From 02e5f5c0a0f726e66e3d8506ea1691e344277969 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Thu, 14 Nov 2013 15:16:15 +1100 Subject: [PATCH] md: fix calculation of stacking limits on level change. The various ->run routines of md personalities assume that the 'queue' has been initialised by the blk_set_stacking_limits() call in md_alloc(). However when the level is changed (by level_store()) the ->run routine for the new level is called for an array which has already had the stacking limits modified. This can result in incorrect final settings. So call blk_set_stacking_limits() before ->run in level_store(). A specific consequence of this bug is that it causes discard_granularity to be set incorrectly when reshaping a RAID4 to a RAID0. This is suitable for any -stable kernel since 3.3 in which blk_set_stacking_limits() was introduced. Cc: stable@vger.kernel.org (3.3+) Reported-and-tested-by: "Baldysiak, Pawel" Signed-off-by: NeilBrown --- drivers/md/md.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/md/md.c b/drivers/md/md.c index 2445fece9263..1975c2d7aba3 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -3620,6 +3620,7 @@ level_store(struct mddev *mddev, const char *buf, size_t len) mddev->in_sync = 1; del_timer_sync(&mddev->safemode_timer); } + blk_set_stacking_limits(&mddev->queue->limits); pers->run(mddev); set_bit(MD_CHANGE_DEVS, &mddev->flags); mddev_resume(mddev);