On 7.01.20 г. 3:31 ч., Su Yue wrote:
> On 2020/1/6 11:12 PM, Nikolay Borisov wrote:
>>
>>
>> On 12.12.19 г. 13:01 ч., damenly.su@xxxxxxxxx wrote:
>>> From: Su Yue <Damenly_Su@xxxxxxx>
>>>
>>> Since a scanned device may be the device pulled into disk without
>>> metadata_uuid feature, there may already be changing devices there.
>>> Here copy fsid and metadata_uuid for above case.
>>>
>>> Signed-off-by: Su Yue <Damenly_Su@xxxxxxx>
>>
>>
>> What does this patch fix, why is it needed? It seems to be independent
>> of the split brain fixes?
>>
>
> Sorry for the messy and short commit log.
> It's one of the split brain fixes.
>
> As mails I replied you earlier, the case
> is for device which succeed to sync in
> the second transaction and is without
> metadata_uuid feature. If there is fs_devices
> already scanned, the device's fsid instead of
> metadata_uuid(NULL here) should be copied into
> the fs_devices->metada_uuid field.
I figures as much as I started tackling the problem. So this must be
part of the patch which fixes aforementioned split brain scenario. I
have already developed some patches + tests. So will be sending those,
since they are very similar to what you posted originally I will retain
your SOB line.
>
> Thanks.
>
>>> ---
>>> fs/btrfs/volumes.c | 11 +++++++----
>>> 1 file changed, 7 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
>>> index faf9cdd14f33..b21ab45e76a0 100644
>>> --- a/fs/btrfs/volumes.c
>>> +++ b/fs/btrfs/volumes.c
>>> @@ -964,13 +964,16 @@ static noinline struct btrfs_device
>>> *device_list_add(const char *path,
>>> * metadata_uuid/fsid values of the fs_devices.
>>> */
>>> if (*new_device_added && fs_devices_found &&
>>> - has_metadata_uuid && fs_devices->fsid_change &&
>>> + fs_devices->fsid_change &&
>>> found_transid > fs_devices->latest_generation) {
>>> memcpy(fs_devices->fsid, disk_super->fsid,
>>> BTRFS_FSID_SIZE);
>>> - memcpy(fs_devices->metadata_uuid,
>>> - disk_super->metadata_uuid, BTRFS_FSID_SIZE);
>>> -
>>> + if (has_metadata_uuid)
>>> + memcpy(fs_devices->metadata_uuid,
>>> + disk_super->metadata_uuid, BTRFS_FSID_SIZE);
>>> + else
>>> + memcpy(fs_devices->metadata_uuid,
>>> + disk_super->fsid, BTRFS_FSID_SIZE);
>>> fs_devices->fsid_change = false;
>>> }
>>>
>>>
>
