On Tue, Oct 31 2017, Tomasz Majchrzak wrote:
> On Tue, Oct 17, 2017 at 04:18:36PM +1100, NeilBrown wrote:
>> The ->recovery_offset shows how much of a non-InSync device is actually
>> in sync - how much has been recoveryed.
>>
>> When performing a recovery, ->curr_resync and ->curr_resync_completed
>> follow the device address being recovered and so can be used to update
>> ->recovery_offset.
>>
>> When performing a reshape, ->curr_resync* might follow the device
>> addresses (raid5) or might follow array addresses (raid10), so cannot
>> in general be used to set ->recovery_offset. When reshaping backwards,
>> ->curre_resync* measures from the *end* of the array-or-device, so is
>> particularly unhelpful.
>>
>> So change the common code in md.c to only use ->curr_resync_complete
>> for the simple recovery case, and add code to raid5.c to update
>> ->recovery_offset during a forwards reshape.
>>
>> Signed-off-by: NeilBrown <neilb@xxxxxxxx>
>> ---
>> drivers/md/md.c | 32 +++++++++++++++++++++-----------
>> drivers/md/raid5.c | 18 ++++++++++++++++++
>> 2 files changed, 39 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/md/md.c b/drivers/md/md.c
>> index a9f1352b3849..d1dfc9879368 100644
>> --- a/drivers/md/md.c
>> +++ b/drivers/md/md.c
>> @@ -2453,10 +2453,17 @@ void md_update_sb(struct mddev *mddev, int force_change)
>> }
>> }
>>
>> - /* First make sure individual recovery_offsets are correct */
>> + /* First make sure individual recovery_offsets are correct
>> + * curr_resync_completed can only be used during recovery.
>> + * During reshape/resync it might use array-addresses rather
>> + * that device addresses.
>> + */
>> rdev_for_each(rdev, mddev) {
>> if (rdev->raid_disk >= 0 &&
>> mddev->delta_disks >= 0 &&
>> + test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) &&
>> + test_bit(MD_RECOVERY_RECOVER, &mddev->recovery) &&
>> + !test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
>> !test_bit(Journal, &rdev->flags) &&
>> !test_bit(In_sync, &rdev->flags) &&
>> mddev->curr_resync_completed > rdev->recovery_offset)
>> @@ -8507,16 +8514,19 @@ void md_do_sync(struct md_thread *thread)
>> } else {
>> if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery))
>> mddev->curr_resync = MaxSector;
>> - rcu_read_lock();
>> - rdev_for_each_rcu(rdev, mddev)
>> - if (rdev->raid_disk >= 0 &&
>> - mddev->delta_disks >= 0 &&
>> - !test_bit(Journal, &rdev->flags) &&
>> - !test_bit(Faulty, &rdev->flags) &&
>> - !test_bit(In_sync, &rdev->flags) &&
>> - rdev->recovery_offset < mddev->curr_resync)
>> - rdev->recovery_offset = mddev->curr_resync;
>> - rcu_read_unlock();
>> + if (!test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
>> + test_bit(MD_RECOVERY_RECOVER, &mddev->recovery)) {
>> + rcu_read_lock();
>> + rdev_for_each_rcu(rdev, mddev)
>> + if (rdev->raid_disk >= 0 &&
>> + mddev->delta_disks >= 0 &&
>> + !test_bit(Journal, &rdev->flags) &&
>> + !test_bit(Faulty, &rdev->flags) &&
>> + !test_bit(In_sync, &rdev->flags) &&
>> + rdev->recovery_offset < mddev->curr_resync)
>> + rdev->recovery_offset = mddev->curr_resync;
>> + rcu_read_unlock();
>> + }
>> }
>> }
>> skip:
>> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
>> index a8df52130f8a..89ad79614309 100644
>> --- a/drivers/md/raid5.c
>> +++ b/drivers/md/raid5.c
>> @@ -5739,6 +5739,7 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *sk
>> */
>> struct r5conf *conf = mddev->private;
>> struct stripe_head *sh;
>> + struct md_rdev *rdev;
>> sector_t first_sector, last_sector;
>> int raid_disks = conf->previous_raid_disks;
>> int data_disks = raid_disks - conf->max_degraded;
>> @@ -5861,6 +5862,15 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *sk
>> return 0;
>> mddev->reshape_position = conf->reshape_progress;
>> mddev->curr_resync_completed = sector_nr;
>> + if (!mddev->reshape_backwards)
>> + /* Can update recovery_offset */
>> + rdev_for_each(rdev, mddev)
>> + if (rdev->raid_disk >= 0 &&
>> + !test_bit(Journal, &rdev->flags) &&
>> + !test_bit(In_sync, &rdev->flags) &&
>> + rdev->recovery_offset < sector_nr)
>> + rdev->recovery_offset = sector_nr;
>> +
>> conf->reshape_checkpoint = jiffies;
>> set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
>> md_wakeup_thread(mddev->thread);
>> @@ -5959,6 +5969,14 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *sk
>> goto ret;
>> mddev->reshape_position = conf->reshape_progress;
>> mddev->curr_resync_completed = sector_nr;
>> + if (!mddev->reshape_backwards)
>> + /* Can update recovery_offset */
>> + rdev_for_each(rdev, mddev)
>> + if (rdev->raid_disk >= 0 &&
>> + !test_bit(Journal, &rdev->flags) &&
>> + !test_bit(In_sync, &rdev->flags) &&
>> + rdev->recovery_offset < sector_nr)
>> + rdev->recovery_offset = sector_nr;
>> conf->reshape_checkpoint = jiffies;
>> set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
>> md_wakeup_thread(mddev->thread);
>>
>>
>> --
>
> Hi,
>
> This patch has caused a regression in following IMSM RAID scenario:
That's unfortunate.
>
> mdadm --create /dev/md/imsm0 --metadata=imsm --raid-devices=4 /dev/nvme[0-3]n1 --run
> mdadm --create /dev/md/r10 --level=10 --size=100M --raid-devices=4 /dev/nvme[0-3]n1 --run --assume-clean
>
> MDADM_EXPERIMENTAL=1 mdadm --grow /dev/md/r10 --level=0
> MDADM_EXPERIMENTAL=1 mdadm --grow /dev/md/imsm0 --raid-devices=4
>
> cat /proc/mdstat
> Personalities : [raid10] [raid0] [raid6] [raid5] [raid4]
> md126 : active raid4 nvme0n1[3] nvme2n1[2] nvme1n1[1]
> 409600 blocks super external:/md127/0 level 4, 128k chunk, algorithm 0 [5/3] [UU_U_]
>
> md127 : inactive nvme3n1[3](S) nvme2n1[2](S) nvme1n1[1](S) nvme0n1[0](S)
> 4420 blocks super external:imsm
Why isn't nvme3n1 in md126? Did it not get added, or did it get removed
for some reason?
If it wasn't added, raid5_start_reshape() would have failed, so I guess
it must have been removed??
>
> The array should have been reshaped to 4-disk RAID0 but it has failed in
> the middle of reshape as RAID4.
>
> Following condition is not true for above scenario:
>
>> + if (!test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
>> + test_bit(MD_RECOVERY_RECOVER, &mddev->recovery)) {
No, it isn't meant to be. This code doesn't work reliably in the
reshape case. When reshaping raid5 (or raid4), reshape_request updates
rdev->recovery_offset. ... maybe end_reshape needs to update it too.
If you add this patch, does it help?
Thanks,
NeilBrown
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 89ad79614309..a99ae1be9175 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -7964,6 +7964,7 @@ static void end_reshape(struct r5conf *conf)
{
if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
+ struct md_rdev *rdev;
spin_lock_irq(&conf->device_lock);
conf->previous_raid_disks = conf->raid_disks;
@@ -7971,6 +7972,12 @@ static void end_reshape(struct r5conf *conf)
smp_wmb();
conf->reshape_progress = MaxSector;
conf->mddev->reshape_position = MaxSector;
+ rdev_for_each(rdev, conf->mddev)
+ if (rdev->raid_disk >= 0 &&
+ !test_bit(Journal, &rdev->flags) &&
+ !test_bit(In_sync, &rdev->flags))
+ rdev->recovery_offset = MaxSector;
+
spin_unlock_irq(&conf->device_lock);
wake_up(&conf->wait_for_overlap);
Attachment:
signature.asc
Description: PGP signature
