btrfs: Check qgroup level in kernel qgroup assign.

Although we have qgroup level check in btrfs-progs, it's not enough
since other programe may still call ioctl directly not using
btrfs-progs. For example, systemd.

But it's btrfs-progs to be blame since we don't provide a
full-function(like subvolume create things) btrfs library with enough
check, and only rely on kernel ioctl.

So Add level checks in kernel too.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 851f235..8b851ac 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1061,6 +1061,12 @@ struct btrfs_block_group_item {
        __le64 flags;
 } __attribute__ ((__packed__));
 
+#define BTRFS_QGROUP_LEVEL_SHIFT               48
+static inline u64 btrfs_qgroup_level(u64 qgroupid)
+{
+       return qgroupid >> BTRFS_QGROUP_LEVEL_SHIFT;
+}
+
 /*
  * is subvolume quota turned on?
  */

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 464d1e2..4fb9610 100644 (file)
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -1009,6 +1009,10 @@ int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans,
        struct btrfs_qgroup_list *list;
        int ret = 0;
 
+       /* Check the level of src and dst first */
+       if (btrfs_qgroup_level(src) >= btrfs_qgroup_level(dst))
+               return -EINVAL;
+
        mutex_lock(&fs_info->qgroup_ioctl_lock);
        quota_root = fs_info->quota_root;
        if (!quota_root) {