On Wed, Mar 02, 2022 at 12:17:30PM -0800, Hugh Dickins wrote: > Please ignore this patch for now: I presume Xavier did not understand > the "from akpm to Linus in next merge window" flow, and thought he had > to resend the patch to you. I will resend a fixed v4 version in a moment, sorry for the noise (and I indeed did not fully understand the flow). > > And finally - if we really want to treat btime as a first-class entity > > and expect things like tmpfs to support it, then we should just bite > > the bullet and put it in 'struct inode' along with the other times. > I've no objection if someone does that later. I might give it a try if this is something that can be of interest. The idea of having btime in 'struct inode' would make the btime a first-class citizen, allowing to have more consistent (w.r.t filesystem types) behavior. This would also mean allowing to _change_ it, typically to allow archivers to set the creation time as they do for {a,c,m}time. Currently, birth time semantic is bound to the current filesystem's life cycle and as such is irrelevant after a restore, or a 'tar xf'. The only gray area to me is whether or not we "can" always change this property without unforeseen consequences, typically for ext4.