Re: [PATCH v9 1/1] nvmet: support reservation feature

[Guixin Liu <kanie@linux.alibaba.com>]

在 2024/9/24 16:24, Dmitry Bogdanov 写道:
>> I take a look again, if we set self new holder before call
>> nvmet_pr_unreg_all_others_by_prkey(), the
>> nvmet_pr_unreg_all_others_by_prkey() will
>>
>> not unregister self, so this will not goto nvmet_pr_unregister_one()'s
>> calling nvmet_pr_resv_released().
> Yes, and this is a reason not to try to fix non-atomicity (anothter my
> comment) by setting new holder before unregistering.
>
> Regarding this place, here nvmet_pr_resv_released should be called for
> original_rtype !=*_REG_ONLY with a note that _REG_ONLY handled in nvmet_pr_unregister_one.
>
> Please, do not take my suggestions "how to fix" as a direct order, it's
> just suggestion.
>
I'm a little confused, if we dont set new holder before unregistering,

how do we fix the non-atomicity problem?

My opinion is that setting current host to holder first can not only

make sure that during unregistering other host can not access, but also

ensure that nvmet_pr_unregister_one will not unregiter the new holder(In 
nvmet_pr_unreg_all_others_by_prkey, I exclude current host),

so that we dont need to worry about doule call nvmet_pr_resv_released.