On Thu, 18 Aug 2011, Milan Broz wrote: > On 08/18/2011 05:49 PM, Lukas Czerner wrote: > > On Thu, 18 Aug 2011, Jeff Moyer wrote: > >> Seems you missed the bizarre case of configuring a loop device over top > >> of a block device. > > > > Wow, that is a bizarre case I did not think about at all. But since it > > is so bizarre, do we even care ? The thing is that the only case where > > it would make a difference is if the loop device is put on top of block > > device which actually supports discard. > > > > In order to fix that I would need to dig out the actual limits for that > > device and set that appropriately for the loop device. Is that worth it > > ? It is not like someone will ever do that (or should) :). > > It is bizarre (and being device-mapper developer I surely know better way :-) > but people are still using that. > > Historically one of the use of underlying block device was cryptoloop, but here > I think it should be completely deprecated (cryptsetup can handle all old loop > modes as well and default modes for cryptoloop are not safe). > [Can we finally remove crypto loop option it from kernel? ... ok, just tried:)] > > There is also out of tree loop-aes based on heavily patched loop device > which usually uses block device underneath > (cryptsetup already can handle all loop-aes modes as well). > > Sometimes it is used with --offset parameter for some reason > (like linear device-mapper mapping). > > So I do not care if you do not support discard here but please do not break > support for block device mapped through loop. I do not think that this is the case with my patch. Also, as you know using discard on encrypted device is not a good idea. Thanks! -Lukas > > Thanks, > Milan > -- -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
