[dm-devel] [PATCH 1/1] dm raid: fix compat_features validation
Heinz Mauelshagen
heinzm at redhat.com
Tue Oct 11 15:04:34 UTC 2016
Andy,
good catch.
We should rather check for V190 support only in case any
compat feature flags are actually set.
I.e.:
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 8abde6b..2a39700 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -2258,7 +2258,8 @@ static int super_validate(struct raid_set *rs,
struct md_rdev *rdev)
if (!mddev->events && super_init_validation(rs, rdev))
return -EINVAL;
- if (le32_to_cpu(sb->compat_features) !=
FEATURE_FLAG_SUPPORTS_V190) {
+ if (le32_to_cpu(sb->compat_features) &&
+ le32_to_cpu(sb->compat_features) !=
FEATURE_FLAG_SUPPORTS_V190) {
rs->ti->error = "Unable to assemble array: Unknown
flag(s) in compatible feature flags";
return -EINVAL;
}
On 10/11/2016 04:28 PM, Andy Whitcroft wrote:
> In commit ecbfb9f118bce4 ("dm raid: add raid level takeover support") a new
> compatible feature flag was added. Validation for these compat_features
> was added but this only passes for new raid mappings with this feature
> flag. This causes previously created raid mappings to be failed at import.
>
> Check compat_features for any valid combinations.
>
> Fixes: ecbfb9f118bce4 ("dm raid: add raid level takeover support")
> BugLink: http://bugs.launchpad.net/bugs/1631298
> Signed-off-by: Andy Whitcroft <apw at canonical.com>
> ---
> drivers/md/dm-raid.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> It very much looks like these are intended to be optional extended feature
> flags. That we should be accepting any valid flag and rejecting any bit
> not in that set. We should however not be ensuring that specific bits
> are actually set. Certainly as things stand raid sets built on previous
> kernel versions cannot be assembled.
>
> diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
> index 8abde6b..6ddea60 100644
> --- a/drivers/md/dm-raid.c
> +++ b/drivers/md/dm-raid.c
> @@ -2258,7 +2258,7 @@ static int super_validate(struct raid_set *rs, struct md_rdev *rdev)
> if (!mddev->events && super_init_validation(rs, rdev))
> return -EINVAL;
>
> - if (le32_to_cpu(sb->compat_features) != FEATURE_FLAG_SUPPORTS_V190) {
> + if (le32_to_cpu(sb->compat_features) & ~(FEATURE_FLAG_SUPPORTS_V190)) {
> rs->ti->error = "Unable to assemble array: Unknown flag(s) in compatible feature flags";
> return -EINVAL;
> }
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