radix-tree: fix bug when erasing elts in remove_prefix

_erase_elt() now zeroes the last element of the array (ie. sets to UNSET). Previously remove() was doing this, but not remove_prefix().
lvmteam · Jun 21, 2018 · 72e2e92 · 72e2e92
1 parent 40c1f78
commit 72e2e92
Showing 1 changed file with 6 additions and 6 deletions.
diff --git a/base/data-struct/radix-tree.c b/base/data-struct/radix-tree.c
@@ -626,6 +626,9 @@ static void _erase_elt(void *array, unsigned obj_size, unsigned count, unsigned
  memmove(((uint8_t *) array) + (obj_size * index),
  ((uint8_t *) array) + (obj_size * (index + 1)),
  obj_size * (count - index - 1));
+
+ // Zero the now unused last elt (set's v.type to UNSET)
+ memset(array + (count - 1) * obj_size, 0, obj_size);
 }
 
 static bool _remove(struct radix_tree *rt, struct value *root, uint8_t *kb, uint8_t *ke)
@@ -700,7 +703,6 @@ static bool _remove(struct radix_tree *rt, struct value *root, uint8_t *kb, uint
  }
 
  n4->nr_entries--;
- n4->values[n4->nr_entries].type = UNSET;
  if (!n4->nr_entries) {
  free(n4);
  root->type = UNSET;
@@ -723,7 +725,6 @@ static bool _remove(struct radix_tree *rt, struct value *root, uint8_t *kb, uint
  }
 
  n16->nr_entries--;
- n16->values[n16->nr_entries].type = UNSET;
  if (n16->nr_entries <= 4) {
  _degrade_to_n4(n16, root);
  }
@@ -745,7 +746,6 @@ static bool _remove(struct radix_tree *rt, struct value *root, uint8_t *kb, uint
  n48->keys[j]--;
  _erase_elt(n48->values, sizeof(*n48->values), n48->nr_entries, i);
  n48->nr_entries--;
- n48->values[n48->nr_entries].type = UNSET;
  if (n48->nr_entries <= 16)
  _degrade_to_n16(n48, root);
  }
@@ -1066,7 +1066,7 @@ static bool _check_nodes(struct value *v, unsigned *count)
 
  for (i = n4->nr_entries; i < 4; i++)
  if (n4->values[i].type != UNSET) {
- fprintf(stderr, "unused value is not UNSET\n");
+ fprintf(stderr, "unused value is not UNSET (n4)\n");
  return false;
  }
 
@@ -1080,7 +1080,7 @@ static bool _check_nodes(struct value *v, unsigned *count)
 
  for (i = n16->nr_entries; i < 16; i++)
  if (n16->values[i].type != UNSET) {
- fprintf(stderr, "unused value is not UNSET\n");
+ fprintf(stderr, "unused value is not UNSET (n16)\n");
  return false;
  }
 
@@ -1105,7 +1105,7 @@ static bool _check_nodes(struct value *v, unsigned *count)
 
  for (i = n48->nr_entries; i < 48; i++)
  if (n48->values[i].type != UNSET) {
- fprintf(stderr, "unused value is not UNSET\n");
+ fprintf(stderr, "unused value is not UNSET (n48)\n");
  return false;
  }