On Tue, 31 Aug 2010, Neil Brown wrote: > So: is this a problem? It may seem a bit confusing to someone who doesn't > understand what is happening, but we define that as not being a problem (to > avoid confusion: don't change U or L). > The important questions are: Can it cause corruption, and can it cause a > deadlock? No, I don't think this design will do that. So it might be enough just to document that online modification of upper or lower filesystems results in undefined behavior. But to prevent accidental damage, it's prudent (at least by default) to enforce the no-modification policy. Why do you think this feature of allowing modification is important? Lets take some typical use cases: - live cd: lower layer is hard r/o, upper layer makes no sense to modify online - thin client: lower layer is static except upgrades, which need special tools to support and is done offline, upper layer makes no sense to modify online Do you have some cases in mind where it makes at least a little sense to allow online modification of the underlying filesystems? Thanks, Miklos -- 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
