Re: [PATCH 0/8][RFC] IO latency/throughput fixes

From: Linus Torvalds
Date: Tue Apr 07 2009 - 10:40:27 EST




On Tue, 7 Apr 2009, Mark Lord wrote:
>
> What happens with ext3 "writeback", and ext4 "whatever",
> when one does the quickie reboot method:
>
> ALT-SYSRQ-S ALT-SYSRQ-U ALT-SYSRQ-S ALT-SYSRQ-B
>
> ???

Since 's' syncs (I think 'u' does too, as part of making things
read-only), the data blocks will be on disk after the boot regardless of
any other ordering.

Of course, it will leave all your lock-files files alone, and I can almost
guarantee that some daemons (read: "NetworkManager") will then fail on the
next boot because they think they are already running.

Linus
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