Re: [RESEND PATCH 3/8] maple_tree: make mas_validate_gaps() to check metadata

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 





在 2023/7/7 22:45, Liam R. Howlett 写道:
* Peng Zhang <zhangpeng.00@xxxxxxxxxxxxx> [230707 06:11]:
Make mas_validate_gaps() check whether the offset in the metadata points
to the largest gap. By the way, simplify this function.

Signed-off-by: Peng Zhang <zhangpeng.00@xxxxxxxxxxxxx>
---
  lib/maple_tree.c | 68 +++++++++++++++++++++++-------------------------
  1 file changed, 33 insertions(+), 35 deletions(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 6a8982146338..1fe8b6a787dd 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -6983,15 +6983,16 @@ EXPORT_SYMBOL_GPL(mt_dump);
  static void mas_validate_gaps(struct ma_state *mas)
  {
  	struct maple_enode *mte = mas->node;
-	struct maple_node *p_mn;
+	struct maple_node *p_mn, *node = mte_to_node(mte);
+	enum maple_type mt = mte_node_type(mas->node);
  	unsigned long gap = 0, max_gap = 0;
  	unsigned long p_end, p_start = mas->min;
-	unsigned char p_slot;
+	unsigned char p_slot, offset;
  	unsigned long *gaps = NULL;
-	unsigned long *pivots = ma_pivots(mte_to_node(mte), mte_node_type(mte));
+	unsigned long *pivots = ma_pivots(node, mt);
  	int i;
- if (ma_is_dense(mte_node_type(mte))) {
+	if (ma_is_dense(mt)) {
  		for (i = 0; i < mt_slot_count(mte); i++) {
  			if (mas_get_slot(mas, i)) {
  				if (gap > max_gap)
@@ -7004,52 +7005,51 @@ static void mas_validate_gaps(struct ma_state *mas)
  		goto counted;
  	}
- gaps = ma_gaps(mte_to_node(mte), mte_node_type(mte));
+	gaps = ma_gaps(node, mt);
  	for (i = 0; i < mt_slot_count(mte); i++) {
-		p_end = mas_logical_pivot(mas, pivots, i, mte_node_type(mte));
+		p_end = mas_logical_pivot(mas, pivots, i, mt);
if (!gaps) {
-			if (mas_get_slot(mas, i)) {
-				gap = 0;
-				goto not_empty;
-			}
-
-			gap += p_end - p_start + 1;
+			if (!mas_get_slot(mas, i))
+				gap = p_end - p_start + 1;
  		} else {
  			void *entry = mas_get_slot(mas, i);
gap = gaps[i];
-			if (!entry) {
-				if (gap != p_end - p_start + 1) {
-					pr_err("%p[%u] -> %p %lu != %lu - %lu + 1\n",
-						mas_mn(mas), i,
-						mas_get_slot(mas, i), gap,
-						p_end, p_start);
-					mt_dump(mas->tree, mt_dump_hex);
-
-					MT_BUG_ON(mas->tree,
-						gap != p_end - p_start + 1);
-				}
-			} else {
-				if (gap > p_end - p_start + 1) {
-					pr_err("%p[%u] %lu >= %lu - %lu + 1 (%lu)\n",
-					mas_mn(mas), i, gap, p_end, p_start,
-					p_end - p_start + 1);
-					MT_BUG_ON(mas->tree,
-						gap > p_end - p_start + 1);
-				}
+			MT_BUG_ON(mas->tree, !entry);
+
+			if (gap > p_end - p_start + 1) {
+				pr_err("%p[%u] %lu >= %lu - %lu + 1 (%lu)\n",
+				mas_mn(mas), i, gap, p_end, p_start,
+				p_end - p_start + 1);
+				MT_BUG_ON(mas->tree,
+					gap > p_end - p_start + 1);

Your change above points out that we are not verifying all gaps are zero
in non-leaf nodes after p_end >= mas->max.  If we don't have a 'no gap'
indicator then this may be an issue, or maybe it already is an issue?
If we don't have a 'no gap' indicator, why is there an issue? Are you
worried that meta_gap is wrongly pointing to the gap after the node
limit? If so we can verify that meta_gap points to a gap within the node
limit.

  			}
  		}
if (gap > max_gap)
  			max_gap = gap;
-not_empty:
+
  		p_start = p_end + 1;
  		if (p_end >= mas->max)
  			break;
  	}
counted:
+	if (mt == maple_arange_64) {

We could loop through the remainder of the gaps here pretty easily.
In this way, it can be verified that the gaps after the node limit are
0.


+		offset = ma_meta_gap(node, mt);
+		if (offset > mt_slots[mt]) {
+			pr_err("gap offset %p[%u] is invalid\n", node, offset);
+			MT_BUG_ON(mas->tree, 1);
+		}
+
+		if (gaps[offset] != max_gap) {
+			pr_err("gap %p[%u] is not the largest gap %lu\n",
+			       node, offset, max_gap);
+			MT_BUG_ON(mas->tree, 1);
+		}
+	}
+
  	if (mte_is_root(mte))
  		return;
@@ -7059,10 +7059,8 @@ static void mas_validate_gaps(struct ma_state *mas)
  	if (ma_gaps(p_mn, mas_parent_type(mas, mte))[p_slot] != max_gap) {
  		pr_err("gap %p[%u] != %lu\n", p_mn, p_slot, max_gap);
  		mt_dump(mas->tree, mt_dump_hex);
+		MT_BUG_ON(mas->tree, 1);
  	}
-
-	MT_BUG_ON(mas->tree,
-		  ma_gaps(p_mn, mas_parent_type(mas, mte))[p_slot] != max_gap);
  }
static void mas_validate_parent_slot(struct ma_state *mas)
--
2.20.1


--
maple-tree mailing list
maple-tree@xxxxxxxxxxxxxxxxxxx
https://lists.infradead.org/mailman/listinfo/maple-tree




[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux OMAP]     [Linux MIPS]     [eCos]     [Asterisk Internet PBX]     [Linux API]

  Powered by Linux