Provided by: freebsd-manpages_7.0-2_all bug

NAME

     VOP_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 should not be released on exit because it is done by
     the caller.  The directory and file vnodes should not be released on
     exit.

LOCKS

     VOP_LINK() expects the directory and file vnodes to be locked on entry
     and will leave the vnodes locked on return.

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)
             return (EXDEV);

         if (vp would have too many links)
             return (EMLINK);

         if (vp is immutable)
             return (EPERM);

         /*
          * Increment link count of vp and write back the on-disc version of it.
          */
         ...;

         if (!error) {
             /*
              * Add the new name to the directory.
              */
             ...;
         }

         return error;
     }

ERRORS

     [EMLINK]           The file has too many links.

     [EPERM]            The file is immutable.

     [EXDEV]            A hard link is not possible between different file
                        systems.

SEE ALSO

     vn_lock(9), vnode(9)

AUTHORS

     This manual page was originally written by Doug Rabson.