On 11/29/2016 12:51 AM, Jes Sorensen wrote:
> Artur Paszkiewicz <artur.paszkiewicz@xxxxxxxxx> writes:
>> Enable creating and assembling IMSM raid5 arrays with PPL.
>>
>> Write the IMSM MPB location for a device to the newly added rdev
>> sb_start sysfs attribute and 'journal_ppl' to 'state' attribute for
>> every active member.
>>
>> Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@xxxxxxxxx>
>> ---
>> mdadm.h | 1 +
>> super-intel.c | 33 +++++++++++++++++++++++++++++++++
>> sysfs.c | 4 ++++
>> 3 files changed, 38 insertions(+)
>>
>> diff --git a/mdadm.h b/mdadm.h
>> index 4eabf59..5600341 100755
>> --- a/mdadm.h
>> +++ b/mdadm.h
>> @@ -252,6 +252,7 @@ struct mdinfo {
>> unsigned long long custom_array_size; /* size for non-default sized
>> * arrays (in sectors)
>> */
>> + unsigned long long sb_start;
>> #define NO_RESHAPE 0
>> #define VOLUME_RESHAPE 1
>> #define CONTAINER_RESHAPE 2
>> diff --git a/super-intel.c b/super-intel.c
>> index df09272..79a3d78 100644
>> --- a/super-intel.c
>> +++ b/super-intel.c
>> @@ -1261,6 +1261,15 @@ static void print_imsm_dev(struct intel_super *super,
>> }
>> printf("\n");
>> printf(" Dirty State : %s\n", dev->vol.dirty ? "dirty" : "clean");
>> + printf(" RWH Policy : ");
>> + if (dev->rwh_policy == RWH_OFF)
>> + printf("off\n");
>> + else if (dev->rwh_policy == RWH_DISTRIBUTED)
>> + printf("PPL distributed\n");
>> + else if (dev->rwh_policy == RWH_JOURNALING_DRIVE)
>> + printf("PPL journaling drive\n");
>> + else
>> + printf("<unknown:%d>\n", dev->rwh_policy);
>> }
>>
>> static void print_imsm_disk(struct imsm_disk *disk, int index, __u32 reserved)
>> @@ -3043,6 +3052,15 @@ static void getinfo_super_imsm_volume(struct supertype *st, struct mdinfo *info,
>> }
>> }
>> }
>> +
>> + if (info->array.level == 5) {
>> + if (dev->rwh_policy == RWH_OFF)
>> + info->rwh_policy = RWH_POLICY_OFF;
>> + else if (dev->rwh_policy == RWH_DISTRIBUTED)
>> + info->rwh_policy = RWH_POLICY_PPL;
>> + else
>> + info->rwh_policy = RWH_POLICY_UNKNOWN;
>> + }
>> }
>>
>> static __u8 imsm_check_degraded(struct intel_super *super, struct imsm_dev *dev,
>> @@ -3177,6 +3195,9 @@ static void getinfo_super_imsm(struct supertype *st, struct mdinfo *info, char *
>>
>> disk = &super->disks->disk;
>> info->data_offset = total_blocks(&super->disks->disk) - reserved;
>> + /* mpb anchor sector - see store_imsm_mpb() */
>> + info->sb_start = total_blocks(&super->disks->disk) -
>> + ((2 * super->sector_size) >> 9);
>> info->component_size = reserved;
>> info->disk.state = is_configured(disk) ? (1 << MD_DISK_ACTIVE) : 0;
>> /* we don't change info->disk.raid_disk here because
>
> Hi Artur,
>
> I have been sitting staring at the above for a while, and looking at
> store_imsm_mpb() it is not clear to me what is meant to happen here.
>
> For 4k sector drives, aren't you pushing back sb_start way further than
> you are for 512 byte sector drives? Ie. you are subtracting 16 sectors
> for the 4k drive but only two sectors for the 512 byte sector drive?
>
> Maybe it's because it's Monday or I lost the last of my marbles, but
> could you possibly enlighten me here please?
Jes,
You read it correctly. The reason for this is that the IMSM anchor is
located in the second _logical_ sector from the end of the drive. So for
4k drives this will be 16 512-byte sectors from the end.
Thanks,
Artur
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