diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 68f322f600a0..3a4d19e6a8e9 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3189,6 +3189,9 @@ int btrfs_prealloc_file_range_trans(struct inode *inode,
 				    struct btrfs_trans_handle *trans, int mode,
 				    u64 start, u64 num_bytes, u64 min_size,
 				    loff_t actual_len, u64 *alloc_hint);
+int btrfs_run_delalloc_range(void *private_data, struct page *locked_page,
+		u64 start, u64 end, int *page_started, unsigned long *nr_written,
+		struct writeback_control *wbc);
 extern const struct dentry_operations btrfs_dentry_operations;
 
 /* ioctl.c */
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index d228f706ff3e..dbc42025b203 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3205,7 +3205,7 @@ static void update_nr_written(struct writeback_control *wbc,
 /*
  * helper for __extent_writepage, doing all of the delayed allocation setup.
  *
- * This returns 1 if our fill_delalloc function did all the work required
+ * This returns 1 if btrfs_run_delalloc_range function did all the work required
  * to write the page (copy into inline extent).  In this case the IO has
  * been started and the page is already unlocked.
  *
@@ -3226,7 +3226,7 @@ static noinline_for_stack int writepage_delalloc(struct inode *inode,
 	int ret;
 	int page_started = 0;
 
-	if (epd->extent_locked || !tree->ops || !tree->ops->fill_delalloc)
+	if (epd->extent_locked)
 		return 0;
 
 	while (delalloc_end < page_end) {
@@ -3239,18 +3239,16 @@ static noinline_for_stack int writepage_delalloc(struct inode *inode,
 			delalloc_start = delalloc_end + 1;
 			continue;
 		}
-		ret = tree->ops->fill_delalloc(inode, page,
-					       delalloc_start,
-					       delalloc_end,
-					       &page_started,
-					       nr_written, wbc);
+		ret = btrfs_run_delalloc_range(inode, page, delalloc_start,
+				delalloc_end, &page_started, nr_written, wbc);
 		/* File system has been set read-only */
 		if (ret) {
 			SetPageError(page);
-			/* fill_delalloc should be return < 0 for error
-			 * but just in case, we use > 0 here meaning the
-			 * IO is started, so we don't want to return > 0
-			 * unless things are going well.
+			/*
+			 * btrfs_run_delalloc_range should return < 0 for error
+			 * but just in case, we use > 0 here meaning the IO is
+			 * started, so we don't want to return > 0 unless
+			 * things are going well.
 			 */
 			ret = ret < 0 ? ret : -EIO;
 			goto done;
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 369daa5d4f73..ca48187b86ba 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -106,11 +106,6 @@ struct extent_io_ops {
 	/*
 	 * Optional hooks, called if the pointer is not NULL
 	 */
-	int (*fill_delalloc)(void *private_data, struct page *locked_page,
-			     u64 start, u64 end, int *page_started,
-			     unsigned long *nr_written,
-			     struct writeback_control *wbc);
-
 	int (*writepage_start_hook)(struct page *page, u64 start, u64 end);
 	void (*writepage_end_io_hook)(struct page *page, u64 start, u64 end,
 				      struct extent_state *state, int uptodate);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 9ea4c6f0352f..afc8704e9c78 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -109,8 +109,8 @@ static void __endio_write_update_ordered(struct inode *inode,
  * extent_clear_unlock_delalloc() to clear both the bits EXTENT_DO_ACCOUNTING
  * and EXTENT_DELALLOC simultaneously, because that causes the reserved metadata
  * to be released, which we want to happen only when finishing the ordered
- * extent (btrfs_finish_ordered_io()). Also note that the caller of the
- * fill_delalloc() callback already does proper cleanup for the first page of
+ * extent (btrfs_finish_ordered_io()). Also note that the caller of
+ * btrfs_run_delalloc_range already does proper cleanup for the first page of
  * the range, that is, it invokes the callback writepage_end_io_hook() for the
  * range of the first page.
  */
@@ -1576,12 +1576,12 @@ static inline int need_force_cow(struct inode *inode, u64 start, u64 end)
 }
 
 /*
- * extent_io.c call back to do delayed allocation processing
+ * Function to process delayed allocation (create CoW) for ranges which are
+ * being touched for the first time.
  */
-static int run_delalloc_range(void *private_data, struct page *locked_page,
-			      u64 start, u64 end, int *page_started,
-			      unsigned long *nr_written,
-			      struct writeback_control *wbc)
+int btrfs_run_delalloc_range(void *private_data, struct page *locked_page,
+		u64 start, u64 end, int *page_started, unsigned long *nr_written,
+		struct writeback_control *wbc)
 {
 	struct inode *inode = private_data;
 	int ret;
@@ -10526,7 +10526,6 @@ static const struct extent_io_ops btrfs_extent_io_ops = {
 	.readpage_io_failed_hook = btrfs_readpage_io_failed_hook,
 
 	/* optional callbacks */
-	.fill_delalloc = run_delalloc_range,
 	.writepage_end_io_hook = btrfs_writepage_end_io_hook,
 	.writepage_start_hook = btrfs_writepage_start_hook,
 	.set_bit_hook = btrfs_set_bit_hook,