Re: Loud "pop" coming from hard drive on reboot

From: Tejun Heo
Date: Wed Apr 18 2007 - 09:06:49 EST


Alan Cox wrote:
Thought about that and querying power state before doing shutdown sequence but things get somewhat ugly because shutdown sequence is driven from sd->shutdown(). We'll have to snoop both sync and shutdown commands and check whether the system is shutting down. Also, I felt very uneasy about faking successful completion to SYNCHRONIZE_CACHE.

If you see a synchronize cache succeed and you then see the drive
shutdown succeed then you know that a sync cache can be faked as ok
safely. Any other command in between or after and it doesn't get faked

This seems pretty easy to deal with at command issue.

Yeah, right. I guess I'm too anal about SYNCHRONIZE_CACHE.

I dunno. It's already too late for 2.6.21. I was hoping we could get distros to update shutdown utilities in not-too-distant future but I have no experience with that. Is that just a wishful thinking?

Probably not, but it will take a year or so and throughout this time
period everyone with the wrong combination of shutdown and kernel (which
will be a lot of people who compile their own kernels) are going to have
problems caused by what is a very obscure piece of libata internal
behaviour they'll never even know about.

Okay, will do another round of the patch.

Thanks.

--
tejun
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