On Wed, 18 Nov 2009, Daniel Drake wrote: > On Wed, 2009-11-18 at 12:50 +0100, Miklos Szeredi wrote: > > You can easily make a directory a root of a mount with > > > > mount --bind $DIR $DIR > > > > In your example, add this before 5. > > Thanks for the suggestion! And following on from that, we would do > "mount -o remount,ro /path/to/realroot" during shutdown > where /path/to/realroot is the bind mount that we created based on your > advice? I see some confusion here, there's no "path/to/realroot", the bind mount didn't actually do anything to the namespace, it just made "/versions/run/1" (which will later become "/") a mountpoint. At shutdown there's nothing special to do, other than "mount -o remount,ro /" > > Unfortunately, that approach doesn't solve the problem. If you remount a > bind-mount as read only then the "real" underlying mount is unaffected. > See the code flow in do_remount() : > > if (flags & MS_BIND) > err = change_mount_flags(path->mnt, flags); > else > err = do_remount_sb(sb, flags, data, 0); > Note: the "flags" tested here are supplied from the argument of mount(2), and are not flags stored in the mount. And btw, MS_BIND is not stored in the mount at all, there's absolutely no difference between a mount created with "--bind" and one without. So my suggestion should work fine. 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
