Re: [RESEND PATCH 5/8] maple_tree: make mas_validate_limits() check root node and node limit

[Peng Zhang]

在 2023/7/7 22:58, Liam R. Howlett 写道:
> * Peng Zhang <zhangpeng.00@xxxxxxxxxxxxx> [230707 06:11]:
> > Update mas_validate_limits() to check root node, check node limit pivot
> > if there is enough room for it to exist and check data_end. Remove the
> > check for child existence as it is done in mas_validate_child_slot().
>
> The comments for this function say:
>   * Validate all pivots are within mas->min and mas->max.
>
> This needs adjusting since we are doing a whole lot more now..
Thanks, I will update it in v2.
> Validate limits is now checking metadata ends where the maximum ends,
> checks the pivots are within the limits of the node, and ensures
> there is no slots or pivots set outside of the end of the data.
>
> Did I miss anything?
You're right, that's exactly all the checks it does.
> > Signed-off-by: Peng Zhang <zhangpeng.00@xxxxxxxxxxxxx>
> > ---
> >   lib/maple_tree.c | 26 +++++++++++---------------
> >   1 file changed, 11 insertions(+), 15 deletions(-)
> >
> > diff --git a/lib/maple_tree.c b/lib/maple_tree.c
> > index 88d6373f37b0..e84a042b6d84 100644
> > --- a/lib/maple_tree.c
> > +++ b/lib/maple_tree.c
> > @@ -7148,26 +7148,15 @@ static void mas_validate_limits(struct ma_state *mas)
> >   	void __rcu **slots = ma_slots(mte_to_node(mas->node), type);
> >   	unsigned long *pivots = ma_pivots(mas_mn(mas), type);
> >   
> > -	/* all limits are fine here. */
> > -	if (mte_is_root(mas->node))
> > -		return;
> > -
> >   	for (i = 0; i < mt_slots[type]; i++) {
> >   		unsigned long piv;
> >   
> >   		piv = mas_safe_pivot(mas, pivots, i, type);
> >   
> > -		if (!piv && (i != 0))
> > -			break;
> > -
> > -		if (!mte_is_leaf(mas->node)) {
> > -			void *entry = mas_slot(mas, slots, i);
> > -
> > -			if (!entry)
> > -				pr_err("%p[%u] cannot be null\n",
> > -				       mas_mn(mas), i);
> > -
> > -			MT_BUG_ON(mas->tree, !entry);
> > +		if (!piv && (i != 0)) {
> > +			pr_err("Missing node limit pivot at %p[%u]",
> > +			       mas_mn(mas), i);
> > +			MAS_WARN_ON(mas, 1);
> >   		}
> >   
> >   		if (prev_piv > piv) {
> > @@ -7190,6 +7179,13 @@ static void mas_validate_limits(struct ma_state *mas)
> >   		if (piv == mas->max)
> >   			break;
> >   	}
> > +
> > +	if (mas_data_end(mas) != i) {
> > +		pr_err("node%p: data_end %u != the last slot offset %u\n",
> > +		       mas_mn(mas), mas_data_end(mas), i);
> > +		MT_BUG_ON(mas->tree, 1);
> > +	}
> > +
> >   	for (i += 1; i < mt_slots[type]; i++) {
> >   		void *entry = mas_slot(mas, slots, i);
> >   
> > --
> > 2.20.1
> >
> >
> > --
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