Re: Unable to mount multiple subvolumes of a single disk

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

Hi Sam,

  Thanks for verifying.

On 16/09/2014 01:13, Sam Thursfield wrote:
> Hi Anand
>
> On 15/09/14 17:09, Anand Jain wrote:
>>
>> Sam,
>>
>>   Thanks for reporting. Can you apply the following diff
>>   on top of 3.17rc5 and check if it helps.
>
> The patch fixes the issue, although it took a little tweaking to get it
> to apply cleanly.
>
>> -------
>> 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
>>
>>
>>
>> On 15/09/2014 23:54, Chris Mason wrote:
>>> On 09/15/2014 11:13 AM, Sam Thursfield wro:
>>>> Hi!
>>>>
>>>> I'm having an issue with the 3.17rc5 kernel which prevents having
>>>> multiple subvolumes of the same disk mounted.
>>>>
>>>> I'm not sure exactly the cause. I thought it might be because in my
>>>> system the root file system is itself a subvolume of the disk I'm
>>>> trying
>>>> to mount. But if I create a second disk image with two subvolumes, the
>>>> same thing occurs -- I can only mount one of them at a time.
>>>>
>>>> I've attached the output of a few commands, please let me know if you
>>>> want more info (I'm not subscribed to the list, please keep me in To:).
>>>>
>>>> We've bisected and found that the exact commit that changed the
>>>> behaviour is this one:
>>>> https://urldefense.proofpoint.com/v1/url?u=https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id%3Db96de000bc8bc9688b3a2abea4332bd57648a49f&k=ZVNjlDMF0FElm4dQtryO4A%3D%3D%0A&r=6%2FL0lzzDhu0Y1hL9xm%2BQyA%3D%3D%0A&m=qVtp3yxxUd8uElAkp118K4Bd0oZfeUOC%2BKUy3e6rRlA%3D%0A&s=0d2623956de100adc1185d2b75e9114384572b88c0330e74924baa1a2bce8d02
>>>>
>>>>
>>>>
>>>>
>>>> I'm afraid I'm not familiar with the Btrfs code base and so I don't
>>>> understand the exact meaning of the comments in that commit.
>>>
>>> Anand Jain is working on this in a separate thread.  I'll make sure the
>>> fix goes into the next rc, thanks for all the time spent bisecting.
>>>
>>> -chris
>>>
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>
>