On Tue, May 16 2017, Lidong Zhong wrote:
> The value of sb->max_dev will always be increased by 1 when adding
> a new disk in linear array. It causes an inconsistence between each
> disk in the array and the "Array State" value of "mdadm --examine DISK"
> is wrong. For example, when adding the first new disk into linear array
> it will be:
>
> Array State : RAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
> ('A' == active, '.' == missing, 'R' == replacing)
>
> Adding the second disk into linear array it will be
>
> Array State : .AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
> ('A' == active, '.' == missing, 'R' == replacing)
>
> Signed-off-by: Lidong Zhong <lzhong@xxxxxxxx>
> ---
> super1.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/super1.c b/super1.c
> index 87a74cb..3d49bee 100644
> --- a/super1.c
> +++ b/super1.c
> @@ -1184,8 +1184,10 @@ static int update_super1(struct supertype *st, struct mdinfo *info,
> break;
> sb->dev_number = __cpu_to_le32(i);
> info->disk.number = i;
> - if (max >= __le32_to_cpu(sb->max_dev))
> + if (i >= __le32_to_cpu(sb->max_dev)) {
This change is correct - thanks. Though
if (i >= max) {
might be clearer and simpler.
> sb->max_dev = __cpu_to_le32(max+1);
> + sb->dev_roles[sb->max_dev] = __cpu_to_le16(MD_DISK_ROLE_SPARE);
This change is wrong.
At the very least, the dev_roles[] array needs to be indexed by a
host-order number, not a little-endian number.
But the change is not needed because dev_roles[max_dev] is never used.
See role_from_sb().
dev_rols[max_dev - 1] does need to be set, but the line
sb->dev_roles[i] = __cpu_to_le16(info->disk.raid_disk);
almost certainly does that.
It might be better to do
if (i >= max) {
while (max <= i) {
sb->dev_roles[max] = __cpu_to_le16(MD_DISK_ROLE_SPARE);
max += 1;
}
sb->max_dev = __cpu_to_le32(max);
}
> + }
>
> random_uuid(sb->device_uuid);
>
> @@ -1214,6 +1216,10 @@ static int update_super1(struct supertype *st, struct mdinfo *info,
> sb->raid_disks = __cpu_to_le32(info->array.raid_disks);
> sb->dev_roles[info->disk.number] =
> __cpu_to_le16(info->disk.raid_disk);
> + if (sb->raid_disks+1 >= __le32_to_cpu(sb->max_dev)) {
> + sb->max_dev = __cpu_to_le32(sb->raid_disks+1);
> + sb->dev_roles[sb->max_dev] = __cpu_to_le16(MD_DISK_ROLE_SPARE);
Again, max_dev is little-endian, so cannot be used as an index.
And I think you are updating the wrong element in the dev_roles array.
Thanks,
NeilBrown
> + }
> } else if (strcmp(update, "resync") == 0) {
> /* make sure resync happens */
> sb->resync_offset = 0ULL;
> --
> 2.12.0
Attachment:
signature.asc
Description: PGP signature
