hjfs: dentry qid checking, prevent newentry() from allocating already in use slot

always check if the directory entry qid from the loc still
matches the one on disk before doing anything. helps
catching bugs and is basically equivalent to what cwfs does
with its checktag.

make a haveloc() check in newentry() to make sure we dont
allocate a file slot thats still in use, but deleted.
this seems to fix the NPROC>1 build problems.

sys/src/cmd/hjfs/buf.c

@@ -269,7 +269,8 @@ getbuf(Dev *d, uvlong off, int type, int nodata)
 	if(nodata)
 		b->type = type;
 	if(b->type != type && type != -1){
-		dprint("hjfs: type mismatch, dev %s, block %lld, got %T, want %T, caller %#p\n", d->name, off, b->type, type, getcallerpc(&d));
+		dprint("hjfs: type mismatch, dev %s, block %lld, got %T, want %T, caller %#p\n",
+			d->name, off, b->type, type, getcallerpc(&d));
 		werrstr("phase error -- type mismatch");
 		putbuf(b);
 		return nil;

sys/src/cmd/hjfs/dump.c

@@ -143,8 +143,8 @@ again:
 	p = getbuf(fs->d, l->next->blk, TDENTRY, 0);
 	if(p == nil)
 		goto err;
-	d = &p->de[l->next->deind];
+	d = getdent(l->next, p);
-	for(i = 0; i < d->size; i++){
+	if(d != nil) for(i = 0; i < d->size; i++){
 		rc = getblk(fs, l->next, p, i, &r, GBREAD);
 		if(rc <= 0)
 			continue;

sys/src/cmd/hjfs/fns.h

@@ -8,6 +8,7 @@ void	unpack(Buf *, uchar *);
 Dev*	newdev(char *);
 ThrData*	getthrdata(void);
 Fs*	initfs(Dev *, int, int);
+Dentry*	getdent(FLoc *, Buf *);
 int	getfree(Fs *, uvlong *);
 int	putfree(Fs *, uvlong);
 Chan*	chanattach(Fs *, int);

sys/src/cmd/hjfs/fs1.c

@@ -29,6 +29,35 @@ chref(Fs *fs, uvlong r, int stat)
 	return rc;
 }
 
+static int
+qidcmp(Qid *a, Qid *b)
+{
+	if(a->type != b->type)
+		return 1;
+	if(a->path != b->path)
+		return 1;
+	return 0;
+}
+
+Dentry*
+getdent(FLoc *l, Buf *b)
+{
+	Dentry *d;
+
+	d = &b->de[l->deind];
+	if((d->mode & (DGONE | DALLOC)) == 0){
+		dprint("hjfs: getdent: file gone, callerpc %#p\n", getcallerpc(&l));
+		werrstr("phase error -- getdent");
+		return nil;
+	}
+	if(qidcmp(d, l) != 0){
+		dprint("hjfs: getdent: wrong qid, callerpc %#p\n", getcallerpc(&l));
+		werrstr("phase error -- getdent");
+		return nil;
+	}
+	return d;
+}
+
 int
 getfree(Fs *fs, uvlong *r)
 {
@@ -364,13 +393,13 @@ haveloc(Fs *fs, uvlong blk, int deind, Loc *next)
 
 	qlock(&fs->loctree);
 	l = next->child;
-	do{
+	if(l != nil) do{
 		if(l->blk == blk && l->deind == deind){
 			qunlock(&fs->loctree);
 			return 1;
 		}
 		l = l->cnext;
-	}while(l != next->child);
+	} while(l != next->child);
 	qunlock(&fs->loctree);
 	return 0;
 }
@@ -511,7 +540,11 @@ getblk(Fs *fs, FLoc *L, Buf *bd, uvlong blk, uvlong *r, int mode)
 	Dentry *d;
 
 	b = bd;
-	d = &bd->de[L->deind];
+	d = getdent(L, b);
+	if(d == nil){
+		dprint("hjfs: getblk: dirent gone\n");
+		return -1;
+	}
 	if(blk < NDIRECT){
 		loc = &d->db[blk];
 		goto found;
@@ -696,7 +729,9 @@ trunc(Fs *fs, FLoc *ll, Buf *bd, uvlong size)
 	uvlong l;
 	int i, j;
 
-	d = &bd->de[ll->deind];
+	d = getdent(ll, bd);
+	if(d == nil)
+		return -1;
 	if(size >= d->size)
 		goto done;
 	blk = HOWMANY(size, RBLOCK);
@@ -758,7 +793,9 @@ findentry(Fs *fs, FLoc *l, Buf *b, char *name, FLoc *rl, int dump)
 	uvlong r;
 	Buf *c;
 	
-	d = &b->de[l->deind];
+	d = getdent(l, b);
+	if(d == nil)
+		return -1;
 	for(i = 0; i < d->size; i++){
 		if(getblk(fs, l, b, i, &r, GBREAD) <= 0)
 			continue;
@@ -816,7 +853,10 @@ deltraverse(Fs *fs, Del *p, Buf *b, Del **last)
 		if(b == nil)
 			return -1;
 	}
-	s = b->de[p->deind].size;
+	d = getdent(p, b);
+	if(d == nil)
+		return -1;
+	s = d->size;
 	for(i = 0; i < s; i++){
 		rc = getblk(fs, p, b, i, &r, GBREAD);
 		if(rc <= 0)
@@ -835,6 +875,7 @@ deltraverse(Fs *fs, Del *p, Buf *b, Del **last)
 					dd = emalloc(sizeof(Del));
 					dd->blk = i;
 					dd->deind = j;
+					dd->Qid = d->Qid;
 					dd->prev = *last;
 					(*last)->next = dd;
 					*last = dd;
@@ -855,7 +896,9 @@ delete(Fs *fs, FLoc *l, Buf *b)
 	Buf *c;
 	Del *first, *last, *p, *q;
 
-	d = &b->de[l->deind];
+	d = getdent(l, b);
+	if(d == nil)
+		return -1;
 	if((d->type & QTDIR) == 0){
 		trunc(fs, l, b, 0);
 		memset(d, 0, sizeof(*d));
@@ -873,9 +916,12 @@ delete(Fs *fs, FLoc *l, Buf *b)
 			c = getbuf(fs->d, p->blk, TDENTRY, 0);
 		if(c == nil)
 			continue;
-		trunc(fs, p, c, 0);
+		d = getdent(p, c);
-		memset(&c->de[p->deind], 0, sizeof(Dentry));
+		if(d != nil){
-		c->op |= BDELWRI;
+			trunc(fs, p, c, 0);
+			memset(d, 0, sizeof(*d));
+			c->op |= BDELWRI;
+		}
 		if(p != first)
 			putbuf(c);
 	}
@@ -885,16 +931,16 @@ delete(Fs *fs, FLoc *l, Buf *b)
 int
 newentry(Fs *fs, Loc *l, Buf *b, char *name, FLoc *res)
 {
-	Dentry *d;
+	Dentry *d, *dd;
 	uvlong i, si, r;
 	int j, sj, rc;
 	Buf *c;
 	FLoc f;
 
 	si = sj = -1;
-	d = &b->de[l->deind];
+	d = getdent(l, b);
-	for(i = 0; i <= d->size; i++){
+	if(d != nil) for(i = 0; i <= d->size; i++){
-		if(i == d->size && si != -1)
+		if(i >= d->size && si != -1)
 			break;
 		rc = getblk(fs, l, b, i, &r, si == -1 ? GBCREATE : GBREAD);
 		if(rc < 0)
@@ -906,32 +952,34 @@ newentry(Fs *fs, Loc *l, Buf *b, char *name, FLoc *res)
 			continue;
 		if(rc == 0){
 			memset(c->de, 0, sizeof(c->de));
-			if(i == d->size){
+			if(i >= d->size){
-				d->size++;
+				d->size = i+1;
 				b->op |= BDELWRI;
 			}
 			c->op |= BDELWRI;
 		}
 		for(j = 0; j < DEPERBLK; j++){
-			if(si == -1 && (c->de[j].mode & DALLOC) == 0){
+			dd = &c->de[j];
-				si = i;
+			if((dd->mode & DALLOC) != 0){
-				sj = j;
+				if(strcmp(dd->name, name) == 0){
+					werrstr(Eexists);
+					putbuf(c);
+					return 0;
+				}
+				continue;
 			}
-			if(si == -1 && (c->de[j].mode & DGONE) != 0 && !haveloc(fs, r, j, l)){
+			if(si != -1 || haveloc(fs, r, j, l))
+				continue;
+			if((dd->mode & DGONE) != 0){
 				memset(&f, 0, sizeof(f));
 				f.blk = r;
 				f.deind = j;
-				if(delete(fs, &f, c) >= 0){
+				f.Qid = dd->Qid;
-					si = i;
+				if(delete(fs, &f, c) < 0)
-					sj = j;
+					continue;
-				}
-			}
-			if((c->de[j].mode & DALLOC) != 0 &&
-			   strcmp(c->de[j].name, name) == 0){
-				werrstr(Eexists);
-				putbuf(c);
-				return 0;
 			}
+			si = i;
+			sj = j;
 		}
 		putbuf(c);
 	}
@@ -942,5 +990,6 @@ newentry(Fs *fs, Loc *l, Buf *b, char *name, FLoc *res)
 	if(getblk(fs, l, b, si, &res->blk, GBWRITE) <= 0)
 		return -1;
 	res->deind = sj;
+	res->Qid = (Qid){0, 0, 0};
 	return 1;
 }

sys/src/cmd/hjfs/fs2.c

@@ -53,7 +53,9 @@ chanwalk(Chan *ch, char *name)
 		chend(ch);
 		return -1;
 	}
-	d = &b->de[ch->loc->deind];
+	d = getdent(ch->loc, b);
+	if(d == nil)
+		goto error;
 	if((d->type & QTDIR) == 0){
 		werrstr(Enotadir);
 		goto error;
@@ -132,7 +134,9 @@ chancreat(Chan *ch, char *name, int perm, int mode)
 		chend(ch);
 		return -1;
 	}
-	d = &b->de[ch->loc->deind];
+	d = getdent(ch->loc, b);
+	if(d == nil)
+		goto error;
 	if((d->type & QTDIR) == 0){
 		werrstr(Enotadir);
 		goto error;
@@ -146,9 +150,9 @@ chancreat(Chan *ch, char *name, int perm, int mode)
 	c = getbuf(ch->fs->d, f.blk, TDENTRY, 0);
 	if(c == nil)
 		goto error;
-	c->op |= BDELWRI;
-	b->op |= BDELWRI;
 	modified(ch, d);
+	b->op |= BDELWRI;
+	c->op |= BDELWRI;
 	if(isdir)
 		perm &= ~0777 | d->mode & 0777;
 	else
@@ -213,7 +217,9 @@ chanopen(Chan *ch, int mode)
 		chend(ch);
 		return -1;
 	}
-	d = &b->de[ch->loc->deind];
+	d = getdent(ch->loc, b);
+	if(d == nil)
+		goto err;
 	if(!permcheck(ch->fs, d, ch->uid, mode & OEXEC)){
 	permerr:
 		werrstr(Eperm);
@@ -325,7 +331,12 @@ chanwrite(Chan *ch, void *buf, ulong n, uvlong off)
 		chend(ch);
 		return -1;
 	}
-	d = &b->de[ch->loc->deind];
+	d = getdent(ch->loc, b);
+	if(d == nil){
+		putbuf(b);
+		chend(ch);
+		return -1;
+	}
 	if((d->type & QTAPPEND) != 0)
 		off = d->size;
 	e = off + n;
@@ -392,7 +403,12 @@ chanread(Chan *ch, void *buf, ulong n, uvlong off)
 		chend(ch);
 		return -1;
 	}
-	d = &b->de[ch->loc->deind];
+	d = getdent(ch->loc, b);
+	if(d == nil){
+		putbuf(b);
+		chend(ch);
+		return -1;
+	}
 	if(off >= d->size)
 		n = 0;
 	else if(off + n > d->size)
@@ -465,6 +481,7 @@ int
 chanstat(Chan *ch, Dir *di)
 {
 	Buf *b;
+	Dentry *d;
 	
 	chbegin(ch);
 	b = getbuf(ch->fs->d, ch->loc->blk, TDENTRY, 0);
@@ -472,7 +489,13 @@ chanstat(Chan *ch, Dir *di)
 		chend(ch);
 		return -1;
 	}
-	statbuf(ch->fs, &b->de[ch->loc->deind], di, nil);
+	d = getdent(ch->loc, b);
+	if(d == nil){
+		putbuf(b);
+		chend(ch);
+		return -1;
+	}
+	statbuf(ch->fs, d, di, nil);
 	putbuf(b);
 	chend(ch);
 	return 0;
@@ -504,7 +527,12 @@ chandirread(Chan *ch, void *buf, ulong n, uvlong off)
 		chend(ch);
 		return -1;
 	}
-	d = &b->de[ch->loc->deind];
+	d = getdent(ch->loc, b);
+	if(d == nil){
+		putbuf(b);
+		chend(ch);
+		return -1;
+	}
 	if(ch->dwblk >= d->size){
 		putbuf(b);
 		chend(ch);
@@ -590,11 +618,16 @@ chanclunk(Chan *ch)
 		b = getbuf(ch->fs->d, ch->loc->blk, TDENTRY, 0);
 		if(b == nil)
 			goto err;
-		if(!permcheck(ch->fs, &p->de[ch->loc->next->deind], ch->uid, OWRITE)){
+		d = getdent(ch->loc->next, p);
+		if(d == nil)
+			goto err;
+		if(!permcheck(ch->fs, d, ch->uid, OWRITE)){
 			werrstr(Eperm);
 			goto err;
 		}
-		d = &b->de[ch->loc->deind];
+		d = getdent(ch->loc, b);
+		if(d == nil)
+			goto err;
 		if((d->type & QTDIR) != 0 && findentry(ch->fs, ch->loc, b, nil, nil, ch->flags & CHFDUMP) != 0)
 			goto inval;
 		if((d->mode & DGONE) != 0)
@@ -653,7 +686,10 @@ chanwstat(Chan *ch, Dir *di)
 		pb = getbuf(ch->fs->d, ch->loc->next->blk, TDENTRY, 0);
 		if(pb == nil)
 			goto error;
-		if(!permcheck(ch->fs, &pb->de[ch->loc->next->deind], ch->uid, OWRITE))
+		d = getdent(ch->loc->next, pb);
+		if(d == nil)
+			goto error;
+		if(!permcheck(ch->fs, d, ch->uid, OWRITE))
 			goto perm;
 		rc = findentry(ch->fs, ch->loc->next, pb, di->name, nil, ch->flags & CHFDUMP);
 		if(rc > 0)
@@ -664,7 +700,9 @@ chanwstat(Chan *ch, Dir *di)
 	b = getbuf(ch->fs->d, ch->loc->blk, TDENTRY, 0);
 	if(b == nil)
 		goto error;
-	d = &b->de[ch->loc->deind];
+	d = getdent(ch->loc, b);
+	if(d == nil)
+		goto error;
 	isdir = (d->type & QTDIR) != 0;
 	owner = ch->uid == d->uid || ingroup(ch->fs, ch->uid, d->gid, 1) || (ch->fs->flags & FSNOPERM) != 0;
 	if((uvlong)~di->length){