Re: Unable to mount multiple subvolumes of a single disk

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

Hi Chris,


>> -------
>> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
>> index e9676a4..1224b61 100644
>> --- a/fs/btrfs/volumes.c
>> +++ b/fs/btrfs/volumes.c
>> @@ -533,7 +533,7 @@ static noinline int device_list_add(const char *path,
>>                   * the btrfs dev scan cli, after FS has been mounted.
>>                   */
>>                  if (fs_devices->opened) {
>> -                       return -EBUSY;
>> +                       goto out;
>>                  } else {
>>                          /*
>>                           * That is if the FS is _not_ mounted and if you
>> @@ -566,6 +566,7 @@ static noinline int device_list_add(const char *path,
>>          if (!fs_devices->opened)
>>                  device->generation = found_transid;
>>
>> +out:
>>          *fs_devices_ret = fs_devices;
>>
>>          return ret;
>
> Anand, are you planning on sending a full patch out for this?  One concern
> I have is that after the device_list_add call:
>
>
>      if (!ret && fs_devices_ret)
>              (*fs_devices_ret)->total_devices = total_devices;
>
> We should only be doing this from the newest super, not blindly overwriting.
> But that's a merge window fix.  For now I just want to deal with the regression,
> and your patch above looks good.
>
> Thanks for jumping on this one.


  Sorry for the trouble.
  yes, I will be sending a full patch. I am finding too difficult
  to revive the function btrfs_scan_one_device() which is predominately
  to handle device scan and list_update _before_ any mount. Further
  to the concern which you mention above, there is Ioctl
  BTRFS_IOC_DEV_READY also using this function, which absolutely should
  not have any intention to update the device list, but it does ..
  theoretically. And I note that this ioctl is used by systemd as well.
  So the fix is getting a bit complicated. I am attempting.

Thanks, Anand

> -chris
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