On Mon, Sep 27, 2010 at 02:50:17PM -0400, Valerie Aurora wrote: > On Sun, Sep 26, 2010 at 10:42:05PM -0700, Ram Pai wrote: > > On Mon, Sep 20, 2010 at 08:03:44PM -0400, Valerie Aurora wrote: > > > On Sun, Sep 19, 2010 at 10:25:53PM -0700, Ram Pai wrote: > > > > > > > > I understand your intentions, but I think you are making a wrong assumption. > > > > You seem to be thinking that if a slave-mount is cloned, the new cloned > > > > mount will also be a slave-mount and will hence receive propagations. As > > > > per shared subtree semantics, a slave-mount when cloned will create a private > > > > mount. Since your intention is to avoid generating any new mounts that > > > > recieve propagations, you should be checking for shared-mounts and > > > > slave-shared-mounts because these are the two kind of mounts that when > > > > cloned create new mounts that receive propagation. > > > > > > No. This isn't about the semantics of the clone mount operation. It > > > is about the administrator creating a slave mount, unioning it, and > > > then being surprised when the unioned file system does not receive > > > mount propagation events. > > > > > > Think of the source vfsmount tree as a set of command line arguments > > > for the union mount. > > > > Ok. In that case, you introduced a subtle change in the semantics of clone_mnt(). > > As I understand it, the flags parameter of clone_mnt() are meant to be a modifier > > for the cloned mount, not a filter on the source mount. > > Yes, that's it exactly. > > Do you have a suggestion for writing this a different way? We can > move it all into copy_tree() and leave clone_mnt() alone, at the cost > of a little code duplication and some acrobatics around possible > loopback support. I would probably lean towards a function tree_receives_propagation() similar to tree_contains_unbindable(), where you walk down the tree and check if there are any SLAVE or SHARED mounts. RP > > -VAL -- Ram Pai System X Device-Driver Enablement Lead Linux Technology Center Beaverton OR-97006 503-5783752 t/l 7753752 linuxram@xxxxxxxxxx -- 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
