+ error = iupdat(ip, &time, &time, 1);
+ IUNLOCK(ip);
+
+ /*
+ * When the target exists, both the directory
+ * and target vnodes are returned locked.
+ */
+ dp = VTOI(tndp->ni_dvp);
+ xp = NULL;
+ if (tndp->ni_vp)
+ xp = VTOI(tndp->ni_vp);
+ /*
+ * If ".." must be changed (ie the directory gets a new
+ * parent) then the source directory must not be in the
+ * directory heirarchy above the target, as this would
+ * orphan everything below the source directory. Also
+ * the user must have write permission in the source so
+ * as to be able to change "..". We must repeat the call
+ * to namei, as the parent directory is unlocked by the
+ * call to checkpath().
+ */
+ if (oldparent != dp->i_number)
+ newparent = dp->i_number;
+ if (doingdirectory && newparent) {
+ if (error = iaccess(ip, IWRITE, tndp->ni_cred))
+ goto bad;
+ tndp->ni_nameiop = RENAME | LOCKPARENT | LOCKLEAF | NOCACHE;
+ do {
+ dp = VTOI(tndp->ni_dvp);
+ if (xp != NULL)
+ iput(xp);
+ if (error = checkpath(ip, dp, tndp->ni_cred))
+ goto out;
+ if (error = namei(tndp))
+ goto out;
+ xp = NULL;
+ if (tndp->ni_vp)
+ xp = VTOI(tndp->ni_vp);
+ } while (dp != VTOI(tndp->ni_dvp));
+ }
+ /*
+ * 2) If target doesn't exist, link the target
+ * to the source and unlink the source.
+ * Otherwise, rewrite the target directory
+ * entry to reference the source inode and
+ * expunge the original entry's existence.
+ */
+ if (xp == NULL) {
+ if (dp->i_dev != ip->i_dev)
+ panic("rename: EXDEV");
+ /*
+ * Account for ".." in new directory.
+ * When source and destination have the same
+ * parent we don't fool with the link count.
+ */
+ if (doingdirectory && newparent) {
+ dp->i_nlink++;
+ dp->i_flag |= ICHG;
+ error = iupdat(dp, &time, &time, 1);
+ }
+ if (error = direnter(ip, tndp))
+ goto out;
+ } else {
+ if (xp->i_dev != dp->i_dev || xp->i_dev != ip->i_dev)
+ panic("rename: EXDEV");
+ /*
+ * Short circuit rename(foo, foo).
+ */
+ if (xp->i_number == ip->i_number)
+ panic("rename: same file");
+ /*
+ * If the parent directory is "sticky", then the user must
+ * own the parent directory, or the destination of the rename,
+ * otherwise the destination may not be changed (except by
+ * root). This implements append-only directories.
+ */
+ if ((dp->i_mode & ISVTX) && tndp->ni_cred->cr_uid != 0 &&
+ tndp->ni_cred->cr_uid != dp->i_uid &&
+ xp->i_uid != tndp->ni_cred->cr_uid) {
+ error = EPERM;
+ goto bad;
+ }
+ /*
+ * Target must be empty if a directory
+ * and have no links to it.
+ * Also, insure source and target are
+ * compatible (both directories, or both
+ * not directories).
+ */
+ if ((xp->i_mode&IFMT) == IFDIR) {
+ if (!dirempty(xp, dp->i_number, tndp->ni_cred) ||
+ xp->i_nlink > 2) {
+ error = ENOTEMPTY;
+ goto bad;
+ }
+ if (!doingdirectory) {
+ error = ENOTDIR;
+ goto bad;
+ }
+ cache_purge(ITOV(dp));
+ } else if (doingdirectory) {
+ error = EISDIR;
+ goto bad;
+ }
+ if (error = dirrewrite(dp, ip, tndp))
+ goto bad;
+ vput(ITOV(dp));
+ /*
+ * Adjust the link count of the target to
+ * reflect the dirrewrite above. If this is
+ * a directory it is empty and there are
+ * no links to it, so we can squash the inode and
+ * any space associated with it. We disallowed
+ * renaming over top of a directory with links to
+ * it above, as the remaining link would point to
+ * a directory without "." or ".." entries.
+ */
+ xp->i_nlink--;
+ if (doingdirectory) {
+ if (--xp->i_nlink != 0)
+ panic("rename: linked directory");
+ error = itrunc(xp, (u_long)0);
+ }
+ xp->i_flag |= ICHG;