btrfs: qgroup: introduce quota mode

In preparation for introducing simple quotas, change from a binary
setting for quotas to an enum based mode. Initially, the possible modes
are disabled/full. Full quotas is normal btrfs qgroups.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/qgroup.c

@@ -30,6 +30,13 @@
 #include "root-tree.h"
 #include "tree-checker.h"
 
+enum btrfs_qgroup_mode btrfs_qgroup_mode(struct btrfs_fs_info *fs_info)
+{
+	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
+		return BTRFS_QGROUP_MODE_DISABLED;
+	return BTRFS_QGROUP_MODE_FULL;
+}
+
 /*
  * Helpers to access qgroup reservation
  *

fs/btrfs/qgroup.h

@@ -277,6 +277,12 @@ enum {
 };
 
 int btrfs_quota_enable(struct btrfs_fs_info *fs_info);
+enum btrfs_qgroup_mode {
+	BTRFS_QGROUP_MODE_DISABLED,
+	BTRFS_QGROUP_MODE_FULL,
+};
+
+enum btrfs_qgroup_mode btrfs_qgroup_mode(struct btrfs_fs_info *fs_info);
 int btrfs_quota_disable(struct btrfs_fs_info *fs_info);
 int btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info);
 void btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info);