Re: [PATCH v2 6/6] super: add filesystem freezing helpers for suspend and hibernate

[Christian Brauner]

On Mon, Mar 31, 2025 at 12:23:04PM +0200, Jan Kara wrote:
> On Sat 29-03-25 09:42:19, Christian Brauner wrote:
> > Allow the power subsystem to support filesystem freeze for
> > suspend and hibernate.
> > 
> > Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
> 
> One comment below. Otherwise feel free to add:
> 
> Reviewed-by: Jan Kara <jack@xxxxxxx>
> 
> > +void filesystems_thaw(bool hibernate)
> > +{
> > +	__iterate_supers(filesystems_thaw_callback, NULL,
> > +			 SUPER_ITER_UNLOCKED | SUPER_ITER_REVERSE);
> > +}
> 
> I think we should thaw in normal superblock order, not in reverse one? To
> thaw the bottommost filesystem first? The filesystem thaw callback can
> write to the underlying device and this could cause deadlocks...

Yep, I've fixed that already up in vfs-6.16.super yesterday.
Sorry, forgot to mention that here. Thanks for noticing!