vfs: spread struct mount - attach_mnt/detach_mnt

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

1 files changed, 22 insertions, 19 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index 7226dc514b3b..444557e04b38 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -556,14 +556,14 @@ static void dentry_reset_mounted(struct dentry *dentry)
 /*
  * vfsmount lock must be held for write
  */
-static void detach_mnt(struct vfsmount *mnt, struct path *old_path)
-{
-        old_path->dentry = mnt->mnt_mountpoint;
-        old_path->mnt = mnt->mnt_parent;
-        mnt->mnt_parent = mnt;
-        mnt->mnt_mountpoint = mnt->mnt_root;
-        list_del_init(&mnt->mnt_child);
-        list_del_init(&mnt->mnt_hash);
+static void detach_mnt(struct mount *mnt, struct path *old_path)
+{
+        old_path->dentry = mnt->mnt.mnt_mountpoint;
+        old_path->mnt = mnt->mnt.mnt_parent;
+        mnt->mnt.mnt_parent = &mnt->mnt;
+        mnt->mnt.mnt_mountpoint = mnt->mnt.mnt_root;
+        list_del_init(&mnt->mnt.mnt_child);
+        list_del_init(&mnt->mnt.mnt_hash);
         dentry_reset_mounted(old_path->dentry);
 }
 
@@ -583,12 +583,12 @@ void mnt_set_mountpoint(struct vfsmount *mnt, struct dentry *dentry,
 /*
  * vfsmount lock must be held for write
  */
-static void attach_mnt(struct vfsmount *mnt, struct path *path)
+static void attach_mnt(struct mount *mnt, struct path *path)
 {
-        mnt_set_mountpoint(path->mnt, path->dentry, mnt);
-        list_add_tail(&mnt->mnt_hash, mount_hashtable +
+        mnt_set_mountpoint(path->mnt, path->dentry, &mnt->mnt);
+        list_add_tail(&mnt->mnt.mnt_hash, mount_hashtable +
                         hash(path->mnt, path->dentry));
-        list_add_tail(&mnt->mnt_child, &path->mnt->mnt_mounts);
+        list_add_tail(&mnt->mnt.mnt_child, &path->mnt->mnt_mounts);
 }
 
 static inline void __mnt_make_longterm(struct vfsmount *mnt)
@@ -1446,7 +1446,7 @@ struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry,
                                 goto Enomem;
                         br_write_lock(vfsmount_lock);
                         list_add_tail(&q->mnt_list, &res->mnt_list);
-                        attach_mnt(q, &path);
+                        attach_mnt(real_mount(q), &path);
                         br_write_unlock(vfsmount_lock);
                 }
         }
@@ -1612,8 +1612,8 @@ static int attach_recursive_mnt(struct vfsmount *source_mnt,
                         set_mnt_shared(&p->mnt);
         }
         if (parent_path) {
-                detach_mnt(source_mnt, parent_path);
-                attach_mnt(source_mnt, path);
+                detach_mnt(real_mount(source_mnt), parent_path);
+                attach_mnt(real_mount(source_mnt), path);
                 touch_mnt_namespace(parent_path->mnt->mnt_ns);
         } else {
                 mnt_set_mountpoint(dest_mnt, dest_dentry, source_mnt);
@@ -2600,6 +2600,7 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root,
                 const char __user *, put_old)
 {
         struct path new, old, parent_path, root_parent, root;
+        struct mount *new_mnt, *root_mnt;
         int error;
 
         if (!capable(CAP_SYS_ADMIN))
@@ -2623,6 +2624,8 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root,
                 goto out3;
 
         error = -EINVAL;
+        new_mnt = real_mount(new.mnt);
+        root_mnt = real_mount(root.mnt);
         if (IS_MNT_SHARED(old.mnt) ||
                 IS_MNT_SHARED(new.mnt->mnt_parent) ||
                 IS_MNT_SHARED(root.mnt->mnt_parent))
@@ -2651,12 +2654,12 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root,
         if (!is_path_reachable(old.mnt, old.dentry, &new))
                 goto out4;
         br_write_lock(vfsmount_lock);
-        detach_mnt(new.mnt, &parent_path);
-        detach_mnt(root.mnt, &root_parent);
+        detach_mnt(new_mnt, &parent_path);
+        detach_mnt(root_mnt, &root_parent);
         /* mount old root on put_old */
-        attach_mnt(root.mnt, &old);
+        attach_mnt(root_mnt, &old);
         /* mount new_root on / */
-        attach_mnt(new.mnt, &root_parent);
+        attach_mnt(new_mnt, &root_parent);
         touch_mnt_namespace(current->nsproxy->mnt_ns);
         br_write_unlock(vfsmount_lock);
         chroot_fs_refs(&root, &new);