btrfs: unexport btrfs_extent_readonly() and make it static

btrfs_extent_readonly() is used by can_nocow_extent() in inode.c. So
move it from extent-tree.c to inode.c and declare it as static.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/ctree.h

@@ -2691,7 +2691,6 @@ int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans);
 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 			 struct btrfs_ref *generic_ref);
 
-int btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr);
 void btrfs_clear_space_info_full(struct btrfs_fs_info *info);
 
 /*

fs/btrfs/extent-tree.c

@@ -2490,19 +2490,6 @@ int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 	return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
 }
 
-int btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr)
-{
-	struct btrfs_block_group *block_group;
-	int readonly = 0;
-
-	block_group = btrfs_lookup_block_group(fs_info, bytenr);
-	if (!block_group || block_group->ro)
-		readonly = 1;
-	if (block_group)
-		btrfs_put_block_group(block_group);
-	return readonly;
-}
-
 static u64 get_alloc_profile_by_root(struct btrfs_root *root, int data)
 {
 	struct btrfs_fs_info *fs_info = root->fs_info;

fs/btrfs/inode.c

@@ -7262,6 +7262,19 @@ static struct extent_map *btrfs_new_extent_direct(struct btrfs_inode *inode,
 	return em;
 }
 
+static int btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr)
+{
+	struct btrfs_block_group *block_group;
+	int readonly = 0;
+
+	block_group = btrfs_lookup_block_group(fs_info, bytenr);
+	if (!block_group || block_group->ro)
+		readonly = 1;
+	if (block_group)
+		btrfs_put_block_group(block_group);
+	return readonly;
+}
+
 /*
  * Check if we can do nocow write into the range [@offset, @offset + @len)
  *