Hi,
在 2023/07/29 14:16, Xueshi Hu 写道:
On Sat, Jul 29, 2023 at 11:51:27AM +0800, Yu Kuai wrote:
Hi,
在 2023/07/29 11:36, Yu Kuai 写道:
Hi,
在 2023/07/29 11:29, Xueshi Hu 写道:
I think this is wrong, you should at least keep following:
set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
md_wakeup_thread(mddev->thread);
I fail to comprehend the rationale behind the kernel's need to invoke
raid1d() repeatedly despite the absence of any modifications.
It appears that raid1d() is responsible for invoking
md_check_recovery()
and resubmit the failed io.
No, the point here is to set MD_RECOVERY_NEEDED and MD_RECOVERY_RECOVER,
so that md_check_recovery() can start to reshape.
I apologize, but I am still unable to comprehend your idea.
If mmdev->delta_disks == 0 , what is the purpose of invoking
md_check_recovery() again?
Sounds like you think raid1_reshape() can only be called from
md_check_recovery(), please take a look at other callers.
Thank you for the quick reply and patience.
Of course, I have checked all the caller of md_personality::check_reshape.
- layout_store
- action_store
- chunk_size_store
- md_ioctl
__md_set_array_info
update_array_info
- md_check_recovery
- md_ioctl
__md_set_array_info
update_array_info
update_raid_disks
- process_metadata_update
md_reload_sb
check_sb_changes
update_raid_disks
- raid_disks_store
update_raid_disks
There are three categories of callers except md_check_recovery().
1. write to sysfs
2. ioctl
3. revice instructions from md cluster peer
Using "echo 4 > /sys/devices/virtual/block/md10/md/raid_disks" as an
example, if the mddev::raid_disks is already 4, I don't think
raid1_reshape() should set MD_RECOVERY_RECOVER and MD_RECOVERY_NEEDED
bit, then wake up the mddev::thread to call md_check_recovery().
Is there any counterexample to demonstrate the issues that may arise if
md_check_recovery() is not called out of raid1_reshape() ?
And even if raid1_reshape() is called from md_check_recovery(),
which means reshape is interupted, then MD_RECOVERY_RECOVER
and MD_RECOVERY_RECOVER need to be set, so that reshape can
continue.
raid1 only register md_personality::check_reshape, all the work related
with reshape are handle in md_personality::check_reshape.
What's the meaning of "reshape can continue" ? In another word, what's
the additional work need to do if mddev::raid_disks doesn't change ?
Okay, I missed that raid1 doesn't have 'start_reshape', reshape here
really means recovery, synchronize data to new disks. Never mind what
I said "reshape can continue", it's not possible for raid1.
Then the problem is the same from 'recovery' point of view:
if the 'recovery' is interrupted, before this patch, even if raid_disks
is the same, raid1_reshape() will still set the flag and then
md_check_recovery() will try to continue the recovery. I'd like to
keep this behaviour untill it can be sure that no user will be
affected.
Thanks,
Kuai
Thanks,
Hu
Thanks,
Kuai
Thanks,
Kuai
.
.
