Miklos, Sure, I think the approach of returning the lower layer's ino/dev combination for merged directories should be ok? I guess the one somewhat unexpected behavior/potential down side is st_dev spuriously being different within an overlayfs mount point, things like `find -xdev` or `du -x` won't recurse into directories on the upper layer. The advantage of the copying up the directory on getattr was it gave all the directories in the overlay unique inode numbers within a single device. Regards, Vito Caputo On Mon, Aug 15, 2016 at 2:08 AM, Miklos Szeredi <miklos@xxxxxxxxxx> wrote: > [This is *far* from being a trivial patch, please don't treat it as such] > > On Fri, Aug 12, 2016 at 03:34:51PM +0800, oc wrote: >> Since file inode points to the underlay from ovl_path_real method, the dir >> inode should also point to the one from underlay. This issue introduced >> problem when live migrates a container instance using criu, which need to >> convert inotify inode entry to file path, because inotify point to the real >> inode in underlay. > > Not quite sure what the problem is here. It is true that inotify is currently > broken. There's a fix pending for that here: > > https://git.kernel.org/cgit/linux/kernel/git/mszeredi/vfs.git/commit/?h=overlayfs-next&id=09557932babf3462125749212bc1cde574404fbb > > There's also an issue with inode numbers being unstable for directories: > > http://marc.info/?t=146914417200002&r=1&w=2 > > As explained in that thread the problem with always using the underlying > inode/dev is that it makes the inode number change when the directory is copied > up. > > So there are multiple, somewhat conflicting requirements here and it would be > good to have a solution that everyone is happy with and is unlikely to break > existing setups. > > Does the last patch in the above thread work for you? > > And what about if you additionally do > > -stat->dev = lowerstat.dev; > +stat->dev = dentry->d_sb->s_dev; > > ? > > Vito, could you also please supply feedback on those patches? > > Thanks, > Miklos -- To unsubscribe from this list: send the line "unsubscribe linux-unionfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
