On Thu, Jun 18, 2015 at 4:43 PM, Jan Olszak <j.olszak@xxxxxxxxxxx> wrote: > > > On 06/18/2015 03:39 PM, David Howells wrote: >> >> Jan Olszak <j.olszak@xxxxxxxxxxx> wrote: >> >>> I was wondering about a small improvement to overlayfs - optional, per >>> file >>> copy of write. >>> >>> 1. By default overlayfs would work as usual. >>> 2. If a file in 'lower' filesystem has an xattr set >>> (e.g. trusted.overlay.cow=n) the file would not be copied. >>> >>> What do you think? >> >> Ummm. What's the use case? How do you handle the file being part of >> multiple >> overlays? >> >> David >> > > I wan't to achieve 'files' granularity in overlayfs instead of 'directory' > granularity. > It would be useful in Linux containers configuration. Sometimes you don't > have the > power to change the images that are run inside containers and in one folder > you have both: > - files that have to be copied > - files that don't really need to be copied > > > trusted.overlay.cow==n indicates switching off copying the file to the upper > layer. > So with multiple overlays you would always have only one file from the > lower-most dir. What type filesystem is the lowest layer? Can you set immutable on it (chattr +i)? That would be the logical way to say "nobody can modify this file, not even root". Thanks, Miklos -- To unsubscribe from this list: send the line "unsubscribe linux-unionfs" in
