Add helper APIs needed by filesystems to avoid poking into writeback
internals.

Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kundan Kumar <kundan.kumar@samsung.com>
Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
---
 include/linux/backing-dev.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 0c8342747cab..5b7d12b40d5e 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -136,6 +136,19 @@ static inline bool mapping_can_writeback(struct address_space *mapping)
 	return inode_to_bdi(mapping->host)->capabilities & BDI_CAP_WRITEBACK;
 }
 
+/* Must not be used by file systems that support cgroup writeback */
+static inline int bdi_wb_dirty_exceeded(struct backing_dev_info *bdi)
+{
+	return bdi->wb.dirty_exceeded;
+}
+
+/* Must not be used by file systems that support cgroup writeback */
+static inline void bdi_wb_stat_mod(struct inode *inode, enum wb_stat_item item,
+				   s64 amount)
+{
+	wb_stat_mod(&inode_to_bdi(inode)->wb, item, amount);
+}
+
 #ifdef CONFIG_CGROUP_WRITEBACK
 
 struct bdi_writeback *wb_get_lookup(struct backing_dev_info *bdi,
-- 
2.25.1