Re: [PATCH 2/2] btrfs: add support for SUPER_FLAG_CHANGING_FSID in btrfs.ko

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

>> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
>> index a69e5944dc08..8b76faa77235 100644
>> --- a/fs/btrfs/disk-io.c
>> +++ b/fs/btrfs/disk-io.c
>> @@ -61,7 +61,8 @@
>>   				 BTRFS_HEADER_FLAG_RELOC |\
>>   				 BTRFS_SUPER_FLAG_ERROR |\
>>   				 BTRFS_SUPER_FLAG_SEEDING |\
>> -				 BTRFS_SUPER_FLAG_METADUMP)
>> +				 BTRFS_SUPER_FLAG_METADUMP |\
>> +				 BTRFS_SUPER_FLAG_CHANGING_FSID)
> 
> If we don't want the half changed fs to be mounted, it's better not to
> include FLAG_CHANGING_FSID into BTRFS_SUPER_FLAG_SUPP.

   Anyway BTRFS_SUPER_FLAG_SUPP as such does not stop to mount, it
  just warns. So when there is a new flag which is not supported
  we get this warning. As in the case with BTRFS_SUPER_FLAG_METADUMP_V2.
  As in 1/2 BTRFS_SUPER_FLAG_METADUMP_V2 in kernel is defined but not
  supported. However since we are supporting
  BTRFS_SUPER_FLAG_CHANGING_FSID, so adding to BTRFS_SUPER_FLAG_SUPP make
  sense to me. ?

Thanks, Anand