radix-tree: fix multiorder BUG_ON in radix_tree_insert

These BUG_ON tests are to ensure that all the tags are clear when
inserting a new entry.  If we insert a multiorder entry, we'll end up
looking at the tags for a different node, and so the BUG_ON can end up
triggering spuriously.

Also, we now have three tags, not two, so check all three are clear, and
check all the root tags with a single call to BUG_ON since the bits are
stored contiguously.

Include a test-case to ensure this problem does not reoccur.

Signed-off-by: Matthew Wilcox <[email protected]>
Reviewed-by: Ross Zwisler <[email protected]>
Cc: Konstantin Khlebnikov <[email protected]>
Cc: Kirill Shutemov <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Neil Brown <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 12 insertions, 0 deletions

diff --git a/tools/testing/radix-tree/multiorder.c b/tools/testing/radix-tree/multiorder.c
index 71f34a047002..0a311a5f39de 100644
--- a/tools/testing/radix-tree/multiorder.c
+++ b/tools/testing/radix-tree/multiorder.c
@@ -81,6 +81,17 @@ static void multiorder_shrink(unsigned long index, int order)
 		item_check_absent(&tree, i);
 }
 
+static void multiorder_insert_bug(void)
+{
+	RADIX_TREE(tree, GFP_KERNEL);
+
+	item_insert(&tree, 0);
+	radix_tree_tag_set(&tree, 0, 0);
+	item_insert_order(&tree, 3 << 6, 6);
+
+	item_kill_tree(&tree);
+}
+
 void multiorder_checks(void)
 {
 	int i;
@@ -94,4 +105,5 @@ void multiorder_checks(void)
 	for (i = 0; i < 15; i++)
 		multiorder_shrink((1UL << (i + RADIX_TREE_MAP_SHIFT)), i);
 
+	multiorder_insert_bug();
 }