From: NeilBrown Date: Thu, 27 Sep 2012 02:35:21 +0000 (+1000) Subject: md/raid10: fix "enough" function for detecting if array is failed. X-Git-Tag: v3.2.31~62 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4e19de3be14c9390e63271effb5b95ab50f298f4;p=pandora-kernel.git md/raid10: fix "enough" function for detecting if array is failed. commit 80b4812407c6b1f66a4f2430e69747a13f010839 upstream. 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. Reported-by: Jakub Husák Signed-off-by: NeilBrown [bwh: Backported to 3.2: s/geo->/conf->/] Signed-off-by: Ben Hutchings --- diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 7a9eef64c4f9..0634ee5bc3be 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -1226,14 +1226,16 @@ static int enough(struct r10conf *conf, 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) % conf->raid_disks; + this = (this+1) % conf->raid_disks; } if (cnt == 0) return 0; + first = (first + conf->near_copies) % conf->raid_disks; } while (first != 0); return 1; }