On 05/19/2017 12:36 PM, NeilBrown wrote:
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.
Hi Neil,
The reason I set all the dev_roles[0~max_dev-1] is because
the following code
552 printf(" Array State : ");
553 for (d = 0; d < __le32_to_cpu(sb->raid_disks) + delta_extra;
d++) {
554 int cnt = 0;
555 unsigned int i;
556 for (i = 0; i < __le32_to_cpu(sb->max_dev); i++) {
557 unsigned int role = __le16_to_cpu(sb->dev_roles[i]);
558 if (role == d)
559 cnt++;
560 }
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);
}
Thanks for the advice.
+ }
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.
Yes, I didn't realized the valude is conversed to little-endian and the
index is wrong too. Thank you for pointing this out. I will submit
another version patch.
Thanks,
Lidong
Thanks,
NeilBrown
+ }
} else if (strcmp(update, "resync") == 0) {
/* make sure resync happens */
sb->resync_offset = 0ULL;
--
2.12.0
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