dax: dirty inode only if required

Signed-off-by: Dmitry Monakhov <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Reviewed-by: Ross Zwisler <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Author: Dmitry Monakhov

fs/dax.c

@@ -358,7 +358,8 @@ static int dax_radix_entry(struct address_space *mapping, pgoff_t index,
 	void *entry;
 
 	WARN_ON_ONCE(pmd_entry && !dirty);
-	__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
+	if (dirty)
+		__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
 
 	spin_lock_irq(&mapping->tree_lock);