Re: [RFC][PATCH] PM / Sleep: Freeze filesystems during systemsuspend/hibernation

From: Pavel Machek
Date: Wed Feb 01 2012 - 08:36:45 EST


> From: Rafael J. Wysocki <rjw@xxxxxxx>
> Freeze all filesystems during system suspend and (kernel-driven)
> hibernation by calling freeze_supers() for all superblocks and thaw
> them during the subsequent resume with the help of thaw_supers().
> This makes filesystems stay in a consistent state in case something
> goes wrong between system suspend (or hibernation) and the subsequent
> resume (e.g. journal replays won't be necessary in those cases). In


> particular, this should help to solve a long-standing issue that, in
> some cases, during resume from hibernation the boot loader causes the
> journal to be replied for the filesystem containing the kernel image
> and/or initrd causing it to become inconsistent with the information
> stored in the hibernation image.

Ungood. Why is bootloader/initrd doing that? If it mounts filesystem
read/write, what is the guarantee that it will not change data on the
filesystem, breaking stuff?

Bootloaders should just not replay journals.

> The user-space-driven hibernation (s2disk) is not covered by this
> change, because the freezing of filesystems prevents s2disk from
> accessing device special files it needs to do its job. bootloaders need to be fixed, anyway.
(cesky, pictures)
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