfid_short_t *zfid;
+ int i;
+
+ ZFS_ENTER(zfsvfs);
+
+ if (fidp->fid_len < SHORT_FID_LEN) {
+ fidp->fid_len = SHORT_FID_LEN;
+ ZFS_EXIT(zfsvfs);
+ return (ENOSPC);
+ }
+
+ zfid = (zfid_short_t *)fidp;
+
+ zfid->zf_len = SHORT_FID_LEN;
+
+ for (i = 0; i < sizeof (zfid->zf_object); i++)
+ zfid->zf_object[i] = (uint8_t)(object >> (8 * i));
+
+ /* .zfs znodes always have a generation number of 0 */
+ for (i = 0; i < sizeof (zfid->zf_gen); i++)
+ zfid->zf_gen[i] = 0;
+
+ ZFS_EXIT(zfsvfs);
+ return (0);
+}
+
+
+/*ARGSUSED*/
+static int
+zfsctl_shares_fid(vnode_t *vp, fid_t *fidp, caller_context_t *ct)
+{
+ zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
+ znode_t *dzp;
+ int error;
+
+ ZFS_ENTER(zfsvfs);
+
+ if (zfsvfs->z_shares_dir == 0) {
+ ZFS_EXIT(zfsvfs);
+ return (ENOTSUP);
+ }
+
+ if ((error = zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp)) == 0) {
+ error = VOP_FID(ZTOV(dzp), fidp, ct);
+ VN_RELE(ZTOV(dzp));
+ }
+
+ ZFS_EXIT(zfsvfs);
+ return (error);
+}
+/*
+ * .zfs inode namespace
+ *
+ * We need to generate unique inode numbers for all files and directories
+ * within the .zfs pseudo-filesystem. We use the following scheme:
+ *
+ * ENTRY ZFSCTL_INODE
+ * .zfs 1
+ * .zfs/snapshot 2
+ * .zfs/snapshot/<snap> objectid(snap)
+ */
+
+#define ZFSCTL_INO_SNAP(id) (id)
+
+/*
+ * Get root directory attributes.
+ */
+/* ARGSUSED */
+static int
+zfsctl_root_getattr(vnode_t *vp, vattr_t *vap, int flags, cred_t *cr,
+ caller_context_t *ct)
+{
+ zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
+ zfsctl_node_t *zcp = vp->v_data;
+
+ ZFS_ENTER(zfsvfs);
+ vap->va_nodeid = ZFSCTL_INO_ROOT;
+ vap->va_nlink = vap->va_size = NROOT_ENTRIES;
+ vap->va_mtime = vap->va_ctime = zcp->zc_cmtime;
+
+ zfsctl_common_getattr(vp, vap);
+ ZFS_EXIT(zfsvfs);
+
+ return (0);
+}
+
+/*
+ * Special case the handling of "..".
+ */
+/* ARGSUSED */
+int
+zfsctl_root_lookup(vnode_t *dvp, char *nm, vnode_t **vpp, pathname_t *pnp,
+ int flags, vnode_t *rdir, cred_t *cr, caller_context_t *ct,
+ int *direntflags, pathname_t *realpnp)
+{
+ zfsvfs_t *zfsvfs = dvp->v_vfsp->vfs_data;
+ int err;
+
+ /*
+ * No extended attributes allowed under .zfs
+ */
+ if (flags & LOOKUP_XATTR)
+ return (EINVAL);
+
+ ZFS_ENTER(zfsvfs);
+
+ if (strcmp(nm, "..") == 0) {
+ err = VFS_ROOT(dvp->v_vfsp, vpp);
+ } else {
+ err = gfs_vop_lookup(dvp, nm, vpp, pnp, flags, rdir,
+ cr, ct, direntflags, realpnp);
+ }
+
+ ZFS_EXIT(zfsvfs);
+
+ return (err);
+}
+
+static int
+zfsctl_pathconf(vnode_t *vp, int cmd, ulong_t *valp, cred_t *cr,
+ caller_context_t *ct)
+{
+ /*
+ * We only care about ACL_ENABLED so that libsec can
+ * display ACL correctly and not default to POSIX draft.
+ */
+ if (cmd == _PC_ACL_ENABLED) {
+ *valp = _ACL_ACE_ENABLED;
+ return (0);
+ }
+
+ return (fs_pathconf(vp, cmd, valp, cr, ct));
+}
+
+static const fs_operation_def_t zfsctl_tops_root[] = {
+ { VOPNAME_OPEN, { .vop_open = zfsctl_common_open } },
+ { VOPNAME_CLOSE, { .vop_close = zfsctl_common_close } },
+ { VOPNAME_IOCTL, { .error = fs_inval } },
+ { VOPNAME_GETATTR, { .vop_getattr = zfsctl_root_getattr } },
+ { VOPNAME_ACCESS, { .vop_access = zfsctl_common_access } },
+ { VOPNAME_READDIR, { .vop_readdir = gfs_vop_readdir } },
+ { VOPNAME_LOOKUP, { .vop_lookup = zfsctl_root_lookup } },
+ { VOPNAME_SEEK, { .vop_seek = fs_seek } },
+ { VOPNAME_INACTIVE, { .vop_inactive = gfs_vop_inactive } },
+ { VOPNAME_PATHCONF, { .vop_pathconf = zfsctl_pathconf } },
+ { VOPNAME_FID, { .vop_fid = zfsctl_common_fid } },
+ { NULL }
+};
+
+static int
+zfsctl_snapshot_zname(vnode_t *vp, const char *name, int len, char *zname)
+{
+ objset_t *os = ((zfsvfs_t *)((vp)->v_vfsp->vfs_data))->z_os;
+
+ if (snapshot_namecheck(name, NULL, NULL) != 0)
+ return (EILSEQ);
+ dmu_objset_name(os, zname);
+ if (strlen(zname) + 1 + strlen(name) >= len)
+ return (ENAMETOOLONG);
+ (void) strcat(zname, "@");
+ (void) strcat(zname, name);
+ return (0);
+}
+
+static int
+zfsctl_unmount_snap(zfs_snapentry_t *sep, int fflags, cred_t *cr)
+{
+ vnode_t *svp = sep->se_root;
+ int error;
+
+ ASSERT(vn_ismntpt(svp));
+
+ /* this will be dropped by dounmount() */
+ if ((error = vn_vfswlock(svp)) != 0)
+ return (error);
+
+ VN_HOLD(svp);
+ error = dounmount(vn_mountedvfs(svp), fflags, cr);
+ if (error) {
+ VN_RELE(svp);
+ return (error);
+ }
+
+ /*
+ * We can't use VN_RELE(), as that will try to invoke
+ * zfsctl_snapdir_inactive(), which would cause us to destroy
+ * the sd_lock mutex held by our caller.
+ */
+ ASSERT(svp->v_count == 1);
+ gfs_vop_inactive(svp, cr, NULL);
+
+ kmem_free(sep->se_name, strlen(sep->se_name) + 1);
+ kmem_free(sep, sizeof (zfs_snapentry_t));
+
+ return (0);
+}
+
+static void
+zfsctl_rename_snap(zfsctl_snapdir_t *sdp, zfs_snapentry_t *sep, const char *nm)
+{
+ avl_index_t where;
+ vfs_t *vfsp;
+ refstr_t *pathref;
+ char newpath[MAXNAMELEN];
+ char *tail;
+
+ ASSERT(MUTEX_HELD(&sdp->sd_lock));
+ ASSERT(sep != NULL);
+
+ vfsp = vn_mountedvfs(sep->se_root);
+ ASSERT(vfsp != NULL);
+
+ vfs_lock_wait(vfsp);
+
+ /*
+ * Change the name in the AVL tree.
+ */
+ avl_remove(&sdp->sd_snaps, sep);
+ kmem_free(sep->se_name, strlen(sep->se_name) + 1);
+ sep->se_name = kmem_alloc(strlen(nm) + 1, KM_SLEEP);
+ (void) strcpy(sep->se_name, nm);
+ VERIFY(avl_find(&sdp->sd_snaps, sep, &where) == NULL);
+ avl_insert(&sdp->sd_snaps, sep, where);
+
+ /*
+ * Change the current mountpoint info:
+ * - update the tail of the mntpoint path
+ * - update the tail of the resource path
+ */
+ pathref = vfs_getmntpoint(vfsp);
+ (void) strncpy(newpath, refstr_value(pathref), sizeof (newpath));
+ VERIFY((tail = strrchr(newpath, '/')) != NULL);
+ *(tail+1) = '\0';
+ ASSERT3U(strlen(newpath) + strlen(nm), <, sizeof (newpath));
+ (void) strcat(newpath, nm);
+ refstr_rele(pathref);
+ vfs_setmntpoint(vfsp, newpath, 0);
+
+ pathref = vfs_getresource(vfsp);
+ (void) strncpy(newpath, refstr_value(pathref), sizeof (newpath));
+ VERIFY((tail = strrchr(newpath, '@')) != NULL);
+ *(tail+1) = '\0';
+ ASSERT3U(strlen(newpath) + strlen(nm), <, sizeof (newpath));
+ (void) strcat(newpath, nm);
+ refstr_rele(pathref);
+ vfs_setresource(vfsp, newpath, 0);
+
+ vfs_unlock(vfsp);
+}
+
+/*ARGSUSED*/
+static int
+zfsctl_snapdir_rename(vnode_t *sdvp, char *snm, vnode_t *tdvp, char *tnm,
+ cred_t *cr, caller_context_t *ct, int flags)
+{
+ zfsctl_snapdir_t *sdp = sdvp->v_data;
+ zfs_snapentry_t search, *sep;
+ zfsvfs_t *zfsvfs;
+ avl_index_t where;
+ char from[MAXNAMELEN], to[MAXNAMELEN];
+ char real[MAXNAMELEN];
+ int err;
+
+ zfsvfs = sdvp->v_vfsp->vfs_data;
+ ZFS_ENTER(zfsvfs);
+
+ if ((flags & FIGNORECASE) || zfsvfs->z_case == ZFS_CASE_INSENSITIVE) {
+ err = dmu_snapshot_realname(zfsvfs->z_os, snm, real,
+ MAXNAMELEN, NULL);
+ if (err == 0) {
+ snm = real;
+ } else if (err != ENOTSUP) {
+ ZFS_EXIT(zfsvfs);
+ return (err);
+ }
+ }
+
+ ZFS_EXIT(zfsvfs);
+
+ err = zfsctl_snapshot_zname(sdvp, snm, MAXNAMELEN, from);
+ if (!err)
+ err = zfsctl_snapshot_zname(tdvp, tnm, MAXNAMELEN, to);
+ if (!err)
+ err = zfs_secpolicy_rename_perms(from, to, cr);
+ if (err)
+ return (err);
+
+ /*
+ * Cannot move snapshots out of the snapdir.
+ */
+ if (sdvp != tdvp)
+ return (EINVAL);
+
+ if (strcmp(snm, tnm) == 0)
+ return (0);
+
+ mutex_enter(&sdp->sd_lock);
+
+ search.se_name = (char *)snm;
+ if ((sep = avl_find(&sdp->sd_snaps, &search, &where)) == NULL) {
+ mutex_exit(&sdp->sd_lock);
+ return (ENOENT);
+ }
+
+ err = dmu_objset_rename(from, to, B_FALSE);
+ if (err == 0)
+ zfsctl_rename_snap(sdp, sep, tnm);
+
+ mutex_exit(&sdp->sd_lock);
+
+ return (err);
+}
+
+/* ARGSUSED */
+static int
+zfsctl_snapdir_remove(vnode_t *dvp, char *name, vnode_t *cwd, cred_t *cr,
+ caller_context_t *ct, int flags)
+{
+ zfsctl_snapdir_t *sdp = dvp->v_data;
+ zfs_snapentry_t *sep;
+ zfs_snapentry_t search;
+ zfsvfs_t *zfsvfs;
+ char snapname[MAXNAMELEN];
+ char real[MAXNAMELEN];
+ int err;
+
+ zfsvfs = dvp->v_vfsp->vfs_data;
+ ZFS_ENTER(zfsvfs);
+
+ if ((flags & FIGNORECASE) || zfsvfs->z_case == ZFS_CASE_INSENSITIVE) {
+
+ err = dmu_snapshot_realname(zfsvfs->z_os, name, real,
+ MAXNAMELEN, NULL);
+ if (err == 0) {
+ name = real;
+ } else if (err != ENOTSUP) {
+ ZFS_EXIT(zfsvfs);
+ return (err);
+ }
+ }
+
+ ZFS_EXIT(zfsvfs);
+
+ err = zfsctl_snapshot_zname(dvp, name, MAXNAMELEN, snapname);
+ if (!err)
+ err = zfs_secpolicy_destroy_perms(snapname, cr);
+ if (err)
+ return (err);
+
+ mutex_enter(&sdp->sd_lock);
+
+ search.se_name = name;
+ sep = avl_find(&sdp->sd_snaps, &search, NULL);
+ if (sep) {
+ avl_remove(&sdp->sd_snaps, sep);
+ err = zfsctl_unmount_snap(sep, MS_FORCE, cr);
+ if (err)
+ avl_add(&sdp->sd_snaps, sep);
+ else
+ err = dmu_objset_destroy(snapname, B_FALSE);
+ } else {
+ err = ENOENT;
+ }
+
+ mutex_exit(&sdp->sd_lock);
+
+ return (err);
+}
+
+/*
+ * This creates a snapshot under '.zfs/snapshot'.
+ */
+/* ARGSUSED */
+static int
+zfsctl_snapdir_mkdir(vnode_t *dvp, char *dirname, vattr_t *vap, vnode_t **vpp,
+ cred_t *cr, caller_context_t *cc, int flags, vsecattr_t *vsecp)
+{
+ zfsvfs_t *zfsvfs = dvp->v_vfsp->vfs_data;
+ char name[MAXNAMELEN];
+ int err;
+ static enum symfollow follow = NO_FOLLOW;
+ static enum uio_seg seg = UIO_SYSSPACE;
+
+ if (snapshot_namecheck(dirname, NULL, NULL) != 0)
+ return (EILSEQ);
+
+ dmu_objset_name(zfsvfs->z_os, name);
+
+ *vpp = NULL;
+
+ err = zfs_secpolicy_snapshot_perms(name, cr);
+ if (err)
+ return (err);
+
+ if (err == 0) {
+ err = dmu_objset_snapshot(name, dirname, NULL, NULL,
+ B_FALSE, B_FALSE, -1);
+ if (err)
+ return (err);
+ err = lookupnameat(dirname, seg, follow, NULL, vpp, dvp);
+ }
+
+ return (err);
+}
+
+/*
+ * Lookup entry point for the 'snapshot' directory. Try to open the
+ * snapshot if it exist, creating the pseudo filesystem vnode as necessary.
+ * Perform a mount of the associated dataset on top of the vnode.
+ */
+/* ARGSUSED */
+static int
+zfsctl_snapdir_lookup(vnode_t *dvp, char *nm, vnode_t **vpp, pathname_t *pnp,
+ int flags, vnode_t *rdir, cred_t *cr, caller_context_t *ct,
+ int *direntflags, pathname_t *realpnp)
+{
+ zfsctl_snapdir_t *sdp = dvp->v_data;
+ objset_t *snap;
+ char snapname[MAXNAMELEN];
+ char real[MAXNAMELEN];
+ char *mountpoint;
+ zfs_snapentry_t *sep, search;
+ struct mounta margs;
+ vfs_t *vfsp;
+ size_t mountpoint_len;
+ avl_index_t where;
+ zfsvfs_t *zfsvfs = dvp->v_vfsp->vfs_data;
+ int err;
+
+ /*
+ * No extended attributes allowed under .zfs
+ */
+ if (flags & LOOKUP_XATTR)
+ return (EINVAL);
+
+ ASSERT(dvp->v_type == VDIR);
+
+ /*
+ * If we get a recursive call, that means we got called
+ * from the domount() code while it was trying to look up the
+ * spec (which looks like a local path for zfs). We need to
+ * add some flag to domount() to tell it not to do this lookup.
+ */
+ if (MUTEX_HELD(&sdp->sd_lock))
+ return (ENOENT);
+
+ ZFS_ENTER(zfsvfs);
+
+ if (gfs_lookup_dot(vpp, dvp, zfsvfs->z_ctldir, nm) == 0) {
+ ZFS_EXIT(zfsvfs);
+ return (0);
+ }
+
+ if (flags & FIGNORECASE) {
+ boolean_t conflict = B_FALSE;
+
+ err = dmu_snapshot_realname(zfsvfs->z_os, nm, real,
+ MAXNAMELEN, &conflict);
+ if (err == 0) {
+ nm = real;
+ } else if (err != ENOTSUP) {
+ ZFS_EXIT(zfsvfs);
+ return (err);
+ }
+ if (realpnp)
+ (void) strlcpy(realpnp->pn_buf, nm,
+ realpnp->pn_bufsize);
+ if (conflict && direntflags)
+ *direntflags = ED_CASE_CONFLICT;
+ }
+
+ mutex_enter(&sdp->sd_lock);
+ search.se_name = (char *)nm;
+ if ((sep = avl_find(&sdp->sd_snaps, &search, &where)) != NULL) {
+ *vpp = sep->se_root;
+ VN_HOLD(*vpp);
+ err = traverse(vpp);
+ if (err) {
+ VN_RELE(*vpp);
+ *vpp = NULL;
+ } else if (*vpp == sep->se_root) {
+ /*
+ * The snapshot was unmounted behind our backs,
+ * try to remount it.
+ */
+ goto domount;
+ } else {
+ /*
+ * VROOT was set during the traverse call. We need
+ * to clear it since we're pretending to be part
+ * of our parent's vfs.
+ */
+ (*vpp)->v_flag &= ~VROOT;
+ }
+ mutex_exit(&sdp->sd_lock);
+ ZFS_EXIT(zfsvfs);
+ return (err);
+ }
+
+ /*
+ * The requested snapshot is not currently mounted, look it up.
+ */
+ err = zfsctl_snapshot_zname(dvp, nm, MAXNAMELEN, snapname);
+ if (err) {
+ mutex_exit(&sdp->sd_lock);
+ ZFS_EXIT(zfsvfs);
+ /*
+ * handle "ls *" or "?" in a graceful manner,
+ * forcing EILSEQ to ENOENT.
+ * Since shell ultimately passes "*" or "?" as name to lookup
+ */
+ return (err == EILSEQ ? ENOENT : err);
+ }
+ if (dmu_objset_hold(snapname, FTAG, &snap) != 0) {
+ mutex_exit(&sdp->sd_lock);
+ ZFS_EXIT(zfsvfs);
+ return (ENOENT);
+ }
+
+ sep = kmem_alloc(sizeof (zfs_snapentry_t), KM_SLEEP);
+ sep->se_name = kmem_alloc(strlen(nm) + 1, KM_SLEEP);
+ (void) strcpy(sep->se_name, nm);
+ *vpp = sep->se_root = zfsctl_snapshot_mknode(dvp, dmu_objset_id(snap));
+ avl_insert(&sdp->sd_snaps, sep, where);
+
+ dmu_objset_rele(snap, FTAG);
+domount:
+ mountpoint_len = strlen(refstr_value(dvp->v_vfsp->vfs_mntpt)) +
+ strlen("/.zfs/snapshot/") + strlen(nm) + 1;
+ mountpoint = kmem_alloc(mountpoint_len, KM_SLEEP);
+ (void) snprintf(mountpoint, mountpoint_len, "%s/.zfs/snapshot/%s",
+ refstr_value(dvp->v_vfsp->vfs_mntpt), nm);
+
+ margs.spec = snapname;
+ margs.dir = mountpoint;
+ margs.flags = MS_SYSSPACE | MS_NOMNTTAB;
+ margs.fstype = "zfs";
+ margs.dataptr = NULL;
+ margs.datalen = 0;
+ margs.optptr = NULL;
+ margs.optlen = 0;
+
+ err = domount("zfs", &margs, *vpp, kcred, &vfsp);
+ kmem_free(mountpoint, mountpoint_len);
+
+ if (err == 0) {
+ /*
+ * Return the mounted root rather than the covered mount point.
+ * Takes the GFS vnode at .zfs/snapshot/<snapname> and returns
+ * the ZFS vnode mounted on top of the GFS node. This ZFS
+ * vnode is the root of the newly created vfsp.
+ */
+ VFS_RELE(vfsp);
+ err = traverse(vpp);
+ }
+
+ if (err == 0) {
+ /*
+ * Fix up the root vnode mounted on .zfs/snapshot/<snapname>.
+ *
+ * This is where we lie about our v_vfsp in order to
+ * make .zfs/snapshot/<snapname> accessible over NFS
+ * without requiring manual mounts of <snapname>.
+ */
+ ASSERT(VTOZ(*vpp)->z_zfsvfs != zfsvfs);
+ VTOZ(*vpp)->z_zfsvfs->z_parent = zfsvfs;
+ (*vpp)->v_vfsp = zfsvfs->z_vfs;
+ (*vpp)->v_flag &= ~VROOT;
+ }
+ mutex_exit(&sdp->sd_lock);
+ ZFS_EXIT(zfsvfs);
+
+ /*
+ * If we had an error, drop our hold on the vnode and
+ * zfsctl_snapshot_inactive() will clean up.
+ */
+ if (err) {
+ VN_RELE(*vpp);
+ *vpp = NULL;
+ }
+ return (err);
+}
+
+/* ARGSUSED */
+static int
+zfsctl_shares_lookup(vnode_t *dvp, char *nm, vnode_t **vpp, pathname_t *pnp,
+ int flags, vnode_t *rdir, cred_t *cr, caller_context_t *ct,
+ int *direntflags, pathname_t *realpnp)
+{
+ zfsvfs_t *zfsvfs = dvp->v_vfsp->vfs_data;
+ znode_t *dzp;
+ int error;
+
+ ZFS_ENTER(zfsvfs);
+
+ if (gfs_lookup_dot(vpp, dvp, zfsvfs->z_ctldir, nm) == 0) {
+ ZFS_EXIT(zfsvfs);
+ return (0);
+ }
+
+ if (zfsvfs->z_shares_dir == 0) {
+ ZFS_EXIT(zfsvfs);
+ return (ENOTSUP);
+ }
+ if ((error = zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp)) == 0)
+ error = VOP_LOOKUP(ZTOV(dzp), nm, vpp, pnp,
+ flags, rdir, cr, ct, direntflags, realpnp);
+
+ VN_RELE(ZTOV(dzp));
+ ZFS_EXIT(zfsvfs);
+
+ return (error);
+}
+
+/* ARGSUSED */
+static int
+zfsctl_snapdir_readdir_cb(vnode_t *vp, void *dp, int *eofp,
+ offset_t *offp, offset_t *nextp, void *data, int flags)
+{
+ zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
+ char snapname[MAXNAMELEN];
+ uint64_t id, cookie;
+ boolean_t case_conflict;
+ int error;
+
+ ZFS_ENTER(zfsvfs);
+
+ cookie = *offp;
+ error = dmu_snapshot_list_next(zfsvfs->z_os, MAXNAMELEN, snapname, &id,
+ &cookie, &case_conflict);
+ if (error) {
+ ZFS_EXIT(zfsvfs);
+ if (error == ENOENT) {
+ *eofp = 1;
+ return (0);
+ }
+ return (error);
+ }
+
+ if (flags & V_RDDIR_ENTFLAGS) {
+ edirent_t *eodp = dp;
+
+ (void) strcpy(eodp->ed_name, snapname);
+ eodp->ed_ino = ZFSCTL_INO_SNAP(id);
+ eodp->ed_eflags = case_conflict ? ED_CASE_CONFLICT : 0;
+ } else {
+ struct dirent64 *odp = dp;
+
+ (void) strcpy(odp->d_name, snapname);
+ odp->d_ino = ZFSCTL_INO_SNAP(id);
+ }
+ *nextp = cookie;
+
+ ZFS_EXIT(zfsvfs);
+
+ return (0);
+}
+
+/* ARGSUSED */
+static int
+zfsctl_shares_readdir(vnode_t *vp, uio_t *uiop, cred_t *cr, int *eofp,
+ caller_context_t *ct, int flags)
+{
+ zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
+ znode_t *dzp;
+ int error;
+
+ ZFS_ENTER(zfsvfs);
+
+ if (zfsvfs->z_shares_dir == 0) {
+ ZFS_EXIT(zfsvfs);
+ return (ENOTSUP);
+ }
+ if ((error = zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp)) == 0) {
+ error = VOP_READDIR(ZTOV(dzp), uiop, cr, eofp, ct, flags);
+ VN_RELE(ZTOV(dzp));
+ } else {
+ *eofp = 1;
+ error = ENOENT;
+ }
+
+ ZFS_EXIT(zfsvfs);
+ return (error);
+}
+
+/*
+ * pvp is the '.zfs' directory (zfsctl_node_t).
+ * Creates vp, which is '.zfs/snapshot' (zfsctl_snapdir_t).
+ *
+ * This function is the callback to create a GFS vnode for '.zfs/snapshot'
+ * when a lookup is performed on .zfs for "snapshot".
+ */
+vnode_t *
+zfsctl_mknode_snapdir(vnode_t *pvp)
+{
+ vnode_t *vp;
+ zfsctl_snapdir_t *sdp;
+
+ vp = gfs_dir_create(sizeof (zfsctl_snapdir_t), pvp,
+ zfsctl_ops_snapdir, NULL, NULL, MAXNAMELEN,
+ zfsctl_snapdir_readdir_cb, NULL);
+ sdp = vp->v_data;
+ sdp->sd_node.zc_id = ZFSCTL_INO_SNAPDIR;
+ sdp->sd_node.zc_cmtime = ((zfsctl_node_t *)pvp->v_data)->zc_cmtime;
+ mutex_init(&sdp->sd_lock, NULL, MUTEX_DEFAULT, NULL);
+ avl_create(&sdp->sd_snaps, snapentry_compare,
+ sizeof (zfs_snapentry_t), offsetof(zfs_snapentry_t, se_node));
+ return (vp);
+}
+
+vnode_t *
+zfsctl_mknode_shares(vnode_t *pvp)
+{
+ vnode_t *vp;
+ zfsctl_node_t *sdp;
+
+ vp = gfs_dir_create(sizeof (zfsctl_node_t), pvp,
+ zfsctl_ops_shares, NULL, NULL, MAXNAMELEN,
+ NULL, NULL);
+ sdp = vp->v_data;
+ sdp->zc_cmtime = ((zfsctl_node_t *)pvp->v_data)->zc_cmtime;
+ return (vp);
+
+}
+
+/* ARGSUSED */
+static int
+zfsctl_shares_getattr(vnode_t *vp, vattr_t *vap, int flags, cred_t *cr,
+ caller_context_t *ct)
+{
+ zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
+ znode_t *dzp;
+ int error;
+
+ ZFS_ENTER(zfsvfs);
+ if (zfsvfs->z_shares_dir == 0) {
+ ZFS_EXIT(zfsvfs);
+ return (ENOTSUP);
+ }
+ if ((error = zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp)) == 0) {
+ error = VOP_GETATTR(ZTOV(dzp), vap, flags, cr, ct);
+ VN_RELE(ZTOV(dzp));
+ }
+ ZFS_EXIT(zfsvfs);
+ return (error);
+
+
+}
+
+/* ARGSUSED */
+static int
+zfsctl_snapdir_getattr(vnode_t *vp, vattr_t *vap, int flags, cred_t *cr,
+ caller_context_t *ct)
+{
+ zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
+ zfsctl_snapdir_t *sdp = vp->v_data;
+
+ ZFS_ENTER(zfsvfs);
+ zfsctl_common_getattr(vp, vap);
+ vap->va_nodeid = gfs_file_inode(vp);
+ vap->va_nlink = vap->va_size = avl_numnodes(&sdp->sd_snaps) + 2;
+ vap->va_ctime = vap->va_mtime = dmu_objset_snap_cmtime(zfsvfs->z_os);
+ ZFS_EXIT(zfsvfs);
+
+ return (0);
+}
+
+/* ARGSUSED */
+static void
+zfsctl_snapdir_inactive(vnode_t *vp, cred_t *cr, caller_context_t *ct)
+{
+ zfsctl_snapdir_t *sdp = vp->v_data;
+ void *private;
+
+ private = gfs_dir_inactive(vp);
+ if (private != NULL) {
+ ASSERT(avl_numnodes(&sdp->sd_snaps) == 0);
+ mutex_destroy(&sdp->sd_lock);
+ avl_destroy(&sdp->sd_snaps);
+ kmem_free(private, sizeof (zfsctl_snapdir_t));
+ }
+}
+
+static const fs_operation_def_t zfsctl_tops_snapdir[] = {
+ { VOPNAME_OPEN, { .vop_open = zfsctl_common_open } },
+ { VOPNAME_CLOSE, { .vop_close = zfsctl_common_close } },
+ { VOPNAME_IOCTL, { .error = fs_inval } },
+ { VOPNAME_GETATTR, { .vop_getattr = zfsctl_snapdir_getattr } },
+ { VOPNAME_ACCESS, { .vop_access = zfsctl_common_access } },
+ { VOPNAME_RENAME, { .vop_rename = zfsctl_snapdir_rename } },
+ { VOPNAME_RMDIR, { .vop_rmdir = zfsctl_snapdir_remove } },
+ { VOPNAME_MKDIR, { .vop_mkdir = zfsctl_snapdir_mkdir } },
+ { VOPNAME_READDIR, { .vop_readdir = gfs_vop_readdir } },
+ { VOPNAME_LOOKUP, { .vop_lookup = zfsctl_snapdir_lookup } },
+ { VOPNAME_SEEK, { .vop_seek = fs_seek } },
+ { VOPNAME_INACTIVE, { .vop_inactive = zfsctl_snapdir_inactive } },
+ { VOPNAME_FID, { .vop_fid = zfsctl_common_fid } },
+ { NULL }
+};
+
+static const fs_operation_def_t zfsctl_tops_shares[] = {
+ { VOPNAME_OPEN, { .vop_open = zfsctl_common_open } },
+ { VOPNAME_CLOSE, { .vop_close = zfsctl_common_close } },
+ { VOPNAME_IOCTL, { .error = fs_inval } },
+ { VOPNAME_GETATTR, { .vop_getattr = zfsctl_shares_getattr } },
+ { VOPNAME_ACCESS, { .vop_access = zfsctl_common_access } },
+ { VOPNAME_READDIR, { .vop_readdir = zfsctl_shares_readdir } },
+ { VOPNAME_LOOKUP, { .vop_lookup = zfsctl_shares_lookup } },
+ { VOPNAME_SEEK, { .vop_seek = fs_seek } },
+ { VOPNAME_INACTIVE, { .vop_inactive = gfs_vop_inactive } },
+ { VOPNAME_FID, { .vop_fid = zfsctl_shares_fid } },
+ { NULL }
+};
+
+/*
+ * pvp is the GFS vnode '.zfs/snapshot'.
+ *
+ * This creates a GFS node under '.zfs/snapshot' representing each
+ * snapshot. This newly created GFS node is what we mount snapshot
+ * vfs_t's ontop of.
+ */
+static vnode_t *
+zfsctl_snapshot_mknode(vnode_t *pvp, uint64_t objset)
+{
+ vnode_t *vp;
+ zfsctl_node_t *zcp;
+
+ vp = gfs_dir_create(sizeof (zfsctl_node_t), pvp,
+ zfsctl_ops_snapshot, NULL, NULL, MAXNAMELEN, NULL, NULL);
+ zcp = vp->v_data;
+ zcp->zc_id = objset;
+
+ return (vp);
+}
+
+static void
+zfsctl_snapshot_inactive(vnode_t *vp, cred_t *cr, caller_context_t *ct)
+{
+ zfsctl_snapdir_t *sdp;
+ zfs_snapentry_t *sep, *next;
+ vnode_t *dvp;
+
+ VERIFY(gfs_dir_lookup(vp, "..", &dvp, cr, 0, NULL, NULL) == 0);
+ sdp = dvp->v_data;
+
+ mutex_enter(&sdp->sd_lock);
+
+ if (vp->v_count > 1) {
+ mutex_exit(&sdp->sd_lock);
+ return;
+ }
+ ASSERT(!vn_ismntpt(vp));
+
+ sep = avl_first(&sdp->sd_snaps);
+ while (sep != NULL) {
+ next = AVL_NEXT(&sdp->sd_snaps, sep);
+
+ if (sep->se_root == vp) {
+ avl_remove(&sdp->sd_snaps, sep);
+ kmem_free(sep->se_name, strlen(sep->se_name) + 1);
+ kmem_free(sep, sizeof (zfs_snapentry_t));
+ break;
+ }
+ sep = next;
+ }
+ ASSERT(sep != NULL);
+
+ mutex_exit(&sdp->sd_lock);
+ VN_RELE(dvp);
+
+ /*
+ * Dispose of the vnode for the snapshot mount point.
+ * This is safe to do because once this entry has been removed
+ * from the AVL tree, it can't be found again, so cannot become
+ * "active". If we lookup the same name again we will end up
+ * creating a new vnode.
+ */
+ gfs_vop_inactive(vp, cr, ct);
+}
+
+
+/*
+ * These VP's should never see the light of day. They should always
+ * be covered.
+ */
+static const fs_operation_def_t zfsctl_tops_snapshot[] = {
+ VOPNAME_INACTIVE, { .vop_inactive = zfsctl_snapshot_inactive },
+ NULL, NULL
+};
+
+int
+zfsctl_lookup_objset(vfs_t *vfsp, uint64_t objsetid, zfsvfs_t **zfsvfsp)
+{
+ zfsvfs_t *zfsvfs = vfsp->vfs_data;
+ vnode_t *dvp, *vp;
+ zfsctl_snapdir_t *sdp;
+ zfsctl_node_t *zcp;
+ zfs_snapentry_t *sep;
+ int error;
+
+ ASSERT(zfsvfs->z_ctldir != NULL);
+ error = zfsctl_root_lookup(zfsvfs->z_ctldir, "snapshot", &dvp,
+ NULL, 0, NULL, kcred, NULL, NULL, NULL);
+ if (error != 0)
+ return (error);
+ sdp = dvp->v_data;
+
+ mutex_enter(&sdp->sd_lock);
+ sep = avl_first(&sdp->sd_snaps);
+ while (sep != NULL) {
+ vp = sep->se_root;
+ zcp = vp->v_data;
+ if (zcp->zc_id == objsetid)
+ break;
+
+ sep = AVL_NEXT(&sdp->sd_snaps, sep);
+ }
+
+ if (sep != NULL) {
+ VN_HOLD(vp);
+ /*
+ * Return the mounted root rather than the covered mount point.
+ * Takes the GFS vnode at .zfs/snapshot/<snapshot objsetid>
+ * and returns the ZFS vnode mounted on top of the GFS node.
+ * This ZFS vnode is the root of the vfs for objset 'objsetid'.
+ */
+ error = traverse(&vp);
+ if (error == 0) {
+ if (vp == sep->se_root)
+ error = EINVAL;
+ else
+ *zfsvfsp = VTOZ(vp)->z_zfsvfs;
+ }
+ mutex_exit(&sdp->sd_lock);
+ VN_RELE(vp);
+ } else {
+ error = EINVAL;
+ mutex_exit(&sdp->sd_lock);
+ }
+
+ VN_RELE(dvp);
+
+ return (error);
+}
+
+/*
+ * Unmount any snapshots for the given filesystem. This is called from
+ * zfs_umount() - if we have a ctldir, then go through and unmount all the
+ * snapshots.
+ */
+int
+zfsctl_umount_snapshots(vfs_t *vfsp, int fflags, cred_t *cr)
+{
+ zfsvfs_t *zfsvfs = vfsp->vfs_data;
+ vnode_t *dvp;
+ zfsctl_snapdir_t *sdp;
+ zfs_snapentry_t *sep, *next;
+ int error;
+
+ ASSERT(zfsvfs->z_ctldir != NULL);
+ error = zfsctl_root_lookup(zfsvfs->z_ctldir, "snapshot", &dvp,
+ NULL, 0, NULL, cr, NULL, NULL, NULL);
+ if (error != 0)
+ return (error);
+ sdp = dvp->v_data;
+
+ mutex_enter(&sdp->sd_lock);
+
+ sep = avl_first(&sdp->sd_snaps);
+ while (sep != NULL) {
+ next = AVL_NEXT(&sdp->sd_snaps, sep);
+
+ /*
+ * If this snapshot is not mounted, then it must
+ * have just been unmounted by somebody else, and
+ * will be cleaned up by zfsctl_snapdir_inactive().
+ */
+ if (vn_ismntpt(sep->se_root)) {
+ avl_remove(&sdp->sd_snaps, sep);
+ error = zfsctl_unmount_snap(sep, fflags, cr);
+ if (error) {
+ avl_add(&sdp->sd_snaps, sep);
+ break;
+ }
+ }
+ sep = next;
+ }
+
+ mutex_exit(&sdp->sd_lock);
+ VN_RELE(dvp);
+
+ return (error);
+}