On Wed, Oct 04, 2017 at 06:05:23PM +1100, Dave Chinner wrote: > Basically, before thawing filesystems the rest of the kernel > infrastructure needs to have been restarted. i.e. the order > needs to be: > > freeze userspace > freeze filesystems > freeze kernel threads > freeze workqueues > > thaw workqueues > thaw kernel threads > thaw filesystems > thaw userspace > > and it should end up that way. > > > Or if we have a network block device, or > > something else in the storage stack that needs to run a kernel thread > > context (or a workqueue, etc.) --- is the fact that userspace is > > frozen mean the scheduler is going to refuse to schedule()? > > No. Well, that's what the answer *should* be. I was asking what this patch series does, and given that Luis reported that with this patch series ext4_commit_super(sb, 1) is hanging, I have my suspicions about what the answer might be with this patch set. (Especially since the claimed goal of the patch set is, "kthread freezing with filesystem freeze/thaw". Cheers, - Ted
