| mount_nullfs.8 (75670) | mount_nullfs.8 (77042) |
|---|---|
| 1.\" 2.\" Copyright (c) 1992, 1993, 1994 3.\" The Regents of the University of California. All rights reserved. 4.\" 5.\" This code is derived from software donated to Berkeley by 6.\" John Heidemann of the UCLA Ficus project. 7.\" 8.\" --- 21 unchanged lines hidden (view full) --- 30.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35.\" SUCH DAMAGE. 36.\" 37.\" @(#)mount_null.8 8.6 (Berkeley) 5/1/95 | 1.\" 2.\" Copyright (c) 1992, 1993, 1994 3.\" The Regents of the University of California. All rights reserved. 4.\" 5.\" This code is derived from software donated to Berkeley by 6.\" John Heidemann of the UCLA Ficus project. 7.\" 8.\" --- 21 unchanged lines hidden (view full) --- 30.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35.\" SUCH DAMAGE. 36.\" 37.\" @(#)mount_null.8 8.6 (Berkeley) 5/1/95 |
| 38.\" $FreeBSD: head/sbin/mount_nullfs/mount_nullfs.8 75670 2001-04-18 15:54:10Z ru $ | 38.\" $FreeBSD: head/sbin/mount_nullfs/mount_nullfs.8 77042 2001-05-23 14:58:19Z ru $ |
| 39.\" 40.Dd May 1, 1995 | 39.\" 40.Dd May 1, 1995 |
| 41.Dt MOUNT_NULL 8 42.Os BSD 4.4 | 41.Dt MOUNT_NULLFS 8 42.Os |
| 43.Sh NAME | 43.Sh NAME |
| 44.Nm mount_null | 44.Nm mount_nullfs |
| 45.Nd "mount a loopback filesystem sub-tree; demonstrate the use of a null file system layer" 46.Sh SYNOPSIS 47.Nm 48.Op Fl o Ar options 49.Ar target 50.Ar mount-point 51.Sh DESCRIPTION 52The --- 44 unchanged lines hidden (view full) --- 97with a null layer. 98.Pp 99The remainder of this man page examines the null layer as a basis 100for constructing new layers. 101.\" 102.\" 103.Sh INSTANTIATING NEW NULL LAYERS 104New null layers are created with | 45.Nd "mount a loopback filesystem sub-tree; demonstrate the use of a null file system layer" 46.Sh SYNOPSIS 47.Nm 48.Op Fl o Ar options 49.Ar target 50.Ar mount-point 51.Sh DESCRIPTION 52The --- 44 unchanged lines hidden (view full) --- 97with a null layer. 98.Pp 99The remainder of this man page examines the null layer as a basis 100for constructing new layers. 101.\" 102.\" 103.Sh INSTANTIATING NEW NULL LAYERS 104New null layers are created with |
| 105.Xr mount_null 8 . 106.Xr Mount_null 8 | 105.Nm . 106.Nm Mount_nullfs |
| 107takes two arguments, the pathname 108of the lower vfs (target-pn) and the pathname where the null 109layer will appear in the namespace (mount-point-pn). After 110the null layer is put into place, the contents 111of target-pn subtree will be aliased under mount-point-pn. 112.\" 113.\" 114.Sh OPERATION OF A NULL LAYER --- 42 unchanged lines hidden (view full) --- 157.Pp 158New vnode stacks come into existence as a result of 159an operation which returns a vnode. 160The bypass routine stacks a null-node above the new 161vnode before returning it to the caller. 162.Pp 163For example, imagine mounting a null layer with 164.Bd -literal -offset indent | 107takes two arguments, the pathname 108of the lower vfs (target-pn) and the pathname where the null 109layer will appear in the namespace (mount-point-pn). After 110the null layer is put into place, the contents 111of target-pn subtree will be aliased under mount-point-pn. 112.\" 113.\" 114.Sh OPERATION OF A NULL LAYER --- 42 unchanged lines hidden (view full) --- 157.Pp 158New vnode stacks come into existence as a result of 159an operation which returns a vnode. 160The bypass routine stacks a null-node above the new 161vnode before returning it to the caller. 162.Pp 163For example, imagine mounting a null layer with 164.Bd -literal -offset indent |
| 165mount_null /usr/include /dev/layer/null | 165mount_nullfs /usr/include /dev/layer/null |
| 166.Ed 167Changing directory to 168.Pa /dev/layer/null 169will assign 170the root null-node (which was created when the null layer was mounted). 171Now consider opening 172.Pa sys . 173A vop_lookup would be --- 70 unchanged lines hidden --- | 166.Ed 167Changing directory to 168.Pa /dev/layer/null 169will assign 170the root null-node (which was created when the null layer was mounted). 171Now consider opening 172.Pa sys . 173A vop_lookup would be --- 70 unchanged lines hidden --- |