radix-tree: fix deleting a multi-order entry through an alias

If we deleted an entry through an index which looked up a sibling
pointer, we'd end up zeroing out the wrong slots in the node.  Use
get_slot_offset() to find the right slot.

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]>

diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index c0366d1d2613e788f07a46f1224fff99d94bef80..b3364b9ecc839208c2226ddd3e32b950c40ea035 100644 (file)
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -1558,7 +1558,7 @@ void *radix_tree_delete_item(struct radix_tree_root *root,
                return entry;
        }
 
-       offset = index & RADIX_TREE_MAP_MASK;
+       offset = get_slot_offset(node, slot);
 
        /*
         * Clear all tags associated with the item to be deleted.