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-rw-r--r--fs/pnode.c63
1 files changed, 62 insertions, 1 deletions
diff --git a/fs/pnode.c b/fs/pnode.c
index fbaca7df2eb0..53d411a371ce 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);
@@ -162,6 +167,19 @@ 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) {
@@ -505,6 +523,15 @@ 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.
@@ -517,11 +544,23 @@ 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,
@@ -529,6 +568,27 @@ 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)) {
@@ -542,6 +602,7 @@ 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;