osd/ECUtil: add ec encode/decode util helpers

Signed-off-by: Samuel Just <sam.just@inktank.com>

1 files changed, 154 insertions, 0 deletions

diff --git a/src/osd/ECUtil.h b/src/osd/ECUtil.h
new file mode 100644
index 00000000000..4952ed8be34
--- /dev/null
+++ b/src/osd/ECUtil.h
@@ -0,0 +1,154 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2013 Inktank Storage, Inc.
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software
+ * Foundation.  See file COPYING.
+ *
+ */
+
+#ifndef ECUTIL_H
+#define ECUTIL_H
+
+#include <map>
+#include <set>
+
+#include <memory>
+#include "erasure-code/ErasureCodeInterface.h"
+#include "include/buffer.h"
+#include "include/assert.h"
+#include "include/encoding.h"
+#include "common/Formatter.h"
+
+namespace ECUtil {
+
+const uint64_t CHUNK_ALIGNMENT = 64;
+const uint64_t CHUNK_INFO = 8;
+const uint64_t CHUNK_PADDING = 8;
+const uint64_t CHUNK_OVERHEAD = 16; // INFO + PADDING
+
+class stripe_info_t {
+  const uint64_t stripe_size;
+  const uint64_t stripe_width;
+  const uint64_t chunk_size;
+public:
+  stripe_info_t(uint64_t stripe_size, uint64_t stripe_width)
+    : stripe_size(stripe_size), stripe_width(stripe_width),
+      chunk_size(stripe_width / stripe_size) {
+    assert(stripe_width % stripe_size == 0);
+  }
+  uint64_t get_stripe_width() const {
+    return stripe_width;
+  }
+  uint64_t get_chunk_size() const {
+    return chunk_size;
+  }
+  uint64_t logical_to_prev_chunk_offset(uint64_t offset) const {
+    return (offset / stripe_width) * chunk_size;
+  }
+  uint64_t logical_to_next_chunk_offset(uint64_t offset) const {
+    return ((offset + stripe_width - 1)/ stripe_width) * chunk_size;
+  }
+  uint64_t logical_to_prev_stripe_offset(uint64_t offset) const {
+    return offset - (offset % stripe_width);
+  }
+  uint64_t logical_to_next_stripe_offset(uint64_t offset) const {
+    return offset % stripe_width ?
+      offset - (offset % stripe_width) + stripe_width :
+      offset;
+  }
+  uint64_t aligned_logical_offset_to_chunk_offset(uint64_t offset) const {
+    assert(offset % stripe_width == 0);
+    return (offset / stripe_width) * chunk_size;
+  }
+  uint64_t aligned_chunk_offset_to_logical_offset(uint64_t offset) const {
+    assert(offset % chunk_size == 0);
+    return (offset / chunk_size) * stripe_width;
+  }
+  pair<uint64_t, uint64_t> aligned_offset_len_to_chunk(
+    pair<uint64_t, uint64_t> in) const {
+    return make_pair(
+      aligned_logical_offset_to_chunk_offset(in.first),
+      aligned_logical_offset_to_chunk_offset(in.second));
+  }
+  pair<uint64_t, uint64_t> offset_len_to_stripe_bounds(
+    pair<uint64_t, uint64_t> in) const {
+    uint64_t off = logical_to_prev_stripe_offset(in.first);
+    uint64_t len = logical_to_next_stripe_offset(
+      (in.first - off) + in.second);
+    return make_pair(off, len);
+  }
+};
+
+int decode(
+  const stripe_info_t &sinfo,
+  ErasureCodeInterfaceRef &ec_impl,
+  map<int, bufferlist> &to_decode,
+  bufferlist *out);
+
+int decode(
+  const stripe_info_t &sinfo,
+  ErasureCodeInterfaceRef &ec_impl,
+  map<int, bufferlist> &to_decode,
+  map<int, bufferlist*> &out);
+
+int encode(
+  const stripe_info_t &sinfo,
+  ErasureCodeInterfaceRef &ec_impl,
+  bufferlist &in,
+  const set<int> &want,
+  map<int, bufferlist> *out);
+
+class HashInfo {
+  uint64_t total_chunk_size;
+  vector<uint32_t> cumulative_shard_hashes;
+public:
+  HashInfo() : total_chunk_size(0) {}
+  HashInfo(unsigned num_chunks)
+  : total_chunk_size(0),
+    cumulative_shard_hashes(num_chunks, -1) {}
+  void append(uint64_t old_size, map<int, bufferlist> &to_append) {
+    assert(to_append.size() == cumulative_shard_hashes.size());
+    assert(old_size == total_chunk_size);
+    uint64_t size_to_append = to_append.begin()->second.length();
+    for (map<int, bufferlist>::iterator i = to_append.begin();
+	 i != to_append.end();
+	 ++i) {
+      assert(size_to_append == i->second.length());
+      assert((unsigned)i->first < cumulative_shard_hashes.size());
+      uint32_t new_hash = i->second.crc32c(cumulative_shard_hashes[i->first]);
+      cumulative_shard_hashes[i->first] = new_hash;
+    }
+    total_chunk_size += size_to_append;
+  }
+  void clear() {
+    total_chunk_size = 0;
+    cumulative_shard_hashes = vector<uint32_t>(
+      cumulative_shard_hashes.size(),
+      0);
+  }
+  void encode(bufferlist &bl) const;
+  void decode(bufferlist::iterator &bl);
+  void dump(Formatter *f) const;
+  static void generate_test_instances(list<HashInfo*>& o);
+  uint32_t get_chunk_hash(int shard) const {
+    assert((unsigned)shard < cumulative_shard_hashes.size());
+    return cumulative_shard_hashes[shard];
+  }
+  uint64_t get_total_chunk_size() const {
+    return total_chunk_size;
+  }
+};
+typedef std::tr1::shared_ptr<HashInfo> HashInfoRef;
+
+bool is_hinfo_key_string(const string &key);
+const string &get_hinfo_key();
+
+};
+WRITE_CLASS_ENCODER(ECUtil::HashInfo)
+#endif