APPLIED: [SRU][Bionic][PATCH 0/1] Fix md raid deadlock during resync

[Kleber Souza]

On 7/16/19 12:57 AM, Connor Kuehl wrote:
> [Impact]
> 
> * If regular and resync IO happen at the same time during a regular IO
>   split, the split bio will wait until resync IO finishes while at the
>   same time the resync IO is waiting for regular IO to finish. This
>   results in deadlock.
> 
> * I believe this only impacts Bionic as Disco+ already contains this
>   commit. Xenial doesn't contain the commit that this one fixes.
> 
> [Test Case]
> 
> The test kernel containing this commit received positive feedback in the
> launchpad bug.
> 
> From the launchpad bug comment #10:
> 
> "For reproduce on 4.15.0-50-generic: Make new raid-10, add some io fio/dd, 
> unpack anaconda archives, after minute or two deadlocked"
> 
> [Regression Potential]
> 
> * This fix has been in mainline since December 2018 and I don't see any
>   fixup commits upstream referencing this one. The small number of
>   changes in this commit seem reasonable for managing the `nr_pending`
>   adjustments which preclude either regular or resync IO.
> 
> Guoqing Jiang (1):
>   md: fix raid10 hang issue caused by barrier
> 
>  drivers/md/raid10.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 

This patch was already applied to bionic/master-next branch.

Thanks,
Kleber