1 files changed, 10 insertions, 1 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 538f65a79ec..dae5dfe41ba 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1047,7 +1047,16 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
         if (!max_to_defrag)
                 max_to_defrag = last_index - 1;
 
-        while (i <= last_index && defrag_count < max_to_defrag) {
+        /*
+         * 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 &&
+               (i < (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
+                PAGE_CACHE_SHIFT)) {
                 /*
                  * make sure we stop running if someone unmounts
                  * the FS