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.\" Copyright (c) 2008 Joe Marcus Clarke
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.\" $FreeBSD: head/share/man/man9/VOP_VPTOCNP.9 279776 2015-03-08 10:52:10Z dchagin $
.\"
.Dd March 8, 2015
.Dt VOP_VPTOCNP 9
.Os
.Sh NAME
.Nm VOP_VPTOCNP
.Nd translate a vnode to its component name
.Sh SYNOPSIS
.In sys/param.h
.In sys/ucred.h
.In sys/vnode.h
.Ft int
.Fn VOP_VPTOCNP "struct vnode *vp" "struct vnode **dvp" "struct ucred *cred" "char *buf" "int *buflen"
.Sh DESCRIPTION
This translates a vnode into its component name, and writes that name to
the head of the buffer specified by
.Fa buf .
.Bl -tag -width buflen
.It Fa vp
The vnode to translate.
.It Fa dvp
The vnode of the parent directory of
.Fa vp .
.It Fa cred
The caller credentials.
.It Fa buf
The buffer into which to prepend the component name.
.It Fa buflen
The remaining size of the buffer.
.El
.Pp
The default implementation of
.Nm
scans through
.Fa vp Ns 's
parent directory looking for a dirent with a matching file number.
If
.Fa vp
is not a directory, then
.Nm
returns ENOENT.
.Sh LOCKS
The vnode should be locked on entry and will still be locked on exit.
The parent directory vnode will be unlocked on a successful exit.
However, it will have its use count incremented.
.Sh RETURN VALUES
Zero is returned on success, otherwise an error code is returned.
.Sh ERRORS
.Bl -tag -width Er
.It Bq Er ENOMEM
The buffer was not large enough to hold the vnode's component name.
.It Bq Er ENOENT
The vnode was not found on the file system.
.El
.Sh SEE ALSO
.Xr vnode 9 ,
.Xr VOP_LOOKUP 9
.Sh NOTES
This interface is a work in progress.
.Sh HISTORY
The function
.Nm
appeared in
.Fx 8.0 .
.Sh AUTHORS
This manual page was written by
.An Joe Marcus Clarke .