On 07/10/2012 10:52 AM, Arnd Hannemann wrote: > Hi, > > Am 10.07.2012 05:30, schrieb Christian Robert: >> I agree with you, but you should never mount a snapshot of a btrfs filesystem at the same time the original is, >> because both the original and the snapshot had same "device fsid 5c3e8ca2-da56-4ade-9fef-103a6a8a70c2" I think that the kernel should be smarter in this regard. At kernel level, as golden rule it should be not possible to add a duplicate fsid if the previous one is mounted. "btrfs dev scan" MUST return an error in this case. This in any case is an error. Today it seems that if a device with the same fsid is already registered, the new one overwrites the old one (or almost the name is overwritten). This could be acceptable if the filesystem is unmounted. I think that it is a serious error otherwise. >> >> the kernel will tkink twice and fold back to the same device. > > If that is correct the bug is that the kernel lets me mount the same device fsid on different devices twice. > >> >> btrsf does not behave like other filesystems, you can't snapshot a btrfs filesystem >> and hope to mount the snapshot somewhere else. > >> snapsoot also duplicate lots of things internally that have no sence in a snapshot (like raid level, single or multiple devies ...) > > I see. However, I expect a "simple" btrfs to just work or fail gracefully. > > Best regards, > Arnd > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > . > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
