Hello Miklos, Miklos Szeredi: > +The lower filesystem can be any filesystem supported by Linux and does > +not need to be writable. The lower filesystem can even be another > +overlayfs. ... When user mounts overlayfs over and over like this, # mount -t overlayfs -o upper=/rw1,lower=/ro1 none /ovl1 # mount -t overlayfs -o upper=/rw2,lower=/ovl1 none /ovl2 ::: # mount -t overlayfs -o upper=/rwN,lower=/ovl{N-1} none /ovlN And if he modify a file in the bottom RO layer, then overlayfs copies-up the file into each RW layer? - 'fileA' exists in only /ro1. - nested mounts. - run "echo append >> /ovlN/fileA" - is fileA copied-up to /rw1, and then to /rw2, and then ... to /rwN? If user specify a single dir as every upper laery, then the copyup will be done only once, or such RW layers are not allowed? J. R. Okajima -- 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