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 <willy@linux.intel.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Jan Kara <jack@suse.com>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index c0366d1..b3364b9 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.