Re: [PATCH] md: wake raid456 reshape waiters before suspend

[Yu Kuai]

在 2026/3/27 22:07, Yu Kuai 写道:

> During raid456 reshape, direct IO across the reshape position can sleep
> in raid5_make_request() waiting for reshape progress while still
> holding an active_io reference. If userspace then freezes reshape and
> writes md/suspend_lo or md/suspend_hi, mddev_suspend() kills active_io
> and waits for all in-flight IO to drain.
>
> This can deadlock: the IO needs reshape progress to continue, but the
> reshape thread is already frozen, so the active_io reference is never
> dropped and suspend never completes.
>
> raid5_prepare_suspend() already wakes wait_for_reshape for dm-raid. Do
> the same for normal md suspend when reshape is already interrupted, so
> waiting raid456 IO can abort, drop its reference, and let suspend
> finish.
>
> The mdadm test tests/25raid456-reshape-deadlock reproduces the hang.
>
> Fixes: 714d20150ed8 ("md: add new helpers to suspend/resume array")
> Signed-off-by: Yu Kuai<yukuai@xxxxxxxxx>
> ---
>   drivers/md/md.c | 11 +++++++++++
>   1 file changed, 11 insertions(+)
Applied to md-7.1

-- 
Thansk,
Kuai