[PATCH] bug in radix_tree_delete

[Dave Kleikamp]

I was looking through the radix tree code and came across what I think
is a bug in radix_tree_delete.

	for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) {
		if (pathp[0].node->tags[tag][idx]) {
			tags[tag] = 1;
			nr_cleared_tags--;
			break;
		}
	}

The above loop should only be executed if tags[tag] is zero.  Otherwise,
when walking up the tree, we can decrement nr_cleared_tags twice or more
for the same value of tag, thus potentially exiting the outer loop too
early.

radix-tree: Ensure that nr_cleared_tags is only decremented once for each tag.

Signed-off-by: Dave Kleikamp <shaggy@xxxxxxxxxxxxxx>
diff -Nurp linux-2.6.10-rc1-mm4/lib/radix-tree.c linux/lib/radix-tree.c
--- linux-2.6.10-rc1-mm4/lib/radix-tree.c	2004-11-10 14:45:18.259269000 -0600
+++ linux/lib/radix-tree.c	2004-11-10 14:45:59.292031072 -0600
@@ -725,8 +725,10 @@ void *radix_tree_delete(struct radix_tre
 		for (tag = 0; tag < RADIX_TREE_TAGS; tag++) {
 			int idx;
 
-			if (!tags[tag])
-				tag_clear(pathp[0].node, tag, pathp[0].offset);
+			if (tags[tag])
+				continue;
+
+			tag_clear(pathp[0].node, tag, pathp[0].offset);
 
 			for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) {
 				if (pathp[0].node->tags[tag][idx]) {


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