[PATCH] get rid of more nameidata passing in namespace.c
Further reduction of stack footprint (sys_pivot_root()); lose useless BKL in there, while we are at it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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b5266eb4c8
commit
8c3ee42e80
1 changed files with 25 additions and 28 deletions
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@ -1205,32 +1205,32 @@ static int attach_recursive_mnt(struct vfsmount *source_mnt,
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return 0;
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}
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static int graft_tree(struct vfsmount *mnt, struct nameidata *nd)
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static int graft_tree(struct vfsmount *mnt, struct path *path)
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{
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int err;
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if (mnt->mnt_sb->s_flags & MS_NOUSER)
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return -EINVAL;
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if (S_ISDIR(nd->path.dentry->d_inode->i_mode) !=
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if (S_ISDIR(path->dentry->d_inode->i_mode) !=
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S_ISDIR(mnt->mnt_root->d_inode->i_mode))
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return -ENOTDIR;
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err = -ENOENT;
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mutex_lock(&nd->path.dentry->d_inode->i_mutex);
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if (IS_DEADDIR(nd->path.dentry->d_inode))
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mutex_lock(&path->dentry->d_inode->i_mutex);
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if (IS_DEADDIR(path->dentry->d_inode))
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goto out_unlock;
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err = security_sb_check_sb(mnt, &nd->path);
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err = security_sb_check_sb(mnt, path);
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if (err)
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goto out_unlock;
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err = -ENOENT;
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if (IS_ROOT(nd->path.dentry) || !d_unhashed(nd->path.dentry))
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err = attach_recursive_mnt(mnt, &nd->path, NULL);
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if (IS_ROOT(path->dentry) || !d_unhashed(path->dentry))
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err = attach_recursive_mnt(mnt, path, NULL);
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out_unlock:
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mutex_unlock(&nd->path.dentry->d_inode->i_mutex);
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mutex_unlock(&path->dentry->d_inode->i_mutex);
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if (!err)
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security_sb_post_addmount(mnt, &nd->path);
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security_sb_post_addmount(mnt, path);
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return err;
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}
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@ -1294,7 +1294,7 @@ static noinline int do_loopback(struct nameidata *nd, char *old_name,
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if (!mnt)
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goto out;
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err = graft_tree(mnt, nd);
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err = graft_tree(mnt, &nd->path);
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if (err) {
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LIST_HEAD(umount_list);
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spin_lock(&vfsmount_lock);
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@ -1501,7 +1501,7 @@ int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd,
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goto unlock;
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newmnt->mnt_flags = mnt_flags;
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if ((err = graft_tree(newmnt, nd)))
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if ((err = graft_tree(newmnt, &nd->path)))
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goto unlock;
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if (fslist) /* add to the specified expiration list */
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@ -1987,15 +1987,13 @@ asmlinkage long sys_pivot_root(const char __user * new_root,
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const char __user * put_old)
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{
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struct vfsmount *tmp;
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struct nameidata new_nd, old_nd, user_nd;
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struct path parent_path, root_parent;
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struct nameidata new_nd, old_nd;
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struct path parent_path, root_parent, root;
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int error;
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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lock_kernel();
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error = __user_walk(new_root, LOOKUP_FOLLOW | LOOKUP_DIRECTORY,
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&new_nd);
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if (error)
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@ -2015,7 +2013,7 @@ asmlinkage long sys_pivot_root(const char __user * new_root,
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}
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read_lock(¤t->fs->lock);
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user_nd.path = current->fs->root;
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root = current->fs->root;
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path_get(¤t->fs->root);
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read_unlock(¤t->fs->lock);
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down_write(&namespace_sem);
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@ -2023,9 +2021,9 @@ asmlinkage long sys_pivot_root(const char __user * new_root,
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error = -EINVAL;
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if (IS_MNT_SHARED(old_nd.path.mnt) ||
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IS_MNT_SHARED(new_nd.path.mnt->mnt_parent) ||
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IS_MNT_SHARED(user_nd.path.mnt->mnt_parent))
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IS_MNT_SHARED(root.mnt->mnt_parent))
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goto out2;
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if (!check_mnt(user_nd.path.mnt))
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if (!check_mnt(root.mnt))
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goto out2;
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error = -ENOENT;
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if (IS_DEADDIR(new_nd.path.dentry->d_inode))
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@ -2035,13 +2033,13 @@ asmlinkage long sys_pivot_root(const char __user * new_root,
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if (d_unhashed(old_nd.path.dentry) && !IS_ROOT(old_nd.path.dentry))
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goto out2;
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error = -EBUSY;
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if (new_nd.path.mnt == user_nd.path.mnt ||
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old_nd.path.mnt == user_nd.path.mnt)
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if (new_nd.path.mnt == root.mnt ||
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old_nd.path.mnt == root.mnt)
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goto out2; /* loop, on the same file system */
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error = -EINVAL;
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if (user_nd.path.mnt->mnt_root != user_nd.path.dentry)
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if (root.mnt->mnt_root != root.dentry)
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goto out2; /* not a mountpoint */
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if (user_nd.path.mnt->mnt_parent == user_nd.path.mnt)
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if (root.mnt->mnt_parent == root.mnt)
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goto out2; /* not attached */
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if (new_nd.path.mnt->mnt_root != new_nd.path.dentry)
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goto out2; /* not a mountpoint */
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@ -2063,27 +2061,26 @@ asmlinkage long sys_pivot_root(const char __user * new_root,
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} else if (!is_subdir(old_nd.path.dentry, new_nd.path.dentry))
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goto out3;
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detach_mnt(new_nd.path.mnt, &parent_path);
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detach_mnt(user_nd.path.mnt, &root_parent);
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detach_mnt(root.mnt, &root_parent);
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/* mount old root on put_old */
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attach_mnt(user_nd.path.mnt, &old_nd.path);
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attach_mnt(root.mnt, &old_nd.path);
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/* mount new_root on / */
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attach_mnt(new_nd.path.mnt, &root_parent);
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touch_mnt_namespace(current->nsproxy->mnt_ns);
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spin_unlock(&vfsmount_lock);
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chroot_fs_refs(&user_nd.path, &new_nd.path);
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security_sb_post_pivotroot(&user_nd.path, &new_nd.path);
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chroot_fs_refs(&root, &new_nd.path);
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security_sb_post_pivotroot(&root, &new_nd.path);
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error = 0;
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path_put(&root_parent);
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path_put(&parent_path);
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out2:
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mutex_unlock(&old_nd.path.dentry->d_inode->i_mutex);
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up_write(&namespace_sem);
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path_put(&user_nd.path);
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path_put(&root);
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path_put(&old_nd.path);
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out1:
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path_put(&new_nd.path);
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out0:
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unlock_kernel();
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return error;
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out3:
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spin_unlock(&vfsmount_lock);
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