RE: mdadm(IMSM): Unsupported attributes : 40000000

["Wojcik, Krzysztof" <krzysztof.wojcik@intel.com>]

Neil,

In fact this bit may cause backward compatibility issue.
It was used in old versions of IMSM metadata and for some reason was marked as "never use".
Skipping this bit during compatibility check is good idea.

I've checked compatibility with metadata created using dmraid and got another issue.
Attribute "MPB_ATTRIB_NEVER_USE2" is set in metadata created by dmraid so mdadm refuse loading metadata.
Could you add MPB_ATTRIB_NEVER_USE2 to your patch to MPB_ATTRIB_IGNORED list?

Regards
Krzysztof

> -----Original Message-----
> From: NeilBrown [mailto:neilb@suse.de]
> Sent: Tuesday, August 09, 2011 12:51 AM
> To: Thomas Steinborn
> Cc: linux-raid@vger.kernel.org; Kwolek, Adam; Wojcik, Krzysztof;
> Williams, Dan J
> Subject: Re: mdadm(IMSM): Unsupported attributes : 40000000
> 
> On Sat, 6 Aug 2011 20:55:47 +0200 Thomas Steinborn
> <thestonewell@googlemail.com> wrote:
> 
> > Hi,
> >
> > after updating to mdadm 3.2.2 (by way of upgrading from Fedora 14 to
> > 15) from 3.1.5 I am no longer able to boot my IMSM raid, which I was
> > able to for the last 5 years or so.
> >
> > The errors I am getting are:
> >
> >   mdadm(IMSM): Unsupported attributes : 40000000
> >   mdadm: IMSM metadata loading not allowed due to attributes
> incompatibility.
> >
> > I tracked that down to the patch at
> >
> > http://www.spinics.net/lists/raid/msg34783.html
> >
> > According to that patch 40000000 means #define MPB_ATTRIB_NEVER_USE
> > __cpu_to_le32(0x40000000). Any advice why an unused but aparently set
> > attribute should stop the raid to boot?
> >
> > For now I am up and running with 3.1.5 but would like to keep up with
> > the latest mdadm if possible.
> >
> > Thanks
> > Thomas
> > --
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> 
> Thanks for the report.
> 
> It looks like we need something like the following.
> 
> Adam/Kryzysztof:  Is this patch reasonable?
> 
> Thanks,
> NeilBrown
> 
> 
> 
> 
> 
> From 418f9b368a1200370695527d22aba8c3606172c5 Mon Sep 17 00:00:00 2001
> From: NeilBrown <neilb@suse.de>
> Date: Tue, 9 Aug 2011 08:49:34 +1000
> Subject: [PATCH] IMSM: allow some array attribute bits to be ignored.
> 
> Some bits are not handled by mdadm, but their presence should not
> cause failure.
> In particular MPB_ATTRIB_NEVER_USE appears harmless.
> 
> Reported-by: Thomas Steinborn <thestonewell@googlemail.com>
> Signed-off-by: NeilBrown <neilb@suse.de>
> 
> diff --git a/super-intel.c b/super-intel.c
> index dcab5f9..ddf4de9 100644
> --- a/super-intel.c
> +++ b/super-intel.c
> @@ -74,14 +74,17 @@
> 
>  /* Define all supported attributes that have to be accepted by mdadm
>   */
> -#define MPB_ATTRIB_SUPPORTED		MPB_ATTRIB_CHECKSUM_VERIFY | \
> +#define MPB_ATTRIB_SUPPORTED	       (MPB_ATTRIB_CHECKSUM_VERIFY | \
>  					MPB_ATTRIB_2TB             | \
>  					MPB_ATTRIB_2TB_DISK        | \
>  					MPB_ATTRIB_RAID0           | \
>  					MPB_ATTRIB_RAID1           | \
>  					MPB_ATTRIB_RAID10          | \
>  					MPB_ATTRIB_RAID5           | \
> -					MPB_ATTRIB_EXP_STRIPE_SIZE
> +					MPB_ATTRIB_EXP_STRIPE_SIZE)
> +
> +/* Define attributes that are unused but not harmful */
> +#define MPB_ATTRIB_IGNORED		(MPB_ATTRIB_NEVER_USE)
> 
>  #define MPB_SECTOR_CNT 2210
>  #define IMSM_RESERVED_SECTORS 4096
> @@ -1141,11 +1144,14 @@ void examine_migr_rec_imsm(struct intel_super
> *super)
>  static int imsm_check_attributes(__u32 attributes)
>  {
>  	int ret_val = 1;
> -	__u32 not_supported = (MPB_ATTRIB_SUPPORTED)^0xffffffff;
> +	__u32 not_supported = MPB_ATTRIB_SUPPORTED^0xffffffff;
> +
> +	not_supported &= ~MPB_ATTRIB_IGNORED;
> 
>  	not_supported &= attributes;
>  	if (not_supported) {
> -		fprintf(stderr, Name "(IMSM): Unsupported attributes :
> %x\n", not_supported);
> +		fprintf(stderr, Name "(IMSM): Unsupported attributes :
> %x\n",
> +			(unsigned)__le32_to_cpu(not_supported));
>  		if (not_supported & MPB_ATTRIB_CHECKSUM_VERIFY) {
>  			dprintf("\t\tMPB_ATTRIB_CHECKSUM_VERIFY \n");
>  			not_supported ^= MPB_ATTRIB_CHECKSUM_VERIFY;
--
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