On 05/22/2017 07:07 PM, NeilBrown wrote:
On Mon, May 22 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 | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/super1.c b/super1.c
index 2fcb814..03cea72 100644
--- a/super1.c
+++ b/super1.c
@@ -1267,8 +1267,10 @@ 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 >= max) {
+ sb->dev_roles[max] = __cpu_to_le16(MD_DISK_ROLE_SPARE);
Hi Neil,
Why do you assign to dev_roles[max]?
I meant to assure there will always be a spare spot in dev_roles[],
that is sb->max_dev at least is at lease 1 more than raid_disks.
Now I see what you mean in your reply to my last version patch.
max must equal i here, and a few lines later:
sb->dev_roles[i] = __cpu_to_le16(info->disk.raid_disk);
your assignment is over-written. So it is pointless.
If i was greater than max (which should be impossible), you assignment
here would corrupt the dev_roles table.
Please drop this assignment.
Yes, just increase the max_dev value is enough.
sb->max_dev = __cpu_to_le32(max+1);
+ }
random_uuid(sb->device_uuid);
@@ -1293,9 +1295,14 @@ static int update_super1(struct supertype *st, struct mdinfo *info,
}
}
} else if (strcmp(update, "linear-grow-update") == 0) {
+ unsigned int max = __le32_to_cpu(sb->max_dev);
sb->raid_disks = __cpu_to_le32(info->array.raid_disks);
sb->dev_roles[info->disk.number] =
__cpu_to_le16(info->disk.raid_disk);
+ if (info->array.raid_disks >= max) {
if raid_disks == max there is no need to change anything.
It is only when raid_disks > max that you need to increase max.
Yes, the max_dev should only be updated when raid_disks > max.
+ sb->dev_roles[max] = __cpu_to_le16(MD_DISK_ROLE_SPARE);
When you increase max, you do need to assign MD_DISK_ROLE_SPARE to the
new element, but you need to do that *before* disk.raid_disk is
assigned, in case info->disk.number == max (as it could be for the
recently added device).
I think it's also pointless to assign MD_DISK_ROLE_SPARE
since there is no SPARE in dev_roles when we need to update
sb->max_dev. The newly added device will not meet the condition
as max_dev has already been updated, that's saying, we only
need to update the max_dev value for original disks.
The following code should work
1297 } else if (strcmp(update, "linear-grow-update") == 0) {
1298 unsigned int max = __le32_to_cpu(sb->max_dev);
1299 sb->raid_disks = __cpu_to_le32(info->array.raid_disks);
1300 sb->dev_roles[info->disk.number] =
1301 __cpu_to_le16(info->disk.raid_disk);
1302 if (info->array.raid_disks > max) {
1303 sb->max_dev = __cpu_to_le32(max+1);
1304 }
Thank you for your patient review.
Lidong
NeilBrown
+ sb->max_dev = __cpu_to_le32(max+1);
+ }
} else if (strcmp(update, "resync") == 0) {
/* make sure resync happens */
sb->resync_offset = 0ULL;
--
2.12.0
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