On Fri, Feb 26 2016, Shaohua Li wrote:
> check_reshape() is called from raid5d thread. raid5d thread shouldn't
> call mddev_suspend(), because mddev_suspend() waits for all IO finish
> but IO is handled in raid5d thread, we could easily deadlock here.
>
> Artur,
> It would be great if you can verify this works for your test.
>
> Reported-by: Artur Paszkiewicz <artur.paszkiewicz@xxxxxxxxx>
> Cc: NeilBrown <neilb@xxxxxxxx>
> Signed-off-by: Shaohua Li <shli@xxxxxx>
> ---
> drivers/md/raid5.c | 18 ++++++++++++++++++
> drivers/md/raid5.h | 2 ++
> 2 files changed, 20 insertions(+)
>
> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> index 7f770b0..c7fd070 100644
> --- a/drivers/md/raid5.c
> +++ b/drivers/md/raid5.c
> @@ -2089,6 +2089,14 @@ static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors)
> unsigned long cpu;
> int err = 0;
>
> + /*
> + * Never shrink. And mddev_suspend() could deadlock if this is called
> + * from raid5d. In that case, scribble_disks and scribble_sectors
> + * should equal to new_disks and new_sectors
> + */
> + if (conf->scribble_disks >= new_disks &&
> + conf->scribble_sectors >= new_sectors)
> + return 0;
> mddev_suspend(conf->mddev);
> get_online_cpus();
> for_each_present_cpu(cpu) {
> @@ -2110,6 +2118,10 @@ static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors)
> }
> put_online_cpus();
> mddev_resume(conf->mddev);
> + if (!err) {
> + conf->scribble_disks = new_disks;
> + conf->scribble_sectors = new_sectors;
> + }
> return err;
> }
>
> @@ -6413,6 +6425,12 @@ static int raid5_alloc_percpu(struct r5conf *conf)
> }
> put_online_cpus();
>
> + if (!err) {
> + conf->scribble_disks = max(conf->raid_disks,
> + conf->previous_raid_disks);
> + conf->scribble_sectors = max(conf->chunk_sectors,
> + conf->prev_chunk_sectors) / STRIPE_SECTORS;
Here we set ->scribble_sectors to a number of stripes rather than a
number of sectors. I think you need to remove the "/ STRIPE_SECTORS".
Otherwise:
Reviewed-by: NeilBrown <neilb@xxxxxxxx>
Thanks,
NeilBrown
> + }
> return err;
> }
>
> diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
> index a415e1c..ae6068d 100644
> --- a/drivers/md/raid5.h
> +++ b/drivers/md/raid5.h
> @@ -510,6 +510,8 @@ struct r5conf {
> * conversions
> */
> } __percpu *percpu;
> + int scribble_disks;
> + int scribble_sectors;
> #ifdef CONFIG_HOTPLUG_CPU
> struct notifier_block cpu_notify;
> #endif
> --
> 2.6.5
Attachment:
signature.asc
Description: PGP signature
