Merge tag 'backport/v3.14.24-ltsi-rc1/rcar-snd-to-next-20141121' into backport/v3...

[platform/adaptation/renesas_rcar/renesas_kernel.git] / fs / namespace.c

diff --git a/fs/namespace.c b/fs/namespace.c
index fd1c914..d9bf3ef 100644 (file)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -777,6 +777,20 @@ static void attach_mnt(struct mount *mnt,
        list_add_tail(&mnt->mnt_child, &parent->mnt_mounts);
 }
 
+static void attach_shadowed(struct mount *mnt,
+                       struct mount *parent,
+                       struct mount *shadows)
+{
+       if (shadows) {
+               hlist_add_after_rcu(&shadows->mnt_hash, &mnt->mnt_hash);
+               list_add(&mnt->mnt_child, &shadows->mnt_child);
+       } else {
+               hlist_add_head_rcu(&mnt->mnt_hash,
+                               m_hash(&parent->mnt, mnt->mnt_mountpoint));
+               list_add_tail(&mnt->mnt_child, &parent->mnt_mounts);
+       }
+}
+
 /*
  * vfsmount lock must be held for write
  */
@@ -795,12 +809,7 @@ static void commit_tree(struct mount *mnt, struct mount *shadows)
 
        list_splice(&head, n->list.prev);
 
-       if (shadows)
-               hlist_add_after_rcu(&shadows->mnt_hash, &mnt->mnt_hash);
-       else
-               hlist_add_head_rcu(&mnt->mnt_hash,
-                               m_hash(&parent->mnt, mnt->mnt_mountpoint));
-       list_add_tail(&mnt->mnt_child, &parent->mnt_mounts);
+       attach_shadowed(mnt, parent, shadows);
        touch_mnt_namespace(n);
 }
 
@@ -1356,6 +1365,8 @@ static int do_umount(struct mount *mnt, int flags)
                 * Special case for "unmounting" root ...
                 * we just try to remount it readonly.
                 */
+               if (!capable(CAP_SYS_ADMIN))
+                       return -EPERM;
                down_write(&sb->s_umount);
                if (!(sb->s_flags & MS_RDONLY))
                        retval = do_remount_sb(sb, MS_RDONLY, NULL, 0);
@@ -1504,6 +1515,7 @@ struct mount *copy_tree(struct mount *mnt, struct dentry *dentry,
                        continue;
 
                for (s = r; s; s = next_mnt(s, r)) {
+                       struct mount *t = NULL;
                        if (!(flag & CL_COPY_UNBINDABLE) &&
                            IS_MNT_UNBINDABLE(s)) {
                                s = skip_mnt_tree(s);
@@ -1525,7 +1537,14 @@ struct mount *copy_tree(struct mount *mnt, struct dentry *dentry,
                                goto out;
                        lock_mount_hash();
                        list_add_tail(&q->mnt_list, &res->mnt_list);
-                       attach_mnt(q, parent, p->mnt_mp);
+                       mnt_set_mountpoint(parent, p->mnt_mp, q);
+                       if (!list_empty(&parent->mnt_mounts)) {
+                               t = list_last_entry(&parent->mnt_mounts,
+                                       struct mount, mnt_child);
+                               if (t->mnt_mp != p->mnt_mp)
+                                       t = NULL;
+                       }
+                       attach_shadowed(q, parent, t);
                        unlock_mount_hash();
                }
        }
@@ -2812,6 +2831,9 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root,
        /* make sure we can reach put_old from new_root */
        if (!is_path_reachable(old_mnt, old.dentry, &new))
                goto out4;
+       /* make certain new is below the root */
+       if (!is_path_reachable(new_mnt, new.dentry, &root))
+               goto out4;
        root_mp->m_count++; /* pin it so it won't go away */
        lock_mount_hash();
        detach_mnt(new_mnt, &parent_path);