1 files changed, 7 insertions, 0 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 6f89bcc4e555..df40b7c5f06b 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1055,6 +1055,13 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
         if (!max_to_defrag)
                 max_to_defrag = last_index - 1;
 
+        /*
+         * make writeback starts from i, so the defrag range can be
+         * written sequentially.
+         */
+        if (i < inode->i_mapping->writeback_index)
+                inode->i_mapping->writeback_index = i;
+
         while (i <= last_index && defrag_count < max_to_defrag) {
                 /*
                  * make sure we stop running if someone unmounts