From patchwork Fri Aug 11 01:44:35 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Lee Trager X-Patchwork-Id: 13350002 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 195C8C001DE for ; Fri, 11 Aug 2023 01:44:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230372AbjHKBo5 (ORCPT ); Thu, 10 Aug 2023 21:44:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42668 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229685AbjHKBo4 (ORCPT ); Thu, 10 Aug 2023 21:44:56 -0400 Received: from trager.us (trager.us [52.5.81.116]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 019AC10D for ; Thu, 10 Aug 2023 18:44:55 -0700 (PDT) Received: from [163.114.132.6] (helo=localhost) by trager.us with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92.3) (envelope-from ) id 1qUHCx-0006Tx-42; Fri, 11 Aug 2023 01:44:55 +0000 From: Lee Trager To: linux-btrfs@vger.kernel.org Cc: Lee Trager Subject: [PATCH] btrfs: Copy dir permission and time when creating a stub subvolume Date: Thu, 10 Aug 2023 18:44:35 -0700 Message-Id: <20230811014435.1963948-1-lee@trager.us> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org btrfs supports creating nested subvolumes however snapshots are not recursive. When a snapshot is taken of a volume which contains a subvolume the subvolume is replaced with a stub subvolume which has the same name and uses inode number 2[1]. The stub subvolume kept the directory name but did not set the time or permissions of the stub subvolume. This resulted in all time information being the current time and ownership defaulting to root. When subvolumes and snapshots are created using unshare this results in a snapshot directory the user created but has no permissions for. Test case: [vmuser@archvm ~]# sudo -i [root@archvm ~]# mkdir -p /mnt/btrfs/test [root@archvm ~]# chown vmuser:users /mnt/btrfs/test/ [root@archvm ~]# exit logout [vmuser@archvm ~]$ cd /mnt/btrfs/test [vmuser@archvm test]$ unshare --user --keep-caps --map-auto --map-root-user [root@archvm test]# btrfs subvolume create subvolume Create subvolume './subvolume' [root@archvm test]# btrfs subvolume create subvolume/subsubvolume Create subvolume 'subvolume/subsubvolume' [root@archvm test]# btrfs subvolume snapshot subvolume snapshot Create a snapshot of 'subvolume' in './snapshot' [root@archvm test]# exit logout [vmuser@archvm test]$ tree -ug [vmuser users ] . ├── [vmuser users ] snapshot │   └── [vmuser users ] subsubvolume <-- Without patch perm is root:root └── [vmuser users ] subvolume └── [vmuser users ] subsubvolume 5 directories, 0 files [1] https://btrfs.readthedocs.io/en/latest/btrfs-subvolume.html#nested-subvolumes Signed-off-by: Lee Trager --- fs/btrfs/inode.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 6a68d5a3ed20..7a288cd6f815 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -5592,11 +5592,11 @@ struct inode *btrfs_iget(struct super_block *s, u64 ino, struct btrfs_root *root return btrfs_iget_path(s, ino, root, NULL); } -static struct inode *new_simple_dir(struct super_block *s, +static struct inode *new_simple_dir(struct inode *dir, struct btrfs_key *key, struct btrfs_root *root) { - struct inode *inode = new_inode(s); + struct inode *inode = new_inode(dir->i_sb); if (!inode) return ERR_PTR(-ENOMEM); @@ -5615,9 +5615,11 @@ static struct inode *new_simple_dir(struct super_block *s, inode->i_fop = &simple_dir_operations; inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO; inode->i_mtime = current_time(inode); - inode->i_atime = inode->i_mtime; - inode->i_ctime = inode->i_mtime; + inode->i_atime = dir->i_atime; + inode->i_ctime = dir->i_ctime; BTRFS_I(inode)->i_otime = inode->i_mtime; + inode->i_uid = dir->i_uid; + inode->i_gid = dir->i_gid; return inode; } @@ -5676,7 +5678,7 @@ struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry) if (ret != -ENOENT) inode = ERR_PTR(ret); else - inode = new_simple_dir(dir->i_sb, &location, root); + inode = new_simple_dir(dir, &location, root); } else { inode = btrfs_iget(dir->i_sb, location.objectid, sub_root); btrfs_put_root(sub_root);