Adding upstream version 14.2.21.upstream/14.2.21upstream

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

1 files changed, 236 insertions, 0 deletions

diff --git a/src/osd/SnapMapper.h b/src/osd/SnapMapper.h
new file mode 100644
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--- /dev/null
+++ b/src/osd/SnapMapper.h
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+// -*- 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 SNAPMAPPER_H
+#define SNAPMAPPER_H
+
+#include <string>
+#include <set>
+#include <utility>
+#include <string.h>
+
+#include "common/map_cacher.hpp"
+#include "common/hobject.h"
+#include "include/buffer.h"
+#include "include/encoding.h"
+#include "include/object.h"
+#include "os/ObjectStore.h"
+
+class OSDriver : public MapCacher::StoreDriver<std::string, bufferlist> {
+  ObjectStore *os;
+  ObjectStore::CollectionHandle ch;
+  ghobject_t hoid;
+
+public:
+  class OSTransaction : public MapCacher::Transaction<std::string, bufferlist> {
+    friend class OSDriver;
+    coll_t cid;
+    ghobject_t hoid;
+    ObjectStore::Transaction *t;
+    OSTransaction(
+      const coll_t &cid,
+      const ghobject_t &hoid,
+      ObjectStore::Transaction *t)
+      : cid(cid), hoid(hoid), t(t) {}
+  public:
+    void set_keys(
+      const std::map<std::string, bufferlist> &to_set) override {
+      t->omap_setkeys(cid, hoid, to_set);
+    }
+    void remove_keys(
+      const std::set<std::string> &to_remove) override {
+      t->omap_rmkeys(cid, hoid, to_remove);
+    }
+    void add_callback(
+      Context *c) override {
+      t->register_on_applied(c);
+    }
+  };
+
+  OSTransaction get_transaction(
+    ObjectStore::Transaction *t) {
+    return OSTransaction(ch->cid, hoid, t);
+  }
+
+  OSDriver(ObjectStore *os, const coll_t& cid, const ghobject_t &hoid) :
+    os(os),
+    hoid(hoid) {
+    ch = os->open_collection(cid);
+  }
+  int get_keys(
+    const std::set<std::string> &keys,
+    std::map<std::string, bufferlist> *out) override;
+  int get_next(
+    const std::string &key,
+    pair<std::string, bufferlist> *next) override;
+};
+
+/**
+ * SnapMapper
+ *
+ * Manages two mappings:
+ *  1) hobject_t -> {snapid}
+ *  2) snapid -> {hobject_t}
+ *
+ * We accomplish this using two sets of keys:
+ *  1) OBJECT_PREFIX + obj.str() -> encoding of object_snaps
+ *  2) MAPPING_PREFIX + snapid_t + obj.str() -> encoding of pair<snapid_t, obj>
+ *
+ * The on disk strings and encodings are implemented in to_raw, to_raw_key,
+ * from_raw, to_object_key.
+ *
+ * The object -> {snapid} mapping is primarily included so that the
+ * SnapMapper state can be verified against the external PG state during
+ * scrub etc.
+ *
+ * The 2) mapping is arranged such that all objects in a particular
+ * snap will sort together, and so that all objects in a pg for a
+ * particular snap will group under up to 8 prefixes.
+ */
+class SnapMapper {
+public:
+  CephContext* cct;
+  struct object_snaps {
+    hobject_t oid;
+    std::set<snapid_t> snaps;
+    object_snaps(hobject_t oid, const std::set<snapid_t> &snaps)
+      : oid(oid), snaps(snaps) {}
+    object_snaps() {}
+    void encode(bufferlist &bl) const;
+    void decode(bufferlist::const_iterator &bp);
+  };
+
+private:
+  MapCacher::MapCacher<std::string, bufferlist> backend;
+
+  static const std::string MAPPING_PREFIX;
+  static const std::string OBJECT_PREFIX;
+
+  static std::string get_prefix(snapid_t snap);
+
+  std::string to_raw_key(
+    const std::pair<snapid_t, hobject_t> &to_map);
+
+  std::pair<std::string, bufferlist> to_raw(
+    const std::pair<snapid_t, hobject_t> &to_map);
+
+  static bool is_mapping(const std::string &to_test);
+
+  std::pair<snapid_t, hobject_t> from_raw(
+    const std::pair<std::string, bufferlist> &image);
+
+  std::string to_object_key(const hobject_t &hoid);
+
+  int get_snaps(const hobject_t &oid, object_snaps *out);
+
+  void set_snaps(
+    const hobject_t &oid,
+    const object_snaps &out,
+    MapCacher::Transaction<std::string, bufferlist> *t);
+
+  void clear_snaps(
+    const hobject_t &oid,
+    MapCacher::Transaction<std::string, bufferlist> *t);
+
+  // True if hoid belongs in this mapping based on mask_bits and match
+  bool check(const hobject_t &hoid) const;
+
+  int _remove_oid(
+    const hobject_t &oid,    ///< [in] oid to remove
+    MapCacher::Transaction<std::string, bufferlist> *t ///< [out] transaction
+    );
+
+public:
+  static string make_shard_prefix(shard_id_t shard) {
+    if (shard == shard_id_t::NO_SHARD)
+      return string();
+    char buf[20];
+    int r = snprintf(buf, sizeof(buf), ".%x", (int)shard);
+    ceph_assert(r < (int)sizeof(buf));
+    return string(buf, r) + '_';
+  }
+  uint32_t mask_bits;
+  const uint32_t match;
+  string last_key_checked;
+  const int64_t pool;
+  const shard_id_t shard;
+  const string shard_prefix;
+  SnapMapper(
+    CephContext* cct,
+    MapCacher::StoreDriver<std::string, bufferlist> *driver,
+    uint32_t match,  ///< [in] pgid
+    uint32_t bits,   ///< [in] current split bits
+    int64_t pool,    ///< [in] pool
+    shard_id_t shard ///< [in] shard
+    )
+    : cct(cct), backend(driver), mask_bits(bits), match(match), pool(pool),
+      shard(shard), shard_prefix(make_shard_prefix(shard)) {
+    update_bits(mask_bits);
+  }
+
+  set<string> prefixes;
+  /// Update bits in case of pg split or merge
+  void update_bits(
+    uint32_t new_bits  ///< [in] new split bits
+    ) {
+    mask_bits = new_bits;
+    set<string> _prefixes = hobject_t::get_prefixes(
+      mask_bits,
+      match,
+      pool);
+    prefixes.clear();
+    for (set<string>::iterator i = _prefixes.begin();
+	 i != _prefixes.end();
+	 ++i) {
+      prefixes.insert(shard_prefix + *i);
+    }
+  }
+
+  /// Update snaps for oid, empty new_snaps removes the mapping
+  int update_snaps(
+    const hobject_t &oid,       ///< [in] oid to update
+    const std::set<snapid_t> &new_snaps, ///< [in] new snap set
+    const std::set<snapid_t> *old_snaps, ///< [in] old snaps (for debugging)
+    MapCacher::Transaction<std::string, bufferlist> *t ///< [out] transaction
+    ); ///@ return error, 0 on success
+
+  /// Add mapping for oid, must not already be mapped
+  void add_oid(
+    const hobject_t &oid,       ///< [in] oid to add
+    const std::set<snapid_t>& new_snaps, ///< [in] snaps
+    MapCacher::Transaction<std::string, bufferlist> *t ///< [out] transaction
+    );
+
+  /// Returns first object with snap as a snap
+  int get_next_objects_to_trim(
+    snapid_t snap,              ///< [in] snap to check
+    unsigned max,               ///< [in] max to get
+    vector<hobject_t> *out      ///< [out] next objects to trim (must be empty)
+    );  ///< @return error, -ENOENT if no more objects
+
+  /// Remove mapping for oid
+  int remove_oid(
+    const hobject_t &oid,    ///< [in] oid to remove
+    MapCacher::Transaction<std::string, bufferlist> *t ///< [out] transaction
+    ); ///< @return error, -ENOENT if the object is not mapped
+
+  /// Get snaps for oid
+  int get_snaps(
+    const hobject_t &oid,     ///< [in] oid to get snaps for
+    std::set<snapid_t> *snaps ///< [out] snaps
+    ); ///< @return error, -ENOENT if oid is not recorded
+};
+WRITE_CLASS_ENCODER(SnapMapper::object_snaps)
+
+#endif