> The reason why I implemented that way, is to less confuse the user and > provide more flexibility. With my implementation, we have the ability > to share any part of the tree, without bothering if it is a mountpoint > or not. The side effect of this operation is, it ends up creating > a vfsmount if the dentry is not a mountpoint. > > so when a user says > mount --make-shared /tmp/abc > the tree under /tmp/abc becomes shared. > With your suggestion either the user will get -EINVAL or the tree > under / will become shared. The second behavior will be really > confusing.
You are right. > I am ok with -EINVAL. I think it should be this then. These operations are similar to a remount (they don't actually mount something, just change some property of a mount). Remount returns -EINVAL if not performed on the root of a mount. > Also there is another reason why I used this behavior. Lets say /mnt > is a mountpoint and Say a user does > mount make-shared /mnt > > and then does > mount --bind /mnt/abc /mnt1 > > NOTE: we need propogation to be set up between /mnt/abc and /mnt1 and > propogation can only be set up for vfsmounts. In this case /mnt/abc > is not a mountpoint. I have two choices, either return -EINVAL > or create a vfsmount at that point. But -EINVAL is not consistent > with standard --bind behavior. So I chose the later behavior. > > Now that we anyway need this behavior while doing bind mounts from > shared trees, I kept the same behavior for --make-shared. Well, the mount program can easily implement this behavior if wanted, just by doing the 'bind dir dir' and then doing 'make-shared dir'. The other way round (disabling the automatic 'bind dir dir') is much more difficult. > > Some notes (maybe outside the code) explaining the mechanism of the > > propagations would be nice. Without these it's hard to understand the > > design decisions behind such an implementation. > > Ok. I will make a small writeup on the mechanism. That will help, thanks. Miklos - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
