VOP_LINK(9) BSD Kernel Developer's Manual VOP_LINK(9)NAMEVOP_LINK — create a new name for a file
SYNOPSIS
#include <sys/param.h>
#include <sys/vnode.h>
int
VOP_LINK(struct vnode *dvp, struct vnode *vp, struct componentname *cnp);
DESCRIPTION
This links a new name in the specified directory to an existing file.
Its arguments are:
dvp the vnode of the directory
vp the vnode of the file to be linked
cnp pathname information about the file
The pathname info must be released on exit. The directory and file
vnodes should NOT be released on exit.
LOCKS
The directory, dvp is locked on entry and should remain locked on return.
The file vp is not locked on entry and should remain that way on return.
If your VOP code locks vp, it must be sure to unlock prior to returning.
RETURN VALUES
Zero is returned if the file was linked successfully, otherwise an error
is returned.
PSEUDOCODE
int
vop_link(struct vnode *dvp, struct vnode *vp, struct componentname *cnp)
{
int error = 0;
if (vp->v_mount != dvp->v_mount) {
VOP_ABORTOP(dvp, cnp);
error = EXDEV;
goto out2;
}
if (vp != dvp && (error = VOP_LOCK(vp))) {
VOP_ABORTOP(dvp, cnp);
goto out2;
}
/*
* now that we've locked vp, we have to use out1 instead of out2
*/
if (vp would have too many links) {
VOP_ABORTOP(dvp, cnp);
error = EMLINK;
goto out1;
}
if (vp is immutable) {
VOP_ABORTOP(dvp, cnp);
error = EPERM;
goto out1;
}
/*
* Increment link count of vp and write back the on-disc version of it.
*/
...;
if (!error) {
/*
* Add the new name to the directory.
*/
...;
}
kfree(cnp->cn_pnbuf, M_NAMEI);
out1:
if (vp != dvp)
VOP_UNLOCK(vp);
out2:
return error;
}
ERRORS
[EPERM] the file is immutable
SEE ALSOvnode(9), vn_lock(9)AUTHORS
This man page was originally written by Doug Rabson.
BSD July 24, 1996 BSD
