From 80b4812407c6b1f66a4f2430e69747a13f010839 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Thu, 27 Sep 2012 12:35:21 +1000 Subject: [PATCH] md/raid10: fix "enough" function for detecting if array is failed. MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The 'enough' function is written to work with 'near' arrays only in that is implicitly assumes that the offset from one 'group' of devices to the next is the same as the number of copies. In reality it is the number of 'near' copies. So change it to make this number explicit. This bug makes it possible to run arrays without enough drives present, which is dangerous. It is appropriate for an -stable kernel, but will almost certainly need to be modified for some of them. Cc: stable@vger.kernel.org Reported-by: Jakub Husák Signed-off-by: NeilBrown --- drivers/md/raid10.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 1c2eb38f3c51..0138a727c1f3 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -1512,14 +1512,16 @@ static int _enough(struct r10conf *conf, struct geom *geo, int ignore) do { int n = conf->copies; int cnt = 0; + int this = first; while (n--) { - if (conf->mirrors[first].rdev && - first != ignore) + if (conf->mirrors[this].rdev && + this != ignore) cnt++; - first = (first+1) % geo->raid_disks; + this = (this+1) % geo->raid_disks; } if (cnt == 0) return 0; + first = (first + geo->near_copies) % geo->raid_disks; } while (first != 0); return 1; } -- 2.20.1