Re: [PATCH][v2] btrfs: introduce rescue=onlyfs

Graham Cobb
2020-07-21T16:05:59Z

On 21/07/2020 16:10, Josef Bacik wrote:
> One of the things that came up consistently in talking with Fedora about
> switching to btrfs as default is that btrfs is particularly vulnerable
> to metadata corruption. If any of the core global roots are corrupted,
> the fs is unmountable and fsck can't usually do anything for you without
> some special options.
>
> Qu addressed this sort of with rescue=skipbg, but that's poorly named as
> what it really does is just allow you to operate without an extent root.
> However there are a lot of other roots, and I'd rather not have to do
>
> mount -o rescue=skipbg,rescue=nocsum,rescue=nofreespacetree,rescue=blah
>
> Instead take his original idea and modify it so it just works for
> everything. Turn it into rescue=onlyfs, and then any major root we fail
> to read just gets left empty and we carry on.

Am I the only one who dislikes the name? "onlyfs" does not seem at all
meaningful to me, as a system manager - the people it is apparently
aimed at. I really don't understand what it is supposed to mean and it
sounds like some developer debugging option or something.

If it means "only filesystem" that doesn't make sense to me - the whole
thing is the filesystem. I guess "only data" might be more meaningful
but if the aim is to turn on as much recovery as possible to help the
user to save their data then why not just say so?

Something like "rescue=max", "rescue=recoverymode", "rescue=dataonly",
"rescue=ignoreallerrors" or "rescue=emergency" might be more meaningful.