shithub: gefs

Info  •  Files  •  Log  •  Branches

tree: check for nil block at tail of path

when scanning a tree, we may be at the end of the values,
but not at the end of the messages during our first iter
of the scan; in this case, we don't load up the blocks
in the path, which can lead to a crash. This bug can also
manifest persistently, which can make a file system that's
not corrupt appear scratched.

--- a/tree.c

+++ b/tree.c

@@ -1475,7 +1475,7 @@

 	}

 	for(i = h-2; i >= 0; i--){

-		if(p[i].bi == p[i].b->nbuf)

+		if(p[i].b == nil || p[i].bi == p[i].b->nbuf)

 			continue;

 		getmsg(p[i].b, p[i].bi, &n);

 		if(keycmp(&n, &m) < 0){

@@ -1497,7 +1497,7 @@

 	else

 		p[bufsrc].bi++;

 	for(i = h-2; i >= 0; i--){

-		for(j = p[i].bi; j < p[i].b->nbuf; j++){

+		for(j = p[i].bi; p[i].b != nil && j < p[i].b->nbuf; j++){

 			getmsg(p[i].b, j, &m);

 			if(keycmp(r, &m) != 0)

 				break;