Re: [PATCH 2/2] btrfs-progs: doc: add extra note on flipping read-only on received subvolumes

[Qu Wenruo <wqu@suse.com>]

On 2021/9/10 下午2:33, Nikolay Borisov wrote:
> 
> 
> On 10.09.21 г. 9:03, Qu Wenruo wrote:
>> Signed-off-by: Qu Wenruo <wqu@suse.com>
>> ---
>>   Documentation/btrfs-property.asciidoc | 6 ++++++
>>   1 file changed, 6 insertions(+)
>>
>> diff --git a/Documentation/btrfs-property.asciidoc b/Documentation/btrfs-property.asciidoc
>> index 4796083378e4..8949ea22edae 100644
>> --- a/Documentation/btrfs-property.asciidoc
>> +++ b/Documentation/btrfs-property.asciidoc
>> @@ -42,6 +42,12 @@ the following:
>>   
>>   ro::::
>>   read-only flag of subvolume: true or false
>> ++
>> +NOTE: For recevied subvolumes, flipping from read-only to read-write will
>> +either remove the recevied UUID and prevent future incremental receive
>> +(on newer kernels), or cause future data corruption and recevie failure
>> +(on older kernels).
> 
> Hang on a minute, flipping RO->RW won't cause corruption by itself.

It looks like the "future" part is not clear enough.

> So
> flipping will just break incremental sends which is completely fine.

The "breaking" part is more straightforward for newer kernel, but not 
older kernels (it's definitely breaking, but not that directly observable)

Thanks,
Qu

> 
>> +
>>   label::::
>>   label of the filesystem. For an unmounted filesystem, provide a path to a block
>>   device as object. For a mounted filesystem, specify a mount point.
>>
>