mm gang: you goofed!

[Hugh Dickins]

I've not actually seen truncate_inode_pages' "I goofed!" message
(except when I added further debug to cover lstart != 0 truncation,
which fsx is keen on), but I think it could occur even in that case.

It seems that __lookup() can easily return 0, even though there's
more to find, if it starts partway into a RADIX_TREE_MAP_SIZE
array, in which the only occupied slots are before it starts.

Patch below seems to fix it, but I bet you can improve upon it.

Might this relate to Trond/Chuck's NFS invalidation woes?
It's certainly the main contributor to my tmpfs problems.

I look forward to your "erk" - or will you delight us with
some other exclamation?!

Hugh

--- 2.5.36-mm1/lib/radix-tree.c	Tue Sep 17 11:04:08 2002
+++ linux/lib/radix-tree.c	Wed Sep 18 19:46:10 2002
@@ -231,8 +231,6 @@ __lookup(struct radix_tree_root *root, v
 	unsigned int height = root->height;
 	struct radix_tree_node *slot;
 
-	if (index > max_index)
-		return 0;
 	shift = (height-1) * RADIX_TREE_MAP_SHIFT;
 	slot = root->rnode;
 
@@ -307,9 +305,11 @@ radix_tree_gang_lookup(struct radix_tree
 		unsigned int nr_found;
 		unsigned long next_index;	/* Index of next search */
 
+		if (cur_index > max_index)
+			break;
 		nr_found = __lookup(root, results + ret, cur_index,
 				max_items - ret, &next_index, max_index);
-		if (nr_found == 0)
+		if (nr_found == 0 && !(cur_index & RADIX_TREE_MAP_MASK))
 			break;
 		ret += nr_found;
 		cur_index = next_index;