ErasureCodeJerasure: define technique Liberation

technique == "liberation"

parse : default to K=7, M=2 and W=7 and packetsize = 8.
If any of the following constraints is not satisfied, revert to the
default:

 * K > W
 * W > 2
 * W is a prime number
 * packetsize must not be zero
 * packetsize must be a multiple of sizeof(int)

pad_in_length : pad to a multiple of k*w*packetsize*sizeof(int)

prepare, jerasure_encode, jerasure_decode map directly to the matching
jerasure functions

https://github.com/dachary/ceph/tree/wip-5879 refs #5879

Signed-off-by: Loic Dachary <loic@dachary.org>

src/osd/ErasureCodePluginJerasure/ErasureCodeJerasure.cc

@@ -284,3 +284,68 @@ void ErasureCodeJerasureCauchyGood::prepare() {
   prepare_schedule(matrix);
   free(matrix);
 }
+
+// 
+// ErasureCodeJerasureLiberation
+//
+ErasureCodeJerasureLiberation::~ErasureCodeJerasureLiberation() {
+  if (bitmatrix)
+    free(bitmatrix);
+  if (schedule)
+    jerasure_free_schedule(schedule);
+}
+
+void ErasureCodeJerasureLiberation::jerasure_encode(char **data,
+                                                    char **coding,
+                                                    int blocksize) {
+  jerasure_schedule_encode(k, m, w, schedule, data, coding, blocksize, packetsize);
+}
+
+int ErasureCodeJerasureLiberation::jerasure_decode(int *erasures,
+                                                    char **data,
+                                                    char **coding,
+                                                    int blocksize) {
+  return jerasure_schedule_decode_lazy(k, m, w, bitmatrix, erasures, data, coding, blocksize, packetsize, 1);
+}
+
+unsigned ErasureCodeJerasureLiberation::pad_in_length(unsigned in_length) {
+  while (in_length%(k*w*packetsize*sizeof(int)) != 0) 
+    in_length++;
+  return in_length;
+}
+
+void ErasureCodeJerasureLiberation::parse(const map<std::string,std::string> &parameters) {
+  k = to_int("erasure-code-k", parameters, DEFAULT_K);
+  m = to_int("erasure-code-m", parameters, DEFAULT_M);
+  w = to_int("erasure-code-w", parameters, DEFAULT_W);
+  packetsize = to_int("erasure-code-packetsize", parameters, DEFAULT_PACKETSIZE);
+
+  bool error = false;
+  if (k > w) {
+    derr << "k=" << k << " must be less than or equal to w=" << w << dendl;
+    error = true;
+  }
+  if (w <= 2 || !is_prime(w)) {
+    derr <<  "w=" << w << " must be greater than two and be prime" << dendl;
+    error = true;
+  }
+  if (packetsize == 0) {
+    derr << "packetsize=" << packetsize << " must be set" << dendl;
+    error = true;
+  }
+  if ((packetsize%(sizeof(int))) != 0) {
+    derr << "packetsize=" << packetsize << " must be a multiple of sizeof(int) = " << sizeof(int) << dendl;
+    error = true;
+  }
+  if (error) {
+    derr << "reverting to k=" << DEFAULT_K << ", w=" << DEFAULT_W << ", packetsize=" << DEFAULT_PACKETSIZE << dendl;
+    k = DEFAULT_K;
+    w = DEFAULT_W;
+    packetsize = DEFAULT_PACKETSIZE;
+  }
+}
+
+void ErasureCodeJerasureLiberation::prepare() {
+  bitmatrix = liberation_coding_bitmatrix(k, w);
+  schedule = jerasure_smart_bitmatrix_to_schedule(k, m, w, bitmatrix);
+}

src/osd/ErasureCodePluginJerasure/ErasureCodeJerasure.h

@@ -171,4 +171,33 @@ public:
 
   virtual void prepare();
 };
+
+class ErasureCodeJerasureLiberation : public ErasureCodeJerasure {
+public:
+  static const int DEFAULT_K = 2;
+  static const int DEFAULT_M = 2;
+  static const int DEFAULT_W = 7;
+  static const int DEFAULT_PACKETSIZE = 8;
+  int *bitmatrix;
+  int **schedule;
+  int packetsize;
+
+  ErasureCodeJerasureLiberation(const char *technique = "liberation") :
+    ErasureCodeJerasure(technique),
+    bitmatrix(0),
+    schedule(0)
+  { }
+  virtual ~ErasureCodeJerasureLiberation();
+
+  virtual void jerasure_encode(char **data,
+                               char **coding,
+                               int blocksize);
+  virtual int jerasure_decode(int *erasures,
+                               char **data,
+                               char **coding,
+                               int blocksize);
+  virtual unsigned pad_in_length(unsigned in_length);
+  virtual void parse(const map<std::string,std::string> &parameters);
+  virtual void prepare();
+};
 #endif

src/test/osd/TestErasureCodeJerasure.cc

@@ -30,6 +30,7 @@ typedef ::testing::Types<
   ErasureCodeJerasureReedSolomonRAID6,
   ErasureCodeJerasureCauchyOrig,
   ErasureCodeJerasureCauchyGood,
+  ErasureCodeJerasureLiberation,
 > JerasureTypes;
 TYPED_TEST_CASE(ErasureCodeTest, JerasureTypes);