Re: [RFC PATCH] xfs: use log_incompat feature instead of speculate matching

Gao Xiang
2020-08-24T09:58:21Z

On Mon, Aug 24, 2020 at 04:19:00PM +0800, Gao Xiang wrote:
> From: Gao Xiang <hsiangkao@redhat.com>
>
> Use a log_incompat feature just to be safe.
> If the current mount is in RO state, it will defer
> to next RW remount.
>
> Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
> ---
>
> After some careful thinking, I think it's probably not working for
> supported V4 XFS filesystem. So, I think we'd probably insist on the
> previous way (correct me if I'm wrong)...
>
> (since xfs_sb_to_disk() refuses to set up any feature bits for non V5
> fses. That is another awkward setting here (doesn't write out/check
> feature bits for V4 even though using V4 sb reserved fields) and
> unless let V4 completely RO since this commit. )
>
> Just send out as a RFC patch. Not fully tested after I thought as above.

Unless we also use sb_features2 for V4 filesystem to entirely
refuse to mount such V4 filesystem...
Some more opinions on this?

Thanks,
Gao Xiang