diff --git a/sbin/mount_nullfs/mount_nullfs.8 b/sbin/mount_nullfs/mount_nullfs.8
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--- a/sbin/mount_nullfs/mount_nullfs.8
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@@ -1,275 +1,275 @@
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 .\" This code is derived from software donated to Berkeley by
 .\" John Heidemann of the UCLA Ficus project.
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 .\"     @(#)mount_null.8	8.6 (Berkeley) 5/1/95
 .\"
 .Dd March 24, 2024
 .Dt MOUNT_NULLFS 8
 .Os
 .Sh NAME
 .Nm mount_nullfs
 .Nd "mount a loopback file system sub-tree; demonstrate the use of a null file system layer"
 .Sh SYNOPSIS
 .Nm
 .Op Fl o Ar options
 .Ar target
 .Ar mount-point
 .Sh DESCRIPTION
 The
 .Nm
 utility creates a
 .Xr nullfs 5
 layer, duplicating a sub-tree of the file system
 name space under another part of the global file system namespace.
 This allows existing files and directories to be accessed
 using a different pathname.
 .Pp
 The primary differences between a virtual copy of the file system
 and a symbolic link are that the
 .Xr getcwd 3
 functions work correctly in the virtual copy, and that other file systems
 may be mounted on the virtual copy without affecting the original.
 A different device number for the virtual copy is returned by
 .Xr stat 2 ,
 but in other respects it is indistinguishable from the original.
 .Pp
 The
 .Nm
 utility supports mounting both directories and single files.
 Both
 .Ar target
 and
 .Ar mount_point
 must be the same type.
 Mounting directories to files or files to
 directories is not supported.
 .Pp
 The
 .Nm
 file system differs from a traditional
 loopback file system in two respects: it is implemented using
 a stackable layers techniques, and its
 .Do null-node Dc Ns s
 stack above
 all lower-layer vnodes, not just over directory vnodes.
 .Pp
 The options are as follows:
 .Bl -tag -width indent
 .It Fl o
 Options are specified with a
 .Fl o
 flag followed by a comma separated string of options.
 See the
 .Xr mount 8
 man page for possible options and their meanings.
 Additionally the following option is supported:
 .Bl -tag -width nocache
 .It Cm nocache
 Disable metadata caching in the null layer.
 Some lower-layer file systems may force this option.
 Depending on the access pattern,
 this may result in increased lock contention.
 .It Cm cache
-Force enable metadate caching.
+Force enable metadata caching.
 .El
 .El
 .Pp
 The
 .Dv vfs.nullfs.cache_vnodes
 sysctl specifies global default for mount-specific cache/nocache option.
 .Pp
 The null layer has two purposes.
 First, it serves as a demonstration of layering by providing a layer
 which does nothing.
 (It actually does everything the loopback file system does,
 which is slightly more than nothing.)
 Second, the null layer can serve as a prototype layer.
 Since it provides all necessary layer framework,
 new file system layers can be created very easily by starting
 with a null layer.
 .Pp
 The remainder of this man page examines the null layer as a basis
 for constructing new layers.
 .\"
 .\"
 .Sh INSTANTIATING NEW NULL LAYERS
 New null layers are created with
 .Nm .
 The
 .Nm
 utility takes two arguments, the pathname
 of the lower vfs (target-pn) and the pathname where the null
 layer will appear in the namespace (mount-point-pn).
 After
 the null layer is put into place, the contents
 of target-pn subtree will be aliased under mount-point-pn.
 .\"
 .\"
 .Sh OPERATION OF A NULL LAYER
 The null layer is the minimum file system layer,
 simply bypassing all possible operations to the lower layer
 for processing there.
 The majority of its activity centers
 on the bypass routine, through which nearly all vnode operations
 pass.
 .Pp
 The bypass routine accepts arbitrary vnode operations for
 handling by the lower layer.
 It begins by examining vnode
 operation arguments and replacing any null-nodes by their
 lower-layer equivalents.
 It then invokes the operation
 on the lower layer.
 Finally, it replaces the null-nodes
 in the arguments and, if a vnode is returned by the operation,
 stacks a null-node on top of the returned vnode.
 .Pp
 Although bypass handles most operations,
 .Em vop_getattr ,
 .Em vop_inactive ,
 .Em vop_reclaim ,
 and
 .Em vop_print
 are not bypassed.
 .Em Vop_getattr
 must change the fsid being returned.
 .Em Vop_inactive
 and
 .Em vop_reclaim
 are not bypassed so that
 they can handle freeing null-layer specific data.
 .Em Vop_print
 is not bypassed to avoid excessive debugging
 information.
 .\"
 .\"
 .Sh INSTANTIATING VNODE STACKS
 Mounting associates the null layer with a lower layer,
 in effect stacking two VFSes.
 Vnode stacks are instead
 created on demand as files are accessed.
 .Pp
 The initial mount creates a single vnode stack for the
 root of the new null layer.
 All other vnode stacks
 are created as a result of vnode operations on
 this or other null vnode stacks.
 .Pp
 New vnode stacks come into existence as a result of
 an operation which returns a vnode.
 The bypass routine stacks a null-node above the new
 vnode before returning it to the caller.
 .Pp
 For example, imagine mounting a null layer with
 .Bd -literal -offset indent
 mount_nullfs /usr/include /dev/layer/null
 .Ed
 .Pp
 Changing directory to
 .Pa /dev/layer/null
 will assign
 the root null-node (which was created when the null layer was mounted).
 Now consider opening
 .Pa sys .
 A vop_lookup would be
 done on the root null-node.
 This operation would bypass through
 to the lower layer which would return a vnode representing
 the UFS
 .Pa sys .
 Null_bypass then builds a null-node
 aliasing the UFS
 .Pa sys
 and returns this to the caller.
 Later operations on the null-node
 .Pa sys
 will repeat this
 process when constructing other vnode stacks.
 .\"
 .\"
 .Sh CREATING OTHER FILE SYSTEM LAYERS
 One of the easiest ways to construct new file system layers is to make
 a copy of the null layer, rename all files and variables, and
 then begin modifying the copy.
 The
 .Xr sed 1
 utility can be used to easily rename
 all variables.
 .Pp
 The umap layer is an example of a layer descended from the
 null layer.
 .\"
 .\"
 .Sh INVOKING OPERATIONS ON LOWER LAYERS
 There are two techniques to invoke operations on a lower layer
 when the operation cannot be completely bypassed.
 Each method
 is appropriate in different situations.
 In both cases,
 it is the responsibility of the aliasing layer to make
 the operation arguments "correct" for the lower layer
 by mapping a vnode argument to the lower layer.
 .Pp
 The first approach is to call the aliasing layer's bypass routine.
 This method is most suitable when you wish to invoke the operation
 currently being handled on the lower layer.
 It has the advantage that
 the bypass routine already must do argument mapping.
 An example of this is
 .Em null_getattrs
 in the null layer.
 .Pp
 A second approach is to directly invoke vnode operations on
 the lower layer with the
 .Em VOP_OPERATIONNAME
 interface.
 The advantage of this method is that it is easy to invoke
 arbitrary operations on the lower layer.
 The disadvantage
 is that vnode arguments must be manually mapped.
 .\"
 .\"
 .Sh SEE ALSO
 .Xr nullfs 5 ,
 .Xr mount 8
 .Pp
 UCLA Technical Report CSD-910056,
 .Em "Stackable Layers: an Architecture for File System Development" .
 .Sh HISTORY
 The
 .Nm mount_null
 utility first appeared in
 .Bx 4.4 .
 It was renamed to
 .Nm
 in
 .Fx 5.0 .