cwfs: more checking for cfsdump(), cleanup Tsuper hack in cwrecur()

add checktag and nil checks in cfsdump() making sure to notice
when the roroot directory structures is corrupted.

cwrecur() used tag == Tsuper to indicate that this is the first
level recursive invocation. this is confusing as we really expect
Tdir tag in that case for the root directory. instead, we now
pass the correct tag (Tdir) and use cw->depth > 1 to see if we
are past the root.

the block tag was only checked when the block was not in
the memory cache. check the tag always!

1 files changed, 33 insertions, 28 deletions

diff --git a/sys/src/cmd/cwfs/cw.c b/sys/src/cmd/cwfs/cw.c
index 68609c2fb..bba69304c 100644
--- a/sys/src/cmd/cwfs/cw.c
+++ b/sys/src/cmd/cwfs/cw.c
@@ -1331,24 +1331,15 @@ cwrecur(Cw *cw, Off addr, int tag, int tag1, long qp)
 	switch(tag) {
 	default:
 		fprint(2, "cwrecur: unknown tag %d %s\n", tag, cw->name);
+		break;
 
 	case Tfile:
+		if(p && checktag(p, tag, qp))
+			fprint(2, "cwrecur: Tfile %s\n", cw->name);
 		break;
 
-	case Tsuper:
 	case Tdir:
-		if(!p) {
-			p = getbuf(cw->dev, addr, Brd);
-			if(!p || checktag(p, tag, qp)) {
-				fprint(2, "cwrecur: Tdir p null %s\n", cw->name);
-				if(p){
-					putbuf(p);
-					p = nil;
-				}
-				break;
-			}
-		}
-		if(tag == Tdir) {
+		if(cw->depth > 1) {
 			cw->namepad[0] = 0;	/* force room */
 			np = strchr(cw->name, 0);
 			*np++ = '/';
@@ -1356,13 +1347,18 @@ cwrecur(Cw *cw, Off addr, int tag, int tag1, long qp)
 			np = 0;	/* set */
 			cw->name[0] = 0;
 		}
-
+		if(!p)
+			p = getbuf(cw->dev, addr, Brd);
+		if(!p || checktag(p, tag, qp)) {
+			fprint(2, "cwrecur: Tdir %s\n", cw->name);
+			break;
+		}
 		for(i=0; i<DIRPERBUF; i++) {
 			d = getdir(p, i);
 			if((d->mode & (DALLOC|DTMP)) != DALLOC)
 				continue;
 			qp1 = d->qid.path & ~QPDIR;
-			if(tag == Tdir)
+			if(np)
 				strncpy(np, d->name, NAMELEN);
 			else if(i > 0)
 				fprint(2, "cwrecur: root with >1 directory\n");
@@ -1405,16 +1401,11 @@ cwrecur(Cw *cw, Off addr, int tag, int tag1, long qp)
 #endif
 		j = tag-1;
 	tind:
-		if(!p) {
+		if(!p)
 			p = getbuf(cw->dev, addr, Brd);
-			if(!p || checktag(p, tag, qp)) {
-				fprint(2, "cwrecur: Tind p null %s\n", cw->name);
-				if(p){
-					putbuf(p);
-					p = nil;
-				}
-				break;
-			}
+		if(!p || checktag(p, tag, qp)) {
+			fprint(2, "cwrecur: Tind %s\n", cw->name);
+			break;
 		}
 		for(i=0; i<INDPERBUF; i++) {
 			na = ((Off *)p->iobuf)[i];
@@ -1493,7 +1484,7 @@ cfsdump(Filsys *fs)
 	cons.noage = 1;
 	cw->all = cw->allflag | noatime | noatimeset;
 	noatimeset = 0;
-	rba = cwrecur(cw, orba, Tsuper, 0, QPROOT);
+	rba = cwrecur(cw, orba, Tdir, 0, QPROOT);
 	if(rba == 0)
 		rba = orba;
 	if(chatty)
@@ -1504,6 +1495,8 @@ cfsdump(Filsys *fs)
 	 * partial super block
 	 */
 	p = getbuf(cw->dev, cwsaddr(cw->dev), Brd|Bmod|Bimm);
+	if(!p || checktag(p, Tsuper, QPSUPER))
+		goto bad;
 	s = (Superb*)p->iobuf;
 	s->fsize = cw->fsize;
 	s->cwraddr = rba;
@@ -1513,6 +1506,8 @@ cfsdump(Filsys *fs)
 	 * partial cache block
 	 */
 	p = getbuf(cw->cdev, CACHE_ADDR, Brd|Bmod|Bimm|Bres);
+	if(!p || checktag(p, Tcache, QPSUPER))
+		goto bad;
 	h = (Cache*)p->iobuf;
 	h->fsize = cw->fsize;
 	h->cwraddr = rba;
@@ -1523,13 +1518,15 @@ cfsdump(Filsys *fs)
 	 */
 	oroa = cwraddr(cw->rodev);
 	pr = getbuf(cw->dev, oroa, Brd|Bmod);
+	if(!pr || checktag(pr, Tdir, QPROOT))
+		goto bad;
 	dr = getdir(pr, 0);
 
 	datestr(tstr, time(nil));	/* tstr = "yyyymmdd" */
 	n = 0;
 	for(a=0;; a++) {
 		p1 = dnodebuf(pr, dr, a, Tdir, 0);
-		if(!p1)
+		if(!p1 || checktag(p1, Tdir, QPNONE))
 			goto bad;
 		n++;
 		for(i=0; i<DIRPERBUF; i++) {
@@ -1549,6 +1546,8 @@ cfsdump(Filsys *fs)
 	 */
 found1:
 	p = getbuf(cw->dev, rba, Brd);
+	if(!p || checktag(p, Tdir, QPROOT))
+		goto bad;
 	d = getdir(p, 0);
 	d1->qid = d->qid;
 	d1->qid.version += n;
@@ -1572,7 +1571,7 @@ found2:
 	m = 0;
 	for(a=0;; a++) {
 		p1 = dnodebuf(pr, dr, a, Tdir, 0);
-		if(!p1)
+		if(!p1 || checktag(p1, Tdir, QPNONE))
 			goto bad;
 		n++;
 		for(i=0; i<DIRPERBUF; i++) {
@@ -1595,6 +1594,8 @@ found:
 		sprint(tstr+8, "%ld", m);
 
 	p = getbuf(cw->dev, rba, Brd);
+	if(!p || checktag(p, Tdir, QPROOT))
+		goto bad;
 	d = getdir(p, 0);
 	*d1 = *d;				/* qid is QPROOT */
 	putbuf(p);
@@ -1612,7 +1613,7 @@ found:
 
 	cons.noage = 0;
 	cw->all = 0;
-	roa = cwrecur(cw, oroa, Tsuper, 0, QPROOT);
+	roa = cwrecur(cw, oroa, Tdir, 0, QPROOT);
 	if(roa == 0)
 		roa = oroa;
 	if(chatty)
@@ -1626,6 +1627,8 @@ found:
 	if(chatty)
 		fprint(2, "sblock %lld", (Wideoff)a);
 	p = getbuf(cw->dev, a, Brd|Bmod|Bimm);
+	if(!p || checktag(p, Tsuper, QPSUPER))
+		goto bad;
 	s = (Superb*)p->iobuf;
 	s->last = a;
 	sba = s->next;
@@ -1646,6 +1649,8 @@ found:
 	 * final cache block
 	 */
 	p = getbuf(cw->cdev, CACHE_ADDR, Brd|Bmod|Bimm|Bres);
+	if(!p || checktag(p, Tcache, QPSUPER))
+		goto bad;
 	h = (Cache*)p->iobuf;
 	h->fsize = cw->fsize;
 	h->roraddr = roa;