On Mon 04-11-13 15:26:38, Jan Kara wrote:
> On Fri 01-11-13 15:38:50, Cody P Schafer wrote:
> > Use rbtree_postorder_for_each_entry_safe() to destroy the rbtree instead
> > of opencoding an alternate postorder iteration that modifies the tree
>   Thanks. I've merged the patch into my tree.
  Hum, except that the kernel oopses with this patch. And I think the
problem is in rbtree_postorder_for_each_entry_safe(). How are those tests
for NULL supposed to work? For example if the tree is empty, 'pos' will be
NULL and you'll call rb_next_postorder(&NULL->field) which is pretty much
guaranteed to oops if 'field' doesn't have offset 0 in the structure...
        
                                                                Honza

> > Signed-off-by: Cody P Schafer <c...@linux.vnet.ibm.com>
> > ---
> >  fs/ext3/dir.c | 36 +++++-------------------------------
> >  1 file changed, 5 insertions(+), 31 deletions(-)
> > 
> > diff --git a/fs/ext3/dir.c b/fs/ext3/dir.c
> > index bafdd48..a331ad1 100644
> > --- a/fs/ext3/dir.c
> > +++ b/fs/ext3/dir.c
> > @@ -309,43 +309,17 @@ struct fname {
> >   */
> >  static void free_rb_tree_fname(struct rb_root *root)
> >  {
> > -   struct rb_node  *n = root->rb_node;
> > -   struct rb_node  *parent;
> > -   struct fname    *fname;
> > -
> > -   while (n) {
> > -           /* Do the node's children first */
> > -           if (n->rb_left) {
> > -                   n = n->rb_left;
> > -                   continue;
> > -           }
> > -           if (n->rb_right) {
> > -                   n = n->rb_right;
> > -                   continue;
> > -           }
> > -           /*
> > -            * The node has no children; free it, and then zero
> > -            * out parent's link to it.  Finally go to the
> > -            * beginning of the loop and try to free the parent
> > -            * node.
> > -            */
> > -           parent = rb_parent(n);
> > -           fname = rb_entry(n, struct fname, rb_hash);
> > +   struct fname *fname, *next;
> > +
> > +   rbtree_postorder_for_each_entry_safe(fname, next, root, rb_hash)
> >             while (fname) {
> >                     struct fname * old = fname;
> >                     fname = fname->next;
> >                     kfree (old);
> >             }
> > -           if (!parent)
> > -                   *root = RB_ROOT;
> > -           else if (parent->rb_left == n)
> > -                   parent->rb_left = NULL;
> > -           else if (parent->rb_right == n)
> > -                   parent->rb_right = NULL;
> > -           n = parent;
> > -   }
> > -}
> >  
> > +   *root = RB_ROOT;
> > +}
> >  
> >  static struct dir_private_info *ext3_htree_create_dir_info(struct file 
> > *filp,
> >                                                        loff_t pos)
> > -- 
> > 1.8.4.2
> > 
> -- 
> Jan Kara <j...@suse.cz>
> SUSE Labs, CR
-- 
Jan Kara <j...@suse.cz>
SUSE Labs, CR
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