From: Neil Brown Date: Wed, 7 Jan 2009 07:55:39 +0000 (+0100) Subject: block: fix bug in ptbl lookup cache X-Git-Tag: v2.6.29-rc1~28^2 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=54b0d127696aba2ef1ec5430301c968ab539fa0d;p=linux-2.6-omap-h63xx.git block: fix bug in ptbl lookup cache Neil writes: Hi Jens, I've found a little bug for you. It was introduced by a6f23657d3072bde6844055bbc2290e497f33fbc block: add one-hit cache for disk partition lookup and has the effect of killing my machine whenever I try to assemble an md array :-( One of the devices in the array has partitions, and mdadm always deletes partitions before putting a whole-device in an array (as it can cause confusion). The next IO to that device locks the machine. I don't really understand exactly why it locks up, but it happens in disk_map_sector_rcu(). This patch fixes it. Which is due to a missing clear of the (now) stale partition lookup data. So clear that when we delete a partition. Signed-off-by: Jens Axboe --- diff --git a/fs/partitions/check.c b/fs/partitions/check.c index 5198ada6739..6d720243f5f 100644 --- a/fs/partitions/check.c +++ b/fs/partitions/check.c @@ -334,6 +334,7 @@ void delete_partition(struct gendisk *disk, int partno) blk_free_devt(part_devt(part)); rcu_assign_pointer(ptbl->part[partno], NULL); + rcu_assign_pointer(ptbl->last_lookup, NULL); kobject_put(part->holder_dir); device_del(part_to_dev(part));