From 4f48ef7d97d57ede733f24c622d9b12780c0472a Mon Sep 17 00:00:00 2001 From: Boris Burkov Date: Wed, 10 Jan 2024 17:51:26 -0800 Subject: [PATCH] btrfs: forbid creating subvol qgroups commit 0c309d66dacddf8ce939b891d9ead4a8e21ad6f0 upstream. Creating a qgroup 0/subvolid leads to various races and it isn't helpful, because you can't specify a subvol id when creating a subvol, so you can't be sure it will be the right one. Any requirements on the automatic subvol can be gratified by using a higher level qgroup and the inheritance parameters of subvol creation. Fixes: cecbb533b5fc ("btrfs: record simple quota deltas in delayed refs") CC: stable@vger.kernel.org # 4.14+ Reviewed-by: Qu Wenruo Signed-off-by: Boris Burkov Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/ioctl.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 908215928d6a..a26a909a5ad1 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -3810,6 +3810,11 @@ static long btrfs_ioctl_qgroup_create(struct file *file, void __user *arg) goto out; } + if (sa->create && is_fstree(sa->qgroupid)) { + ret = -EINVAL; + goto out; + } + trans = btrfs_join_transaction(root); if (IS_ERR(trans)) { ret = PTR_ERR(trans);