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

Josef Bacik
2020-07-21T17:40:50Z

On 7/21/20 1:34 PM, Graham Cobb wrote:
> On 21/07/2020 18:16, David Sterba wrote:
>> On Tue, Jul 21, 2020 at 04:56:55PM +0100, Graham Cobb wrote:
>>> 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.
>>
>> From user perspective the option should have a high level semantics,
>> like you suggest above. We should add individual options to try to work
>> around specific damage if not just for testing purposes, having more
>> flexibility is a good thing.
>
> I would also prefer not to have checksum checking disabled by this "try
> harder" option. I would imagine turning on "ignore whatever checks you
> can to get me my data back mode", retrieving all the readable data with
> valid checksums and getting errors for things which cannot be verified.
> Then I would make a decision as to whether to enable another option to
> even provide files which the filesystem cannot guarantee have not been
> corrupted because it can't check checksums. Even if that is all the
> files (because the checksum tree is destroyed) I should have to make an
> explicit acknowledgement that I want that.
>

If somebody wants to add finer grained stuff later I'm fine with that, right now
I'm addressing the case where a lot of things are dead. Thanks,

Josef