Re: [Lsf-pc] [LSF/MM/BPF TOPIC] Filesystem Suspend Resume

James Bottomley
2025-03-27T14:28:37Z

On Wed, 2025-03-26 at 11:25 -0400, James Bottomley wrote:
> On Wed, 2025-03-26 at 15:59 +0100, Jan Kara wrote:
> [...]
> > So to summarize I think we may need to introduce freezable variant
> > of
> > percpu_rwsem_down_read() and use it in sb_start_write().
>
> Aye, aye, sir! and thanks for making the can of worms bigger ...
>
> This is what I came up with for freezable variants of the
> sb_write_start().  I'm still building the kernel (laptop only ...) so
> I'll let you know in an hour or so if it actually works.

Slightly longer than an hour, but I can confirm this all works. I've
also tested it with filesystem on loop on filesystem (with ext4 as
upper and lower) and it hibernates just fine running some fio stress.

I've posted what I'm currently working with here:

https://lore.kernel.org/all/20250327140613.25178-1-James.Bottomley@HansenPartnership.com/

So people can see what I'm currently playing with.

Regards,

James