diff --git a/src/flb_filter.c b/src/flb_filter.c
index 853ad99a300..794bf4f719c 100644
--- a/src/flb_filter.c
+++ b/src/flb_filter.c
@@ -22,6 +22,8 @@
 #include <fluent-bit/flb_str.h>
 #include <fluent-bit/flb_env.h>
 #include <fluent-bit/flb_router.h>
+#include <fluent-bit/flb_mp.h>
+#include <fluent-bit/flb_pack.h>
 #include <chunkio/chunkio.h>
 
 static inline int instance_id(struct flb_filter_plugin *p,
@@ -62,20 +64,20 @@ void flb_filter_do(struct flb_input_chunk *ic,
     int in_records = 0;
     int out_records = 0;
     int diff = 0;
+    char *work_data;
+    size_t work_size;
     void *out_buf;
     size_t cur_size;
     size_t out_size;
     ssize_t content_size;
+    ssize_t write_at;
     struct mk_list *head;
     struct flb_filter_instance *f_ins;
     msgpack_zone *mp_zone = NULL;
 
-    content_size = cio_chunk_get_content_size(ic->chunk);
-    if (content_size <= 0) {
-        flb_error("[filter] cannot retrieve original content size");
-        return;
-    }
-    content_size -= bytes;
+
+    work_data = (char *) data;
+    work_size = bytes;
 
     /* Count number of incoming records */
     mp_zone = msgpack_zone_new(MSGPACK_ZONE_CHUNK_SIZE);
@@ -92,11 +94,17 @@ void flb_filter_do(struct flb_input_chunk *ic,
             out_buf = NULL;
             out_size = 0;
 
+            content_size = cio_chunk_get_content_size(ic->chunk);
+
+            /* where to position the new content if modified ? */
+            write_at = (content_size - work_size);
+
             /* Count number of incoming records */
             in_records = flb_mp_count_zone(data, bytes, mp_zone);
 
             /* Invoke the filter callback */
-            ret = f_ins->p->cb_filter(data, bytes,    /* msgpack raw data */
+            ret = f_ins->p->cb_filter(work_data,      /* msgpack buffer   */
+                                      work_size,      /* msgpack size     */
                                       tag, tag_len,   /* input tag        */
                                       &out_buf,       /* new data         */
                                       &out_size,      /* new data size    */
@@ -122,9 +130,7 @@ void flb_filter_do(struct flb_input_chunk *ic,
                 }
                 else {
 #ifdef FLB_HAVE_METRICS
-                    out_records = flb_mp_count_zone(out_buf, out_size,
-                                                    mp_zone);
-
+                    out_records = flb_mp_count_zone(out_buf, out_size, mp_zone);
                     if (out_records > in_records) {
                         diff = (out_records - in_records);
                         /* Summarize new records */
@@ -137,16 +143,18 @@ void flb_filter_do(struct flb_input_chunk *ic,
                         flb_metrics_sum(FLB_METRIC_N_DROPPED,
                                         diff, f_ins->metrics);
                     }
-                    msgpack_zone_clear(mp_zone);
 #endif
                 }
-                ret = flb_input_chunk_write_at(ic, content_size,
+                msgpack_zone_clear(mp_zone);
+
+                ret = flb_input_chunk_write_at(ic, write_at,
                                                out_buf, out_size);
                 /* Point back the 'data' pointer to the new address */
-                bytes = out_size;
                 ret = cio_chunk_get_content(ic->chunk,
-                                            data, &cur_size);
-                data += content_size;
+                                            &work_data, &cur_size);
+
+                work_data += (cur_size - out_size);
+                work_size = out_size;
                 flb_free(out_buf);
             }
         }