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-rw-r--r--src/librbd/io/Utils.cc57
1 files changed, 57 insertions, 0 deletions
diff --git a/src/librbd/io/Utils.cc b/src/librbd/io/Utils.cc
new file mode 100644
index 00000000..1b50561a
--- /dev/null
+++ b/src/librbd/io/Utils.cc
@@ -0,0 +1,57 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#include "librbd/io/Utils.h"
+#include "include/buffer.h"
+#include "osd/osd_types.h"
+
+namespace librbd {
+namespace io {
+namespace util {
+
+bool assemble_write_same_extent(
+ const ObjectExtent &object_extent, const ceph::bufferlist& data,
+ ceph::bufferlist *ws_data, bool force_write) {
+ size_t data_len = data.length();
+
+ if (!force_write) {
+ bool may_writesame = true;
+ for (auto& q : object_extent.buffer_extents) {
+ if (!(q.first % data_len == 0 && q.second % data_len == 0)) {
+ may_writesame = false;
+ break;
+ }
+ }
+
+ if (may_writesame) {
+ ws_data->append(data);
+ return true;
+ }
+ }
+
+ for (auto& q : object_extent.buffer_extents) {
+ bufferlist sub_bl;
+ uint64_t sub_off = q.first % data_len;
+ uint64_t sub_len = data_len - sub_off;
+ uint64_t extent_left = q.second;
+ while (extent_left >= sub_len) {
+ sub_bl.substr_of(data, sub_off, sub_len);
+ ws_data->claim_append(sub_bl);
+ extent_left -= sub_len;
+ if (sub_off) {
+ sub_off = 0;
+ sub_len = data_len;
+ }
+ }
+ if (extent_left) {
+ sub_bl.substr_of(data, sub_off, extent_left);
+ ws_data->claim_append(sub_bl);
+ }
+ }
+ return false;
+}
+
+} // namespace util
+} // namespace io
+} // namespace librbd
+