Al Viro <viro@xxxxxxxxxxxxxxxxxx>: > When the last reference to > mount past the umount_tree() (i.e. already with NULL ->mnt_ns) goes away, anything > subtree stuck to it will be detached from it and have its root unhashed and dropped. > In other words, such tree (e.g. result of umount -l) decays from root to leaves - > once all references to root are gone, it's cut off and all pieces are left > to decay. That is done with mount_writer (has to be - there are mount hash changes > and for those mount_writer is a hard requirement) and only after the final reference > to root has been dropped. I'm unable to understand this. As well as I understand your text, when you unmount some directory /a using "umount -l /a", then /a and all its children will stay as long as there are references to /a . This contradicts to reality. Consider this: # mount -t tmpfs tmpfs /a # mkdir /a/b # mount -t tmpfs tmpfs /a/b # mkdir /a/b/c # cd /a # umount -l /a According to your text, both /a and /a/b will stay, because we have reference to /a (via our cwd). But in reality /a/b disappears immidiately (i. e. "ls b" shows nothing, as opposed to "c"). This happens even if I test with your patches applied. So, your explanation seems to be wrong. -- Askar Safin
