From b55e6bfcd23cb2f7249095050c649f7aea813f9f Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Mon, 27 Mar 2006 01:18:06 -0800 Subject: [PATCH] md: Split disks array out of raid5 conf structure so it is easier to grow The remainder of this batch implements raid5 reshaping. Currently the only shape change that is supported is added a device, but it is envisioned that changing the chunksize and layout will also be supported, as well as changing the level (e.g. 1->5, 5->6). The reshape process naturally has to move all of the data in the array, and so should be used with caution. It is believed to work, and some testing does support this, but wider testing would be great for increasing my confidence. You will need a version of mdadm newer than 2.3.1 to make use of raid5 growth. This is because mdadm need to take a copy of a 'critical section' at the start of the array incase there is a crash at an awkward moment. On restart, mdadm will restore the critical section and allow reshape to continue. I hope to release a 2.4-pre by early next week - it still needs a little more polishing. This patch: Previously the array of disk information was included in the raid5 'conf' structure which was allocated to an appropriate size. This makes it awkward to change the size of that array. So we split it off into a separate kmalloced array which will require a little extra indexing, but is much easier to grow. Signed-off-by: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/raid/raid5.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/raid') diff --git a/include/linux/raid/raid5.h b/include/linux/raid/raid5.h index 394da8207b34..94dbdd406f12 100644 --- a/include/linux/raid/raid5.h +++ b/include/linux/raid/raid5.h @@ -240,7 +240,7 @@ struct raid5_private_data { * waiting for 25% to be free */ spinlock_t device_lock; - struct disk_info disks[0]; + struct disk_info *disks; }; typedef struct raid5_private_data raid5_conf_t; -- cgit v1.2.2