Provide a helper to fetch jinode dirty ranges in bytes. This lets
filesystem callbacks avoid depending on the internal representation,
preparing for a later conversion to page units.

Suggested-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Li Chen <me@linux.beauty>
---
Changes since v3:
- Add Reviewed-by: Jan Kara.

Changes since v2:
- New patch: add jbd2_jinode_get_dirty_range() helper.

 include/linux/jbd2.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index a53a00d36228c..64392baf5f4b4 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -445,6 +445,20 @@ struct jbd2_inode {
 	loff_t i_dirty_end;
 };
 
+static inline bool jbd2_jinode_get_dirty_range(const struct jbd2_inode *jinode,
+					       loff_t *start, loff_t *end)
+{
+	loff_t start_byte = jinode->i_dirty_start;
+	loff_t end_byte = jinode->i_dirty_end;
+
+	if (!end_byte)
+		return false;
+
+	*start = start_byte;
+	*end = end_byte;
+	return true;
+}
+
 struct jbd2_revoke_table_s;
 
 /**
-- 
2.53.0