VFS_MOUNT.9

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.Dd May 23, 2009
.Dt VFS_MOUNT 9
.Os
.Sh NAME
.Nm VFS_MOUNT
.Nd mount a file system
.Sh SYNOPSIS
.In sys/param.h
.In sys/mount.h
.In sys/vnode.h
.Ft int
.Fn VFS_MOUNT "struct mount *mp"
.Sh DESCRIPTION
The
.Fn VFS_MOUNT
macro mounts a file system into the system's namespace or updates the
attributes of an already mounted file system.
.Pp
The arguments it expects are:
.Bl -tag -width data
.It Fa mp
Structure representing the file system.
.El
.Pp
The
.Fn VFS_MOUNT
macro is called both to mount new file systems and to change the
attributes of an existing file system.
If the
.Dv MNT_UPDATE
flag is set in
.Fa mp->mnt_flag
then the file system should update its internal state from the value of
.Fa mp->mnt_flag .
This can be used, for instance, to convert a read-only file system to
read-write.
It is also used by
.Xr mountd 8
to update the NFS export information for the file system.
.Pp
If the
.Dv MNT_UPDATE
flag is not specified, then this is a newly mounted file system.
The file system code should allocate and initialize
any private data needed to represent
the file system (it can use the
.Fa mp->mnt_data
field to store this information).
.Sh SEE ALSO
.Xr VFS 9 ,
.Xr vnode 9
.Sh AUTHORS
This manual page was written by
.An Doug Rabson .