diff --git a/fs/pnode.c b/fs/pnode.c index acc2eefbc4ff..d15c63e97ef1 100644 --- a/fs/pnode.c +++ b/fs/pnode.c @@ -24,6 +24,11 @@ static inline struct mount *first_slave(struct mount *p) return list_entry(p->mnt_slave_list.next, struct mount, mnt_slave); } +static inline struct mount *last_slave(struct mount *p) +{ + return list_entry(p->mnt_slave_list.prev, struct mount, mnt_slave); +} + static inline struct mount *next_slave(struct mount *p) { return list_entry(p->mnt_slave.next, struct mount, mnt_slave); @@ -164,6 +169,19 @@ static struct mount *propagation_next(struct mount *m, } } +static struct mount *skip_propagation_subtree(struct mount *m, + struct mount *origin) +{ + /* + * Advance m such that propagation_next will not return + * the slaves of m. + */ + if (!IS_MNT_NEW(m) && !list_empty(&m->mnt_slave_list)) + m = last_slave(m); + + return m; +} + static struct mount *next_group(struct mount *m, struct mount *origin) { while (1) { @@ -507,6 +525,15 @@ static void restore_mounts(struct list_head *to_restore) } } +static void cleanup_umount_visitations(struct list_head *visited) +{ + while (!list_empty(visited)) { + struct mount *mnt = + list_first_entry(visited, struct mount, mnt_umounting); + list_del_init(&mnt->mnt_umounting); + } +} + /* * collect all mounts that receive propagation from the mount in @list, * and return these additional mounts in the same list. @@ -519,11 +546,23 @@ int propagate_umount(struct list_head *list) struct mount *mnt; LIST_HEAD(to_restore); LIST_HEAD(to_umount); + LIST_HEAD(visited); - list_for_each_entry(mnt, list, mnt_list) { + /* Find candidates for unmounting */ + list_for_each_entry_reverse(mnt, list, mnt_list) { struct mount *parent = mnt->mnt_parent; struct mount *m; + /* + * If this mount has already been visited it is known that it's + * entire peer group and all of their slaves in the propagation + * tree for the mountpoint has already been visited and there is + * no need to visit them again. + */ + if (!list_empty(&mnt->mnt_umounting)) + continue; + + list_add_tail(&mnt->mnt_umounting, &visited); for (m = propagation_next(parent, parent); m; m = propagation_next(m, parent)) { struct mount *child = __lookup_mnt(&m->mnt, @@ -531,6 +570,27 @@ int propagate_umount(struct list_head *list) if (!child) continue; + if (!list_empty(&child->mnt_umounting)) { + /* + * If the child has already been visited it is + * know that it's entire peer group and all of + * their slaves in the propgation tree for the + * mountpoint has already been visited and there + * is no need to visit this subtree again. + */ + m = skip_propagation_subtree(m, parent); + continue; + } else if (child->mnt.mnt_flags & MNT_UMOUNT) { + /* + * We have come accross an partially unmounted + * mount in list that has not been visited yet. + * Remember it has been visited and continue + * about our merry way. + */ + list_add_tail(&child->mnt_umounting, &visited); + continue; + } + /* Check the child and parents while progress is made */ while (__propagate_umount(child, &to_umount, &to_restore)) { @@ -544,6 +604,7 @@ int propagate_umount(struct list_head *list) umount_list(&to_umount, &to_restore); restore_mounts(&to_restore); + cleanup_umount_visitations(&visited); list_splice_tail(&to_umount, list); return 0;