keep shadowed vfsmounts together

preparation to switching mnt_hash to hlist

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/namespace.c b/fs/namespace.c
index 3b648da55d875cfd3543787dd662745dc70b3390..9db3ce397a838bf9e52af3c2a00528bd07935727 100644 (file)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -621,12 +621,20 @@ struct mount *__lookup_mnt(struct vfsmount *mnt, struct dentry *dentry)
 struct mount *__lookup_mnt_last(struct vfsmount *mnt, struct dentry *dentry)
 {
        struct list_head *head = m_hash(mnt, dentry);
-       struct mount *p;
+       struct mount *p, *res = NULL;
 
-       list_for_each_entry_reverse(p, head, mnt_hash)
+       list_for_each_entry(p, head, mnt_hash)
                if (&p->mnt_parent->mnt == mnt && p->mnt_mountpoint == dentry)
-                       return p;
-       return NULL;
+                       goto found;
+       return res;
+found:
+       res = p;
+       list_for_each_entry_continue(p, head, mnt_hash) {
+               if (&p->mnt_parent->mnt != mnt || p->mnt_mountpoint != dentry)
+                       break;
+               res = p;
+       }
+       return res;
 }
 
 /*
@@ -769,14 +777,14 @@ static void attach_mnt(struct mount *mnt,
                        struct mountpoint *mp)
 {
        mnt_set_mountpoint(parent, mp, mnt);
-       list_add_tail(&mnt->mnt_hash, m_hash(&parent->mnt, mp->m_dentry));
+       list_add(&mnt->mnt_hash, m_hash(&parent->mnt, mp->m_dentry));
        list_add_tail(&mnt->mnt_child, &parent->mnt_mounts);
 }
 
 /*
  * vfsmount lock must be held for write
  */
-static void commit_tree(struct mount *mnt)
+static void commit_tree(struct mount *mnt, struct mount *shadows)
 {
        struct mount *parent = mnt->mnt_parent;
        struct mount *m;
@@ -791,7 +799,10 @@ static void commit_tree(struct mount *mnt)
 
        list_splice(&head, n->list.prev);
 
-       list_add_tail(&mnt->mnt_hash,
+       if (shadows)
+               list_add(&mnt->mnt_hash, &shadows->mnt_hash);
+       else
+               list_add(&mnt->mnt_hash,
                                m_hash(&parent->mnt, mnt->mnt_mountpoint));
        list_add_tail(&mnt->mnt_child, &parent->mnt_mounts);
        touch_mnt_namespace(n);
@@ -1659,12 +1670,15 @@ static int attach_recursive_mnt(struct mount *source_mnt,
                touch_mnt_namespace(source_mnt->mnt_ns);
        } else {
                mnt_set_mountpoint(dest_mnt, dest_mp, source_mnt);
-               commit_tree(source_mnt);
+               commit_tree(source_mnt, NULL);
        }
 
        list_for_each_entry_safe(child, p, &tree_list, mnt_hash) {
+               struct mount *q;
                list_del_init(&child->mnt_hash);
-               commit_tree(child);
+               q = __lookup_mnt_last(&child->mnt_parent->mnt,
+                                     child->mnt_mountpoint);
+               commit_tree(child, q);
        }
        unlock_mount_hash();