Adding upstream version 18.2.2.upstream/18.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 195 insertions, 0 deletions

diff --git a/src/test/erasure-code/ErasureCodeExample.h b/src/test/erasure-code/ErasureCodeExample.h
new file mode 100644
index 000000000..4226361c4
--- /dev/null
+++ b/src/test/erasure-code/ErasureCodeExample.h
@@ -0,0 +1,195 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*- 
+// vim: ts=8 sw=2 smarttab
+/*
+ * Ceph distributed storage system
+ *
+ * Copyright (C) 2013 Cloudwatt <libre.licensing@cloudwatt.com>
+ *
+ * Author: Loic Dachary <loic@dachary.org>
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ * 
+ */
+
+#ifndef CEPH_ERASURE_CODE_EXAMPLE_H
+#define CEPH_ERASURE_CODE_EXAMPLE_H
+
+#include <unistd.h>
+#include <errno.h>
+#include <algorithm>
+#include <sstream>
+
+#include "crush/CrushWrapper.h"
+#include "osd/osd_types.h"
+#include "erasure-code/ErasureCode.h"
+
+#define FIRST_DATA_CHUNK 0
+#define SECOND_DATA_CHUNK 1
+#define DATA_CHUNKS 2u
+
+#define CODING_CHUNK 2
+#define CODING_CHUNKS 1u
+
+#define MINIMUM_TO_RECOVER 2u
+
+class ErasureCodeExample final : public ErasureCode {
+public:
+  ~ErasureCodeExample() override {}
+
+  int create_rule(const std::string &name,
+			     CrushWrapper &crush,
+		             std::ostream *ss) const override {
+    return crush.add_simple_rule(name, "default", "host", "",
+				 "indep", pg_pool_t::TYPE_ERASURE, ss);
+  }
+
+  int minimum_to_decode_with_cost(const std::set<int> &want_to_read,
+                                          const std::map<int, int> &available,
+                                          std::set<int> *minimum) override {
+    //
+    // If one chunk is more expensive to fetch than the others,
+    // recover it instead. For instance, if the cost reflects the
+    // time it takes for a chunk to be retrieved from a remote
+    // OSD and if CPU is cheap, it could make sense to recover
+    // instead of fetching the chunk.
+    //
+    std::map<int, int> c2c(available);
+    if (c2c.size() > DATA_CHUNKS) {
+      if (c2c[FIRST_DATA_CHUNK] > c2c[SECOND_DATA_CHUNK] &&
+	  c2c[FIRST_DATA_CHUNK] > c2c[CODING_CHUNK])
+	c2c.erase(FIRST_DATA_CHUNK);
+      else if(c2c[SECOND_DATA_CHUNK] > c2c[FIRST_DATA_CHUNK] &&
+	      c2c[SECOND_DATA_CHUNK] > c2c[CODING_CHUNK])
+	c2c.erase(SECOND_DATA_CHUNK);
+      else if(c2c[CODING_CHUNK] > c2c[FIRST_DATA_CHUNK] &&
+	      c2c[CODING_CHUNK] > c2c[SECOND_DATA_CHUNK])
+	c2c.erase(CODING_CHUNK);
+    }
+    std::set <int> available_chunks;
+    for (std::map<int, int>::const_iterator i = c2c.begin();
+	 i != c2c.end();
+	 ++i)
+      available_chunks.insert(i->first);
+    return _minimum_to_decode(want_to_read, available_chunks, minimum);
+  }
+
+  unsigned int get_chunk_count() const override {
+    return DATA_CHUNKS + CODING_CHUNKS;
+  }
+
+  unsigned int get_data_chunk_count() const override {
+    return DATA_CHUNKS;
+  }
+
+  unsigned int get_chunk_size(unsigned int object_size) const override {
+    return ( object_size / DATA_CHUNKS ) + 1;
+  }
+
+  int encode(const std::set<int> &want_to_encode,
+                     const bufferlist &in,
+                     std::map<int, bufferlist> *encoded) override {
+    //
+    // make sure all data chunks have the same length, allocating
+    // padding if necessary.
+    //
+    unsigned int chunk_length = get_chunk_size(in.length());
+    bufferlist out(in);
+    unsigned int width = get_chunk_count() * get_chunk_size(in.length());
+    bufferptr pad(width - in.length());
+    pad.zero(0, get_data_chunk_count());
+    out.push_back(pad);
+    //
+    // compute the coding chunk with first chunk ^ second chunk
+    //
+    char *p = out.c_str();
+    for (unsigned i = 0; i < chunk_length; i++)
+      p[i + CODING_CHUNK * chunk_length] =
+        p[i + FIRST_DATA_CHUNK * chunk_length] ^
+	p[i + SECOND_DATA_CHUNK * chunk_length];
+    //
+    // populate the bufferlist with bufferptr pointing
+    // to chunk boundaries
+    //
+    const bufferptr &ptr = out.front();
+    for (auto j = want_to_encode.begin();
+         j != want_to_encode.end();
+         ++j) {
+      bufferlist tmp;
+      bufferptr chunk(ptr, (*j) * chunk_length, chunk_length);
+      tmp.push_back(chunk);
+      tmp.claim_append((*encoded)[*j]);
+      (*encoded)[*j].swap(tmp);
+    }
+    return 0;
+  }
+
+  int encode_chunks(const std::set<int> &want_to_encode,
+			    std::map<int, bufferlist> *encoded) override {
+    ceph_abort();
+    return 0;
+  }
+
+  int _decode(const std::set<int> &want_to_read,
+	      const std::map<int, bufferlist> &chunks,
+	      std::map<int, bufferlist> *decoded) override {
+    //
+    // All chunks have the same size
+    //
+    unsigned chunk_length = (*chunks.begin()).second.length();
+    for (std::set<int>::iterator i = want_to_read.begin();
+         i != want_to_read.end();
+         ++i) {
+      if (chunks.find(*i) != chunks.end()) {
+	//
+	// If the chunk is available, just copy the bufferptr pointer
+	// to the decoded argument.
+	//
+        (*decoded)[*i] = chunks.find(*i)->second;
+      } else if(chunks.size() != 2) {
+	//
+	// If a chunk is missing and there are not enough chunks
+	// to recover, abort.
+	//
+	return -ERANGE;
+      } else {
+	//
+	// No matter what the missing chunk is, XOR of the other
+	// two recovers it.
+	//
+        std::map<int, bufferlist>::const_iterator k = chunks.begin();
+        const char *a = k->second.front().c_str();
+        ++k;
+        const char *b = k->second.front().c_str();
+        bufferptr chunk(chunk_length);
+	char *c = chunk.c_str();
+        for (unsigned j = 0; j < chunk_length; j++) {
+          c[j] = a[j] ^ b[j];
+        }
+
+	bufferlist tmp;
+	tmp.append(chunk);
+	tmp.claim_append((*decoded)[*i]);
+	(*decoded)[*i].swap(tmp);
+      }
+    }
+    return 0;
+  }
+
+  int decode_chunks(const std::set<int> &want_to_read,
+			    const std::map<int, bufferlist> &chunks,
+			    std::map<int, bufferlist> *decoded) override {
+    ceph_abort();
+    return 0;
+  }
+
+  const std::vector<int> &get_chunk_mapping() const override {
+    static std::vector<int> mapping;
+    return mapping;
+  }
+
+};
+
+#endif