dm btree remove: fix bug in redistribute3

redistribute3() shares entries out across 3 nodes.  Some entries were
being moved the wrong way, breaking the ordering.  This manifested as a
BUG() in dm-btree-remove.c:shift() when entries were removed from the
btree.

For additional context see:
https://www.redhat.com/archives/dm-devel/2015-May/msg00113.html

Signed-off-by: Dennis Yang <shinrairis@gmail.com>
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
This commit is contained in:
Dennis Yang 2015-06-26 15:25:48 +01:00 committed by Mike Snitzer
parent d770e558e2
commit 4c7e309340

View File

@ -309,8 +309,8 @@ static void redistribute3(struct dm_btree_info *info, struct btree_node *parent,
if (s < 0 && nr_center < -s) {
/* not enough in central node */
shift(left, center, nr_center);
s = nr_center - target;
shift(left, center, -nr_center);
s += nr_center;
shift(left, right, s);
nr_right += s;
} else
@ -323,7 +323,7 @@ static void redistribute3(struct dm_btree_info *info, struct btree_node *parent,
if (s > 0 && nr_center < s) {
/* not enough in central node */
shift(center, right, nr_center);
s = target - nr_center;
s -= nr_center;
shift(left, right, s);
nr_left -= s;
} else