[pve-devel] [PATCH v2 storage] rbd: alloc image: fix #3970 avoid ambiguous rbd path

[Thomas Lamprecht]

On 08.04.22 10:04, Fabian Grünbichler wrote:
> On April 6, 2022 1:46 pm, Aaron Lauterer wrote:
>> If two RBD storages use the same pool, but connect to different
>> clusters, we cannot say to which cluster the mapped RBD image belongs to
>> if krbd is used. To avoid potential data loss, we need to verify that no
>> other storage is configured that could have a volume mapped under the
>> same path before we create the image.
>>
>> The ambiguous mapping is in
>> /dev/rbd/<pool>/<ns>/<image> where the namespace <ns> is optional.
>>
>> Once we can tell the clusters apart in the mapping, we can remove these
>> checks again.
>>
>> See bug #3969 for more information on the root cause.
>>
>> Signed-off-by: Aaron Lauterer <a.lauterer at proxmox.com>
> 
> Acked-by: Fabian Grünbichler <f.gruenbichler at proxmox.com>
> Reviewed-by: Fabian Grünbichler <f.gruenbichler at proxmox.com>
> 
> (small nit below, and given the rather heavy-handed approach a 2nd ack 
> might not hurt.. IMHO, a few easily fixable false-positives beat more 
> users actually running into this with move disk/volume and losing 
> data..)

The obvious question to me is: why bother with this workaround when we can
make udev create the symlink now already?

Patching the rules file and/or binary shipped by ceph-common, or shipping our
own such script + rule, would seem relatively simple.