Re: [MDADM PATCH 1/1] Array size is wrong when run mdadm -E

[Xiao Ni <xni@redhat.com>]

----- Original Message -----
> From: "Guoqing Jiang" <gqjiang@suse.com>
> To: "Xiao Ni" <xni@redhat.com>
> Cc: linux-raid@vger.kernel.org, ncroxon@redhat.com, "jes sorensen" <jes.sorensen@gmail.com>
> Sent: Wednesday, July 5, 2017 11:21:57 AM
> Subject: Re: [MDADM PATCH 1/1] Array size is wrong when run mdadm -E
> 
> 
> 
> On 07/05/2017 10:40 AM, Xiao Ni wrote:
> >
> > ----- Original Message -----
> >> From: "Guoqing Jiang" <gqjiang@suse.com>
> >> To: "Xiao Ni" <xni@redhat.com>
> >> Cc: linux-raid@vger.kernel.org, ncroxon@redhat.com, "jes sorensen"
> >> <jes.sorensen@gmail.com>
> >> Sent: Wednesday, July 5, 2017 9:56:35 AM
> >> Subject: Re: [MDADM PATCH 1/1] Array size is wrong when run mdadm -E
> >>
> >>
> >>
> >> On 07/04/2017 05:55 PM, Xiao Ni wrote:
> >>> ----- Original Message -----
> >>>> From: "Guoqing Jiang" <gqjiang@suse.com>
> >>>> To: "Xiao Ni" <xni@redhat.com>, linux-raid@vger.kernel.org
> >>>> Cc: ncroxon@redhat.com, "jes sorensen" <jes.sorensen@gmail.com>
> >>>> Sent: Tuesday, July 4, 2017 5:03:30 PM
> >>>> Subject: Re: [MDADM PATCH 1/1] Array size is wrong when run mdadm -E
> >>>>
> >>>>
> >>>>
> >>>> On 07/04/2017 02:50 PM, Xiao Ni wrote:
> >>>>> The size of array shows wrongly. It shifs wrong number.
> >>>>>
> >>>>> Signed-off-by: Xiao Ni <xni@redhat.com>
> >>>>> ---
> >>>>>     super1.c | 2 +-
> >>>>>     1 file changed, 1 insertion(+), 1 deletion(-)
> >>>>>
> >>>>> diff --git a/super1.c b/super1.c
> >>>>> index 86ec850..f3b864d 100644
> >>>>> --- a/super1.c
> >>>>> +++ b/super1.c
> >>>>> @@ -366,7 +366,7 @@ static void examine_super1(struct supertype *st,
> >>>>> char
> >>>>> *homehost)
> >>>>>     		}
> >>>>>     		if (ddsks) {
> >>>>>     			long long asize = __le64_to_cpu(sb->size);
> >>>>> -			asize = (asize << 9) * ddsks / ddsks_denom;
> >>>>> +			asize = (asize << 10) * ddsks / ddsks_denom;
> >>>>>     			printf("     Array Size : %llu%s\n",
> >>>>>     			       asize >> 10,  human_size(asize));
> >>>>>     		}
> >>>> IIRC, sb->size represents the num of sectors, so the shift should be 9.
> >>> Yes, it should be 9. It should pass bytes to human_size. Thanks for this.
> >>> It was introduced in d4633e06dfc01723911627fcb104af2ffb6f6a95. So there
> >>> is
> >>> the same problem in super0. Is it ok:
> >>>
> >>> diff --git a/super0.c b/super0.c
> >>> index 756cab5..4b4680c 100644
> >>> --- a/super0.c
> >>> +++ b/super0.c
> >>> @@ -131,9 +131,9 @@ static void examine_super0(struct supertype *st, char
> >>> *homehost)
> >>>                   }
> >>>                   if (ddsks) {
> >>>                           long long asize = sb->size;
> >>> -                       asize = (asize << 10) * ddsks / ddsks_denom;
> >>> +                       asize = (asize << 9) * ddsks / ddsks_denom;
> >>>                           printf("     Array Size : %llu%s\n",
> >>> -                              asize >> 10,  human_size(asize));
> >>> +                              asize >> 9,  human_size(asize));
> >>>                   }
> >> No, for 0.9 metadata, sb->size means KB not sector.
> >>
> > Thanks for this.
> >
> >>>           }
> >>>           printf("   Raid Devices : %d\n", sb->raid_disks);
> >>> diff --git a/super1.c b/super1.c
> >>> index 86ec850..2bb1454 100644
> >>> --- a/super1.c
> >>> +++ b/super1.c
> >>> @@ -368,7 +368,7 @@ static void examine_super1(struct supertype *st, char
> >>> *homehost)
> >>>                           long long asize = __le64_to_cpu(sb->size);
> >>>                           asize = (asize << 9) * ddsks / ddsks_denom;
> >>>                           printf("     Array Size : %llu%s\n",
> >>> -                              asize >> 10,  human_size(asize));
> >>> +                              asize >> 9,  human_size(asize));
> >>>                   }
> >>>                   if (sb->size != sb->data_size)
> >>>                           printf("  Used Dev Size : %llu%s\n",
> >> It is better that you can provide the output of "mdadm -E DISK" etc to
> >> prove
> >> current code is wrong, at least I can see correct output from my side.
> > [root@dell-per210-01 mdadm]# mdadm -E /dev/loop0
> > /dev/loop0:
> >            Magic : a92b4efc
> >          Version : 1.2
> >      Feature Map : 0x0
> >       Array UUID : 34f18365:ebf46416:ae1f365d:71cc579c
> >             Name : 0
> >    Creation Time : Tue Jul  4 02:09:03 2017
> >       Raid Level : raid5
> >     Raid Devices : 3
> >
> >   Avail Dev Size : 8261632 (3.94 GiB 4.23 GB)
> >       Array Size : 6291456 (6.00 GiB 6.44 GB)
> >    Used Dev Size : 6291456 (3.00 GiB 3.22 GB)
> >
> > Ah, I know it wants to show Array Size in KB. It's a raid5 with 3 loop
> > devices.
> > I thought they are all sectors subconsciously. But it's better to show
> > sizes with
> > the same unit. Right?
> 
> Perhaps that is why the human_size is used here.

But it's really too strange that Array Size is same with Used Dev Size. It's
easy to get confused. 

Regards
Xiao
> 
> Thanks,
> Guoqing
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