Re: [PATCH 1/2] btrfs-progs: fi show: Print missing device for a mounted file system

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

On 02/09/2021 22:28, Nikolay Borisov wrote:
> 
> 
> On 2.09.21 г. 14:44, Anand Jain wrote:
>> On 02/09/2021 18:06, Nikolay Borisov wrote:
>>> Currently when a device is missing for a mounted filesystem the output
>>> that is produced is unhelpful:
>>>
>>> Label: none  uuid: 139ef309-021f-4b98-a3a8-ce230a83b1e2
>>>      Total devices 2 FS bytes used 128.00KiB
>>>      devid    1 size 5.00GiB used 1.26GiB path /dev/loop0
>>>      *** Some devices missing
>>>
>>> While the context which prints this is perfectly capable of showing
>>> which device exactly is missing, like so:
>>>
>>> Label: none  uuid: 4a85a40b-9b79-4bde-8e52-c65a550a176b
>>>      Total devices 2 FS bytes used 128.00KiB
>>>      devid    1 size 5.00GiB used 1.26GiB path /dev/loop0
>>>      devid    2 size 0 used 0 path /dev/loop1 ***MISSING***


This change has to percolate to xfstests as well. I think btrfs/197,
btrfs/198 and btrfs/003 depends on the existing format. IMO those
test cases still have to be backward btrfs-progs compatible.

Thanks, Anand


>>>
>>> This is a lot more usable output as it presents the user with the id
>>> of the missing device and its path.
>>
>> Looks better. How does this fair in the case of unmounted btrfs? Because
>> btrfs fi show is supposed to work on an unmounted btrfs to help find
>> btrfs devices.
> 
> On unmounted fs the output is unchanged - i.e we simply print "missing
> device" because there is no way to derive the name of the missing
> device. Check print_one_uuid for reference.
> 
> <snip>
>