4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Boris Burkov <boris@xxxxxx>
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@xxxxxxxxxxxxxxx # 4.14+
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/ioctl.c | 5 +++++
1 file changed, 5 insertions(+)
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -5343,6 +5343,11 @@ static long btrfs_ioctl_qgroup_create(st
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);
