This is a note to let you know that I've just added the patch titled btrfs: forbid deleting live subvol qgroup to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: btrfs-forbid-deleting-live-subvol-qgroup.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From a8df35619948bd8363d330c20a90c9a7fbff28c0 Mon Sep 17 00:00:00 2001 From: Boris Burkov <boris@xxxxxx> Date: Wed, 10 Jan 2024 17:30:00 -0800 Subject: btrfs: forbid deleting live subvol qgroup From: Boris Burkov <boris@xxxxxx> commit a8df35619948bd8363d330c20a90c9a7fbff28c0 upstream. If a subvolume still exists, forbid deleting its qgroup 0/subvolid. This behavior generally leads to incorrect behavior in squotas and doesn't have a legitimate purpose. Fixes: cecbb533b5fc ("btrfs: record simple quota deltas in delayed refs") CC: stable@xxxxxxxxxxxxxxx # 5.4+ Reviewed-by: Qu Wenruo <wqu@xxxxxxxx> Signed-off-by: Boris Burkov <boris@xxxxxx> Reviewed-by: David Sterba <dsterba@xxxxxxxx> Signed-off-by: David Sterba <dsterba@xxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/btrfs/qgroup.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -1608,6 +1608,15 @@ out: return ret; } +static bool qgroup_has_usage(struct btrfs_qgroup *qgroup) +{ + return (qgroup->rfer > 0 || qgroup->rfer_cmpr > 0 || + qgroup->excl > 0 || qgroup->excl_cmpr > 0 || + qgroup->rsv.values[BTRFS_QGROUP_RSV_DATA] > 0 || + qgroup->rsv.values[BTRFS_QGROUP_RSV_META_PREALLOC] > 0 || + qgroup->rsv.values[BTRFS_QGROUP_RSV_META_PERTRANS] > 0); +} + int btrfs_remove_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid) { struct btrfs_fs_info *fs_info = trans->fs_info; @@ -1627,6 +1636,11 @@ int btrfs_remove_qgroup(struct btrfs_tra goto out; } + if (is_fstree(qgroupid) && qgroup_has_usage(qgroup)) { + ret = -EBUSY; + goto out; + } + /* Check if there are no children of this qgroup */ if (!list_empty(&qgroup->members)) { ret = -EBUSY; Patches currently in stable-queue which might be from boris@xxxxxx are queue-5.10/btrfs-forbid-creating-subvol-qgroups.patch queue-5.10/btrfs-forbid-deleting-live-subvol-qgroup.patch