From 3a0f9aaee02857609d79b20c809c02a8b7c39d06 Mon Sep 17 00:00:00 2001
From: Jonathan Brassow <jbrassow@redhat.com>
Date: Fri, 21 Dec 2012 20:23:33 +0000
Subject: [PATCH] dm raid: round region_size to power of two
If the user does not supply a bitmap region_size to the dm raid target,
a reasonable size is computed automatically. If this is not a power of 2,
the md code will report an error later.
This patch catches the problem early and rounds the region_size to the
next power of two.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
---
drivers/md/dm-raid.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 45d94a7e7f6db7..4a20bf8c72da66 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -295,9 +295,11 @@ static int validate_region_size(struct raid_set *rs, unsigned long region_size)
* Choose a reasonable default. All figures in sectors.
*/
if (min_region_size > (1 << 13)) {
+ /* If not a power of 2, make it the next power of 2 */
+ if (min_region_size & (min_region_size - 1))
+ region_size = 1 << fls(region_size);
DMINFO("Choosing default region size of %lu sectors",
region_size);
- region_size = min_region_size;
} else {
DMINFO("Choosing default region size of 4MiB");
region_size = 1 << 13; /* sectors */
--
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