On Tue, 5 Jun 2012 18:28:13 neil wrote:
>On Tue, 5 Jun 2012 15:32:56 +0800 majianpeng <majianpeng@xxxxxxxxx> wrote:
>
>> In Commit 7bfec5f35c68121e7b1849f3f4166dd96c8da5b3:
>> "if there is a spare and a want_replacement device, start replacement."
>> But it did not consider the raid was degraded at the same time.
>> When we add spare disk in order to recovery, unless raid was ok and then
>> started replacement or vice versa.
>>
>> Signed-off-by: majianpeng <majianpeng@xxxxxxxxx>
>> ---
>> drivers/md/raid5.c | 48 +++++++++++++++++++++++++++++-------------------
>> 1 files changed, 29 insertions(+), 19 deletions(-)
>>
>> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
>> index d267672..f74c9a5 100644
>> --- a/drivers/md/raid5.c
>> +++ b/drivers/md/raid5.c
>
>Good point, but the code feels a little ... clumsy.
>
>How about this?
>
>NeilBrown
>
>
>diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
>index d267672..4f0861e 100644
>--- a/drivers/md/raid5.c
>+++ b/drivers/md/raid5.c
>@@ -5465,10 +5465,9 @@ static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
> if (rdev->saved_raid_disk >= 0 &&
> rdev->saved_raid_disk >= first &&
> conf->disks[rdev->saved_raid_disk].rdev == NULL)
>- disk = rdev->saved_raid_disk;
>- else
>- disk = first;
>- for ( ; disk <= last ; disk++) {
>+ first = rdev->saved_raid_disk;
>+
>+ for (disk = first; disk <= last; disk++) {
> p = conf->disks + disk;
> if (p->rdev == NULL) {
> clear_bit(In_sync, &rdev->flags);
>@@ -5477,8 +5476,10 @@ static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
> if (rdev->saved_raid_disk != disk)
> conf->fullsync = 1;
> rcu_assign_pointer(p->rdev, rdev);
>- break;
>+ goto out;
> }
>+ }
>+ for (disk = first; disk <= last; disk++) {
> if (test_bit(WantReplacement, &p->rdev->flags) &&
> p->replacement == NULL) {
> clear_bit(In_sync, &rdev->flags);
>@@ -5490,6 +5491,7 @@ static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
> break;
> }
> }
>+out:
> print_raid5_conf(conf);
> return err;
> }
>
>
I tested and found a bug.I corrected it like this.
But I had a question:why p->rdev not protect by rcu_read_lock?
I think it should be.
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index d267672..24162c1 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -5465,10 +5465,9 @@ static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
if (rdev->saved_raid_disk >= 0 &&
rdev->saved_raid_disk >= first &&
conf->disks[rdev->saved_raid_disk].rdev == NULL)
- disk = rdev->saved_raid_disk;
- else
- disk = first;
- for ( ; disk <= last ; disk++) {
+ first = rdev->saved_raid_disk;
+
+ for (disk = first; disk <= last; disk++) {
p = conf->disks + disk;
if (p->rdev == NULL) {
clear_bit(In_sync, &rdev->flags);
@@ -5477,10 +5476,15 @@ static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
if (rdev->saved_raid_disk != disk)
conf->fullsync = 1;
rcu_assign_pointer(p->rdev, rdev);
- break;
+ goto out;
}
- if (test_bit(WantReplacement, &p->rdev->flags) &&
- p->replacement == NULL) {
+ }
+
+ for (disk = first; disk <= last; disk++) {
+ p = conf->disks + disk;
+ if (p->rdev != NULL &&
+ test_bit(WantReplacement, &p->rdev->flags) &&
+ p->replacement == NULL) {
clear_bit(In_sync, &rdev->flags);
set_bit(Replacement, &rdev->flags);
rdev->raid_disk = disk;
@@ -5490,6 +5494,7 @@ static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
break;
}
}
+out:
print_raid5_conf(conf);
return err;
}
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