Re: [PATCH v7 1/2] btrfs: Introduce "rescue=" mount option

[Anand Jain <anand.jain@oracle.com>]

On 5/6/20 7:36 pm, David Sterba wrote:
> On Fri, Jun 05, 2020 at 06:04:01PM +0800, Anand Jain wrote:
>> On 4/6/20 3:18 pm, Qu Wenruo wrote:
>>> This patch introduces a new "rescue=" mount option group for all those
>>> mount options for data recovery.
>>>
>>> Different rescue sub options are seperated by ':'. E.g
>>> "ro,rescue=nologreplay:usebackuproot".
>>> (The original plan is to use ';', but ';' needs to be escaped/quoted,
>>> or it will be interpreted by bash)
>>
>>    I fell ':' isn't suitable here.
> 
> What do you suggest then?
> 

There isn't any other choice, right? Probably that's the reason for
-o device it is -o device=dev1,device=dev2 still remains separated?
IMO if there isn't a choice it is ok to leave them separate.

But as I commented in the other thread instead of
-o rescue=skipbg:another1:another2 why not just -o rescue
and mount thread shall skip the checks that fail and mount the
fs in RO if possible. The dmesg -k must show the checks that
were failed and had to skip to make the RO mount successful.
So, that becomes clear about the errors which lead to the current RO 
mount, instead of going through the logs to figure out. This is a more 
user-friendly approach as there is one rescue option. But I am not
sure if it is possible?

Thanks, Anand


>>> And obviously, user can specify rescue options one by one like:
>>> "ro,rescue=nologreplay,rescue=usebackuproot"
>>
>>    This should suffice right?
> 
> Setting the rescue= value separately should be supported, but requiring
> to write the option name for each value defeats the purpose to make it
> compact and user friendly.
>