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 ? Thanks, Hu > > Thanks, > Kuai > > > > Thanks, > > Kuai > > > > . > > >
