On Tue, 2008-01-08 at 12:35 +0100, Miklos Szeredi wrote: > @@ -510,10 +533,16 @@ static struct vfsmount *clone_mnt(struct > int flag) > { > struct super_block *sb = old->mnt_sb; > - struct vfsmount *mnt = alloc_vfsmnt(old->mnt_devname); > + struct vfsmount *mnt; > > + if (flag & CL_SETUSER) { > + int err = reserve_user_mount(); > + if (err) > + return ERR_PTR(err); > + } > + mnt = alloc_vfsmnt(old->mnt_devname); > if (!mnt) > - return ERR_PTR(-ENOMEM); > + goto alloc_failed; > > mnt->mnt_flags = old->mnt_flags; > atomic_inc(&sb->s_active); I think there's a little race here. We could have several users racing to get to this point when nr_user_mounts==max_user_mounts-1. One user wins the race and gets their mount reserved. The others get the error out of reserve_user_mount(), and return. But, the winner goes on to error out on some condition further down in clone_mnt() and never actually instantiates the mount. Do you think this is a problem? I think just about the one solution is to block new mounters on a sleepable lock until the race winner actually finishes their mount operation. -- Dave - 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