btrfs: move checks for DUMMY_ROOT into a helper

Signed-off-by: David Sterba <dsterba@suse.cz>
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 533657c5..ce1d71d 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1506,10 +1506,9 @@
 				   struct btrfs_root *root,
 				   struct extent_buffer *buf)
 {
-#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
-	if (unlikely(test_bit(BTRFS_ROOT_DUMMY_ROOT, &root->state)))
+	if (btrfs_test_is_dummy_root(root))
 		return 0;
-#endif
+
 	/* ensure we can see the force_cow */
 	smp_rmb();
 
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index bae025a..557fd95 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -4131,4 +4131,13 @@
 			       u64 rfer, u64 excl);
 #endif
 
+static inline int btrfs_test_is_dummy_root(struct btrfs_root *root)
+{
+#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
+	if (unlikely(test_bit(BTRFS_ROOT_DUMMY_ROOT, &root->state)))
+		return 1;
+#endif
+	return 0;
+}
+
 #endif
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 0abf4b0..14117f8 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1130,11 +1130,9 @@
 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
 						 u64 bytenr, u32 blocksize)
 {
-#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
-	if (unlikely(test_bit(BTRFS_ROOT_DUMMY_ROOT, &root->state)))
+	if (btrfs_test_is_dummy_root(root))
 		return alloc_test_extent_buffer(root->fs_info, bytenr,
 						blocksize);
-#endif
 	return alloc_extent_buffer(root->fs_info, bytenr, blocksize);
 }
 
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 44d0497..7895db9 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3073,10 +3073,10 @@
 	int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
 			    u64, u64, u64, u64, u64, u64, int);
 
-#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
-	if (unlikely(test_bit(BTRFS_ROOT_DUMMY_ROOT, &root->state)))
+
+	if (btrfs_test_is_dummy_root(root))
 		return 0;
-#endif
+
 	ref_root = btrfs_header_owner(buf);
 	nritems = btrfs_header_nritems(buf);
 	level = btrfs_header_level(buf);
@@ -6264,10 +6264,9 @@
 	int ret;
 	struct btrfs_fs_info *fs_info = root->fs_info;
 
-#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
-	if (unlikely(test_bit(BTRFS_ROOT_DUMMY_ROOT, &root->state)))
+	if (btrfs_test_is_dummy_root(root))
 		return 0;
-#endif
+
 	add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid);
 
 	/*
@@ -7336,15 +7335,14 @@
 	bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
 						 SKINNY_METADATA);
 
-#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
-	if (unlikely(test_bit(BTRFS_ROOT_DUMMY_ROOT, &root->state))) {
+	if (btrfs_test_is_dummy_root(root)) {
 		buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
 					    blocksize, level);
 		if (!IS_ERR(buf))
 			root->alloc_bytenr += blocksize;
 		return buf;
 	}
-#endif
+
 	block_rsv = use_block_rsv(trans, root, blocksize);
 	if (IS_ERR(block_rsv))
 		return ERR_CAST(block_rsv);
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index cd9717e..48b60db 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -539,10 +539,9 @@
 	struct extent_buffer *leaf;
 	struct btrfs_key key;
 
-#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
-	if (unlikely(test_bit(BTRFS_ROOT_DUMMY_ROOT, &quota_root->state)))
+	if (btrfs_test_is_dummy_root(quota_root))
 		return 0;
-#endif
+
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
@@ -698,10 +697,9 @@
 	int ret;
 	int slot;
 
-#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
-	if (unlikely(test_bit(BTRFS_ROOT_DUMMY_ROOT, &root->state)))
+	if (btrfs_test_is_dummy_root(root))
 		return 0;
-#endif
+
 	key.objectid = 0;
 	key.type = BTRFS_QGROUP_INFO_KEY;
 	key.offset = qgroup->qgroupid;