Re: [[Patch mdadm] 1/5] Make the IMSM_DEVNAME_AS_SERIAL option work when creating containers. This allows a person to testing using loopback devices that don't support serial number queries.

[Doug Ledford <dledford@redhat.com>]

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On 01/18/2010 11:42 PM, Dan Williams wrote:
> On Mon, Jan 18, 2010 at 6:55 PM, Doug Ledford <dledford@redhat.com> wrote:
>> On 01/18/2010 05:13 PM, Dan Williams wrote:
>>> Hi Doug,
>>>
>>> On Mon, Jan 11, 2010 at 1:38 PM, Doug Ledford <dledford@redhat.com> wrote:
>>>> Signed-off-by: Doug Ledford <dledford@redhat.com>
>>>> ---
>>>>  super-intel.c |    5 ++++-
>>>>  1 files changed, 4 insertions(+), 1 deletions(-)
>>>>
>>>> diff --git a/super-intel.c b/super-intel.c
>>>> index d6951cc..fcf438c 100644
>>>> --- a/super-intel.c
>>>> +++ b/super-intel.c
>>>> @@ -3208,7 +3208,10 @@ static int add_to_super_imsm(struct supertype *st, mdu_disk_info_t *dk,
>>>>        dd->fd = fd;
>>>>        dd->e = NULL;
>>>>        rv = imsm_read_serial(fd, devname, dd->serial);
>>>> -       if (rv) {
>>>> +       if (rv && check_env("IMSM_DEVNAME_AS_SERIAL")) {
>>>> +               memset(dd->serial, 0, MAX_RAID_SERIAL_LEN);
>>>> +               fd2devname(fd, (char *) dd->serial);
>>>> +       } else if (rv) {
>>>
>>> This just duplicates the check already inside imsm_read_serial().
>>> Containers on loopback devices worked before this patch, so I'll send
>>> a revert.
>>>
>>> --
>>> Dan
>>
>> Me thinks you didn't try it, because this does not duplicate the code in
>> imsm_read_serial().  That code is needed to assemble an IMSM array that
>> already exists on loopback devices.  This is needed to *create* an imsm
>> container on fresh loopback devices.  I'm assuming your imsm container
>> superblocks already existed or some such.
>>
> 
> Me thinks you did not try it either :-)
> 
> # export IMSM_DEVNAME_AS_SERIAL=1
> # mdadm --zero-superblock /dev/loop[0-3]
> # mdadm -Eb /dev/loop[0-4]
> # mdadm -E /dev/loop0
> mdadm: No md superblock detected on /dev/loop0.
> # mdadm --create /dev/md/imsm /dev/loop[0-3] -n 4 -e imsm
> mdadm: /dev/loop0 appears to contain an ext2fs file system
>     size=306816K  mtime=Sat Nov 21 10:54:51 2009
> mdadm: /dev/loop1 appears to contain an ext2fs file system
>     size=306816K  mtime=Sat Nov 21 10:54:51 2009
> mdadm: imsm unable to enumerate platform support
>     array may not be compatible with hardware/firmware
> Continue creating array? y
> mdadm: container /dev/md/imsm prepared.
> # mdadm -Eb /dev/loop[0-3]
> ARRAY metadata=imsm
>    spares=4
> 
> # mdadm -E /dev/loop0
> /dev/loop0:
>           Magic : Intel Raid ISM Cfg Sig.
>         Version : 1.0.00
>     Orig Family : 00000000
>          Family : 697a43ec
>      Generation : 00000001
>            UUID : ffffffff:ffffffff:ffffffff:ffffffff
>        Checksum : c3d8d367 correct
>     MPB Sectors : 1
>           Disks : 1
>    RAID Devices : 0
> 
>   Disk00 Serial : /dev/loop0
>           State : spare
>              Id : 00000000
>     Usable Size : 204382 (99.81 MiB 104.64 MB)
> 
> This is with:
> commit 6acad4811b06335a2602fa1eeaec3a8f47f96591
> Author: Michael Evan <mjevans1983@gmail.com>
> Date:   Wed Dec 9 21:52:18 2009 -0800
> 
> --
> Dan

Ah, OK.  I did say we had been carrying this around in our SRPM for a
while, I just hadn't tried removing it since it was necessary.  I take
it you are implying that that changeset is the one that rendered it no
longer necessary?

-- 
Doug Ledford <dledford@redhat.com>
              GPG KeyID: CFBFF194
	      http://people.redhat.com/dledford

Infiniband specific RPMs available at
	      http://people.redhat.com/dledford/Infiniband


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