Re: [PATCH V3 08/13] md: set MD_CHANGE_PENDING in a spinlocked region

[Shaohua Li <shli@kernel.org>]

On Tue, Apr 26, 2016 at 09:56:26PM -0400, Guoqing Jiang wrote:
> Some code waits for a metadata update by:
> 
> 1. flagging that it is needed (MD_CHANGE_DEVS or MD_CHANGE_CLEAN)
> 2. setting MD_CHANGE_PENDING and waking the management thread
> 3. waiting for MD_CHANGE_PENDING to be cleared
> 
> If the first two are done without locking, the code in md_update_sb()
> which checks if it needs to repeat might test if an update is needed
> before step 1, then clear MD_CHANGE_PENDING after step 2, resulting
> in the wait returning early.
> 
> So make sure all places that set MD_CHANGE_PENDING are protected by
> mddev->lock.
> 
> Reviewed-by: NeilBrown <neilb@suse.com>
> Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
> ---
> V3 changes:
> 1. use spin_lock_irqsave/spin_unlock_irqrestore in error funcs and
>    raid10's __make_request

shouldn't other places use spin_lock_irq/spin_unlock_irq? interrupt can occur
after you do spin_lock(), and if it's md_error, we deadlock.

please resend the whole series.

Thanks,
Shaohua