diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 783906c..dbefa6c 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2572,6 +2572,11 @@
 	if (off + len == src->i_size)
 		len = ALIGN(src->i_size, bs) - off;
 
+	if (len == 0) {
+		ret = 0;
+		goto out_unlock;
+	}
+
 	/* verify the end result is block aligned */
 	if (!IS_ALIGNED(off, bs) || !IS_ALIGNED(off + len, bs) ||
 	    !IS_ALIGNED(destoff, bs))