#include "lib9.h"#include "logfs.h"#include "fcall.h"#include "local.h" char *logfsserverwalk(LogfsServer *server, u32int fid, u32int newfid, ushort nwname, char **wname, ushort *nwqid, Qid *wqid){	ushort i;	Entry *e;	char *errmsg;	Fid *f;	if(server->trace > 1) {		print("logfsserverwalk(%ud, %ud, %ud, \"", fid, newfid, nwname);		for(i = 0; i < nwname; i++) {			if(i > 0)				print("/");			print("%s", wname[i]);		}		print("\")\n");	}	f = logfsfidmapfindentry(server->fidmap, fid);	if(f == nil)		return logfsebadfid;	if(f->openmode >= 0)		return logfsefidopen;	errmsg = nil;	e = f->entry;	if(e->deadandgone)		return Eio;	for(i = 0; i < nwname; i++) {		Entry *se;		/*		 * deal with ..		 */		if(strcmp(wname[i], "..") == 0)			se = e->parent;		else if(strcmp(wname[i], ".") == 0)			se = e;		else {			/*			 * is it a directory?			 */			if((e->qid.type & QTDIR) == 0) {				errmsg = Enotdir;				break;			}			/*			 * can we walk the walk, or just talk the protocol?			 */			if(!logfsuserpermcheck(server, e, f, DMEXEC)) {				errmsg = Eperm;				break;			}			/*			 * search current entry for nwname[i]			 */			for(se = e->u.dir.list; se; se = se->next)				if(strcmp(se->name, wname[i]) == 0)					break;			if(se == nil) {				errmsg = Enonexist;				break;			}		}		wqid[i] = se->qid;		e = se;	}	if(nwname > 0 && i == 0) {		/*		 * fell at the first fence		 */		return errmsg;	}	*nwqid = i;	if(i < nwname)		return nil;	/*	 * new fid required?	 */	if(fid != newfid) {		Fid *newf;		char *errmsg;		errmsg = logfsfidmapnewentry(server->fidmap, newfid, &newf);		if(errmsg)			return errmsg;		if(newf == nil)			return logfsefidinuse;		newf->entry = e;		newf->uname = f->uname;		e->inuse++;	}	else {		/*		 * this may now be right		 * 1. increment reference on new entry first in case e and f->entry are the same		 * 2. clunk the old one in case this has the effect of removing an old entry		 * 3. dump the directory read state if the entry has changed		 */		e->inuse++;		logfsentryclunk(f->entry);		if(e != f->entry)			logfsdrsfree(&f->drs);		f->entry = e;	}	return nil;}