Jordi Pujol <jordipujolp@xxxxxxxxx> writes: > Hello, > > Next I expose some comments about the test of the overlayfs.v8 union > filesystem driver in the LneT live system, > > COMPILE THE KERNEL. > > some modifications are needed to compile: > > - rename fs/overlayfs/overlayfs.c to fs/overlayfs/module.c > > - modify fs/overlayfs/Makefile > # > # Makefile for the overlay filesystem. > # > > obj-$(CONFIG_OVERLAYFS_FS) += overlayfs.o > > overlayfs-objs := module.o \ > inode.o \ > dir.o \ > readdir.o \ > copy_up.o > > - add this line in fs/overlayfs/copy_up.c > #include <linux/security.h> > +#include <asm/uaccess.h> > #include "overlayfs.h" Thanks for reporting these. These are already fixed them in the latest version of the overlayfs.v8 tree. > Persistent mode: Works on a live system when the upperdir is on disk. > It's a good development, functionally easy and straight, seems very fast, > although I don't have measured how much, > > But some failure has been detected. > > DETECTED FAILURE. > > Scenario: > - lowerdir is an squashfs mounted on a tmpfs dir. > - upperdir is on an ext4 formatted partition. > > An script modifies a file that initially is in lowerdir, issuing consecutive > commands: > > sed -i -r -e 's|\[X-\*-Core\]|&\nServerTimeout=120|' /etc/kde4/kdm/kdmrc > sed -i -e 's/\(ServerArgsLocal\=.*\)$/\1 \-dpi 120/' /etc/kde4/kdm/kdmrc > sed -i -e 's/#\(ServerArgsRemote\=.*\)$/\1 \-dpi 120/' /etc/kde4/kdm/kdmrc > > Sometimes first or second changes are lost, only remain the changes > done by the last commands. Hmm, can you please send a minimal script and necessary files with which I can reproduce this? > IMPROVEMENTS and WHISHLIST. > > - upperdir on tmpfs, TODO feature already mentioned in the announcing message. > > - xattrs optionally disabled, implement mount option: "nouser_xattr" (option > name is taken from man mount). Actually this is the default (AFAIK the only) > behaviour for a Live system, Standard Linux Security is used in the root > filesystem, it's fast and a desktop system does not need complicated security > configurations. You can add nouser_xattr option for the upper filesystem and then things should work as expected. > - lowerdir may be a list of directories separated by colon (:), they must > appear in the options string from upper to lower. > That is very interesting, using this feature is easy to create different > configurations that use the same base Live OS. > example: > mount -t overlayfs upperdir=/upper,lowerdir=/lower1:/lower2:...:/lowerN > overlayfs /rootdir It shoulnd't be too difficult to implement multipe layers, but this is not a feature I want to implement before the current functinality is accepted and has had some time to mature. > - after the previous improvement has been done then we can think about > changing interactively a Live OS to another configuration, that is > done adding and removing branches to the union filesystem. Only some > Live systems make it, others do not have an interactive configuration > but require a reboot for changing to another configuration, Okay, see above comment. 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
