2 files changed, 28 insertions, 3 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index 010d5bebcb7e..1894d1878dbc 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1099,6 +1099,13 @@ static void mntput_no_expire(struct mount *mnt)
         rcu_read_unlock();
 
         list_del(&mnt->mnt_instance);
+
+        if (unlikely(!list_empty(&mnt->mnt_mounts))) {
+                struct mount *p, *tmp;
+                list_for_each_entry_safe(p, tmp, &mnt->mnt_mounts,  mnt_child) {
+                        umount_mnt(p);
+                }
+        }
         unlock_mount_hash();
 
         if (likely(!(mnt->mnt.mnt_flags & MNT_INTERNAL))) {
@@ -1370,6 +1377,7 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how)
                 propagate_umount(&tmp_list);
 
         while (!list_empty(&tmp_list)) {
+                bool disconnect;
                 p = list_first_entry(&tmp_list, struct mount, mnt_list);
                 list_del_init(&p->mnt_expire);
                 list_del_init(&p->mnt_list);
@@ -1378,10 +1386,18 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how)
                 if (how & UMOUNT_SYNC)
                         p->mnt.mnt_flags |= MNT_SYNC_UMOUNT;
 
-                pin_insert_group(&p->mnt_umount, &p->mnt_parent->mnt, &unmounted);
+                disconnect = !IS_MNT_LOCKED_AND_LAZY(p);
+
+                pin_insert_group(&p->mnt_umount, &p->mnt_parent->mnt,
+                                 disconnect ? &unmounted : NULL);
                 if (mnt_has_parent(p)) {
                         mnt_add_count(p->mnt_parent, -1);
-                        umount_mnt(p);
+                        if (!disconnect) {
+                                /* Don't forget about p */
+                                list_add_tail(&p->mnt_child, &p->mnt_parent->mnt_mounts);
+                        } else {
+                                umount_mnt(p);
+                        }
                 }
                 change_mnt_propagation(p, MS_PRIVATE);
         }
@@ -1506,7 +1522,14 @@ void __detach_mounts(struct dentry *dentry)
         lock_mount_hash();
         while (!hlist_empty(&mp->m_list)) {
                 mnt = hlist_entry(mp->m_list.first, struct mount, mnt_mp_list);
-                umount_tree(mnt, 0);
+                if (mnt->mnt.mnt_flags & MNT_UMOUNT) {
+                        struct mount *p, *tmp;
+                        list_for_each_entry_safe(p, tmp, &mnt->mnt_mounts,  mnt_child) {
+                                hlist_add_head(&p->mnt_umount.s_list, &unmounted);
+                                umount_mnt(p);
+                        }
+                }
+                else umount_tree(mnt, 0);
         }
         unlock_mount_hash();
         put_mountpoint(mp);
diff --git a/fs/pnode.h b/fs/pnode.h
index 0fcdbe7ca648..7114ce6e6b9e 100644
--- a/fs/pnode.h
+++ b/fs/pnode.h
@@ -20,6 +20,8 @@
 #define SET_MNT_MARK(m) ((m)->mnt.mnt_flags |= MNT_MARKED)
 #define CLEAR_MNT_MARK(m) ((m)->mnt.mnt_flags &= ~MNT_MARKED)
 #define IS_MNT_LOCKED(m) ((m)->mnt.mnt_flags & MNT_LOCKED)
+#define IS_MNT_LOCKED_AND_LAZY(m) \
+        (((m)->mnt.mnt_flags & (MNT_LOCKED|MNT_SYNC_UMOUNT)) == MNT_LOCKED)
 
 #define CL_EXPIRE               0x01
 #define CL_SLAVE                0x02