1 files changed, 76 insertions, 0 deletions
diff --git a/src/common/SloppyCRCMap.h b/src/common/SloppyCRCMap.h
new file mode 100644
index 000000000..6bbfe978a
--- /dev/null
+++ b/src/common/SloppyCRCMap.h
@@ -0,0 +1,76 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*- 
+// vim: ts=8 sw=2 smarttab
+
+#ifndef CEPH_COMMON_SLOPPYCRCMAP_H
+#define CEPH_COMMON_SLOPPYCRCMAP_H
+
+#include "include/encoding.h"
+
+namespace ceph {
+class Formatter;
+}
+
+/**
+ * SloppyCRCMap
+ *
+ * Opportunistically track CRCs on any reads or writes that cover full
+ * blocks.  Verify read results when we have CRC data available for
+ * the given extent.
+ */
+class SloppyCRCMap {
+  static const int crc_iv = 0xffffffff;
+
+  std::map<uint64_t, uint32_t> crc_map;  // offset -> crc(-1)
+  uint32_t block_size;
+  uint32_t zero_crc;
+
+public:
+  SloppyCRCMap(uint32_t b=0) {
+    set_block_size(b);
+  }
+
+  void set_block_size(uint32_t b) {
+    block_size = b;
+    //zero_crc = ceph_crc32c(0xffffffff, NULL, block_size);
+    if (b) {
+      ceph::buffer::list bl;
+      bl.append_zero(block_size);
+      zero_crc = bl.crc32c(crc_iv);
+    } else {
+      zero_crc = crc_iv;
+    }
+  }
+
+  /// update based on a write
+  void write(uint64_t offset, uint64_t len, const ceph::buffer::list& bl,
+	     std::ostream *out = NULL);
+
+  /// update based on a truncate
+  void truncate(uint64_t offset);
+
+  /// update based on a zero/punch_hole
+  void zero(uint64_t offset, uint64_t len);
+
+  /// update based on a zero/punch_hole
+  void clone_range(uint64_t offset, uint64_t len, uint64_t srcoff, const SloppyCRCMap& src,
+		   std::ostream *out = NULL);
+
+  /**
+   * validate a read result
+   *
+   * @param offset offset
+   * @param length length
+   * @param bl data read
+   * @param err option ostream to describe errors in detail
+   * @returns error count, 0 for success
+   */
+  int read(uint64_t offset, uint64_t len, const ceph::buffer::list& bl, std::ostream *err);
+
+  void encode(ceph::buffer::list& bl) const;
+  void decode(ceph::buffer::list::const_iterator& bl);
+  void dump(ceph::Formatter *f) const;
+  static void generate_test_instances(std::list<SloppyCRCMap*>& ls);
+};
+WRITE_CLASS_ENCODER(SloppyCRCMap)
+
+#endif