From 0ca69886a8273ac1350143d562280bfcbe4760dc Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Fri, 14 Jan 2011 09:14:33 +1100 Subject: md: Ensure no IO request to get md device before it is properly initialised. When an md device is in the process of coming on line it is possible for an IO request (typically a partition table probe) to get through before the array is fully initialised, which can cause unexpected behaviour (e.g. a crash). So explicitly record when the array is ready for IO and don't allow IO through until then. There is no possibility for a similar problem when the array is going off-line as there must only be one 'open' at that time, and it is busy off-lining the array and so cannot send IO requests. So no memory barrier is needed in md_stop() This has been a bug since commit 409c57f3801 in 2.6.30 which introduced md_make_request. Before then, each personality would register its own make_request_fn when it was ready. This is suitable for any stable kernel from 2.6.30.y onwards. Cc: Signed-off-by: NeilBrown Reported-by: "Hawrylewicz Czarnowski, Przemyslaw" --- drivers/md/md.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/md/md.h') diff --git a/drivers/md/md.h b/drivers/md/md.h index d05bab55df4e..229675a604f7 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -148,7 +148,8 @@ struct mddev_s * are happening, so run/ * takeover/stop are not safe */ - + int ready; /* See when safe to pass + * IO requests down */ struct gendisk *gendisk; struct kobject kobj; -- cgit v1.2.3