X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=src%2Fceph%2Fsrc%2Fosd%2FPGTransaction.h;fp=src%2Fceph%2Fsrc%2Fosd%2FPGTransaction.h;h=a77a9dae78fb19cff64415a15fc7ed27ac0e56ff;hb=812ff6ca9fcd3e629e49d4328905f33eee8ca3f5;hp=0000000000000000000000000000000000000000;hpb=15280273faafb77777eab341909a3f495cf248d9;p=stor4nfv.git

diff --git a/src/ceph/src/osd/PGTransaction.h b/src/ceph/src/osd/PGTransaction.h
new file mode 100644
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+++ b/src/ceph/src/osd/PGTransaction.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) 2016 Red Hat
+ *
+ * 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 PGTRANSACTION_H
+#define PGTRANSACTION_H
+
+#include <map>
+#include <memory>
+#include <boost/optional.hpp>
+
+#include "common/hobject.h"
+#include "osd/osd_types.h"
+#include "osd/osd_internal_types.h"
+#include "common/interval_map.h"
+#include "common/inline_variant.h"
+
+/**
+ * This class represents transactions which can be submitted to
+ * a PGBackend.  For expediency, there are some constraints on
+ * the operations submitted:
+ * 1) Rename sources may only be referenced prior to the rename
+ *    operation to the destination.
+ * 2) The graph formed by edges of source->destination for clones
+ *    (Create) and Renames must be acyclic.
+ * 3) clone_range sources must not be modified by the same
+ *    transaction
+ */
+class PGTransaction {
+public:
+  map<hobject_t, ObjectContextRef> obc_map;
+
+  class ObjectOperation {
+  public:
+    struct Init
+    {
+      struct None {};
+      struct Create {};
+      struct Clone {
+	hobject_t source;
+      };
+      struct Rename {
+	hobject_t source; // must be temp object
+      };
+    };
+    using InitType = boost::variant<
+      Init::None,
+      Init::Create,
+      Init::Clone,
+      Init::Rename>;
+
+    InitType init_type = Init::None();
+    bool delete_first = false;
+
+    /**
+     * is_none() && is_delete() indicates that we are deleting an
+     * object which already exists and not recreating it. delete_first means
+     * that the transaction logically removes the object.
+
+     * There are really 4 cases:
+
+     * 1) We are modifying an existing object (is_none() &&
+     *    !is_delete())
+     *    a) If it's an append, we just write into the log entry the old size
+     *    b) If it's an actual overwrite, we save the old versions of the
+     *       extents being overwritten and write those offsets into the log
+     *       entry
+     * 2) We are removing and then recreating an object (!is_none() && is_delete())
+     *    -- stash
+     * 3) We are removing an object (is_none() && is_delete()) -- stash
+     * 4) We are creating an object (!is_none() && !is_delete()) -- create (no
+     *    stash)
+     *
+     * Create, Clone, Rename are the three ways we can recreate it.
+     * ECBackend transaction planning needs this context
+     * to figure out how to perform the transaction.
+     */
+    bool deletes_first() const {
+      return delete_first;
+    }
+    bool is_delete() const {
+      return boost::get<Init::None>(&init_type) != nullptr && delete_first;
+    }
+    bool is_none() const {
+      return boost::get<Init::None>(&init_type) != nullptr && !delete_first;
+    }
+    bool is_fresh_object() const {
+      return boost::get<Init::None>(&init_type) == nullptr;
+    }
+    bool is_rename() const {
+      return boost::get<Init::Rename>(&init_type) != nullptr;
+    }
+    bool has_source(hobject_t *source = nullptr) const {
+      return match(
+	init_type,
+	[&](const Init::Clone &op) -> bool {
+	  if (source)
+	    *source = op.source;
+	  return true;
+	},
+	[&](const Init::Rename &op) -> bool {
+	  if (source)
+	    *source = op.source;
+	  return true;
+	},
+	[&](const Init::None &) -> bool { return false; },
+	[&](const Init::Create &) -> bool { return false; });
+    }
+
+    bool clear_omap = false;
+
+    /**
+     * truncate
+     * <lowest, last> ?
+     *
+     * truncate is represented as a pair because in the event of
+     * multiple truncates within a single transaction we need to
+     * remember the lowest truncate and the final object size
+     * (the last truncate).  We also adjust the buffers map
+     * to account for truncates overriding previous writes */
+    boost::optional<pair<uint64_t, uint64_t> > truncate = boost::none;
+
+    std::map<string, boost::optional<bufferlist> > attr_updates;
+
+    enum class OmapUpdateType {Remove, Insert};
+    std::vector<std::pair<OmapUpdateType, bufferlist> > omap_updates;
+
+    boost::optional<bufferlist> omap_header;
+
+    /// (old, new) -- only valid with no truncate or buffer updates
+    boost::optional<pair<set<snapid_t>, set<snapid_t> > > updated_snaps;
+
+    struct alloc_hint_t {
+      uint64_t expected_object_size;
+      uint64_t expected_write_size;
+      uint32_t flags;
+    };
+    boost::optional<alloc_hint_t> alloc_hint;
+
+    struct BufferUpdate {
+      struct Write {
+	bufferlist buffer;
+	uint32_t fadvise_flags;
+      };
+      struct Zero {
+	uint64_t len;
+      };
+      struct CloneRange {
+	hobject_t from;
+	uint64_t offset;
+	uint64_t len;
+      };
+    };
+    using BufferUpdateType = boost::variant<
+      BufferUpdate::Write,
+      BufferUpdate::Zero,
+      BufferUpdate::CloneRange>;
+
+  private:
+    struct SplitMerger {
+      BufferUpdateType split(
+	uint64_t offset,
+	uint64_t len,
+	const BufferUpdateType &bu) const {
+	return match(
+	  bu,
+	  [&](const BufferUpdate::Write &w) -> BufferUpdateType {
+	    bufferlist bl;
+	    bl.substr_of(w.buffer, offset, len);
+	    return BufferUpdate::Write{bl, w.fadvise_flags};
+	  },
+	  [&](const BufferUpdate::Zero &) -> BufferUpdateType {
+	    return BufferUpdate::Zero{len};
+	  },
+	  [&](const BufferUpdate::CloneRange &c) -> BufferUpdateType {
+	    return BufferUpdate::CloneRange{c.from, c.offset + offset, len};
+	  });
+      }
+      uint64_t length(
+	const BufferUpdateType &left) const {
+	return match(
+	  left,
+	  [&](const BufferUpdate::Write &w) -> uint64_t {
+	    return w.buffer.length();
+	  },
+	  [&](const BufferUpdate::Zero &z) -> uint64_t {
+	    return z.len;
+	  },
+	  [&](const BufferUpdate::CloneRange &c) -> uint64_t {
+	    return c.len;
+	  });
+      }
+      bool can_merge(
+	const BufferUpdateType &left,
+	const BufferUpdateType &right) const {
+	return match(
+	  left,
+	  [&](const BufferUpdate::Write &w) -> bool {
+	    auto r = boost::get<BufferUpdate::Write>(&right);
+	    return r != nullptr && (w.fadvise_flags == r->fadvise_flags);
+	  },
+	  [&](const BufferUpdate::Zero &) -> bool {
+	    auto r = boost::get<BufferUpdate::Zero>(&right);
+	    return r != nullptr;
+	  },
+	  [&](const BufferUpdate::CloneRange &c) -> bool {
+	    return false;
+	  });
+      }
+      BufferUpdateType merge(
+	BufferUpdateType &&left,
+	BufferUpdateType &&right) const {
+	return match(
+	  left,
+	  [&](const BufferUpdate::Write &w) -> BufferUpdateType {
+	    auto r = boost::get<BufferUpdate::Write>(&right);
+	    assert(r && w.fadvise_flags == r->fadvise_flags);
+	    bufferlist bl = w.buffer;
+	    bl.append(r->buffer);
+	    return BufferUpdate::Write{bl, w.fadvise_flags};
+	  },
+	  [&](const BufferUpdate::Zero &z) -> BufferUpdateType {
+	    auto r = boost::get<BufferUpdate::Zero>(&right);
+	    assert(r);
+	    return BufferUpdate::Zero{z.len + r->len};
+	  },
+	  [&](const BufferUpdate::CloneRange &c) -> BufferUpdateType {
+	    assert(0 == "violates can_merge condition");
+	    return left;
+	  });
+      }
+    };
+  public:
+    using buffer_update_type = interval_map<
+      uint64_t, BufferUpdateType, SplitMerger>;
+    buffer_update_type buffer_updates;
+
+    friend class PGTransaction;
+  };
+  map<hobject_t, ObjectOperation> op_map;
+private:
+  ObjectOperation &get_object_op_for_modify(const hobject_t &hoid) {
+    auto &op = op_map[hoid];
+    assert(!op.is_delete());
+    return op;
+  }
+  ObjectOperation &get_object_op(const hobject_t &hoid) {
+    return op_map[hoid];
+  }
+public:
+  void add_obc(
+    ObjectContextRef obc) {
+    assert(obc);
+    obc_map[obc->obs.oi.soid] = obc;
+  }
+  /// Sets up state for new object
+  void create(
+    const hobject_t &hoid
+    ) {
+    auto &op = op_map[hoid];
+    assert(op.is_none() || op.is_delete());
+    op.init_type = ObjectOperation::Init::Create();
+  }
+
+  /// Sets up state for target cloned from source
+  void clone(
+    const hobject_t &target,       ///< [in] obj to clone to
+    const hobject_t &source        ///< [in] obj to clone from
+    ) {
+    auto &op = op_map[target];
+    assert(op.is_none() || op.is_delete());
+    op.init_type = ObjectOperation::Init::Clone{source};
+  }
+
+  /// Sets up state for target renamed from source
+  void rename(
+    const hobject_t &target,       ///< [in] source (must be a temp object)
+    const hobject_t &source        ///< [in] to, must not exist, be non-temp
+    ) {
+    assert(source.is_temp());
+    assert(!target.is_temp());
+    auto &op = op_map[target];
+    assert(op.is_none() || op.is_delete());
+
+    bool del_first = op.is_delete();
+    auto iter = op_map.find(source);
+    if (iter != op_map.end()) {
+      op = iter->second;
+      op_map.erase(iter);
+      op.delete_first = del_first;
+    }
+
+    op.init_type = ObjectOperation::Init::Rename{source};
+  }
+
+  /// Remove -- must not be called on rename target
+  void remove(
+    const hobject_t &hoid          ///< [in] obj to remove
+    ) {
+    auto &op = get_object_op_for_modify(hoid);
+    if (!op.is_fresh_object()) {
+      assert(!op.updated_snaps);
+      op = ObjectOperation();
+      op.delete_first = true;
+    } else {
+      assert(!op.is_rename());
+      op_map.erase(hoid); // make it a noop if it's a fresh object
+    }
+  }
+
+  void update_snaps(
+    const hobject_t &hoid,         ///< [in] object for snaps
+    const set<snapid_t> &old_snaps,///< [in] old snaps value
+    const set<snapid_t> &new_snaps ///< [in] new snaps value
+    ) {
+    auto &op = get_object_op(hoid);
+    assert(!op.updated_snaps);
+    assert(op.buffer_updates.empty());
+    assert(!op.truncate);
+    op.updated_snaps = make_pair(
+      old_snaps,
+      new_snaps);
+  }
+
+  /// Clears, truncates
+  void omap_clear(
+    const hobject_t &hoid          ///< [in] object to clear omap
+    ) {
+    auto &op = get_object_op_for_modify(hoid);
+    op.clear_omap = true;
+    op.omap_updates.clear();
+    op.omap_header = boost::none;
+  }
+  void truncate(
+    const hobject_t &hoid,         ///< [in] object
+    uint64_t off                   ///< [in] offset to truncate to
+    ) {
+    auto &op = get_object_op_for_modify(hoid);
+    assert(!op.updated_snaps);
+    op.buffer_updates.erase(
+      off,
+      std::numeric_limits<uint64_t>::max() - off);
+    if (!op.truncate || off < op.truncate->first) {
+      op.truncate = std::pair<uint64_t, uint64_t>(off, off);
+    } else {
+      op.truncate->second = off;
+    }
+  }
+
+  /// Attr ops
+  void setattrs(
+    const hobject_t &hoid,         ///< [in] object to write
+    map<string, bufferlist> &attrs ///< [in] attrs, may be cleared
+    ) {
+    auto &op = get_object_op_for_modify(hoid);
+    for (auto &&i: attrs) {
+      op.attr_updates[i.first] = i.second;
+    }
+  }
+  void setattr(
+    const hobject_t &hoid,         ///< [in] object to write
+    const string &attrname,        ///< [in] attr to write
+    bufferlist &bl                 ///< [in] val to write, may be claimed
+    ) {
+    auto &op = get_object_op_for_modify(hoid);
+    op.attr_updates[attrname] = bl;
+  }
+  void rmattr(
+    const hobject_t &hoid,         ///< [in] object to write
+    const string &attrname         ///< [in] attr to remove
+    ) {
+    auto &op = get_object_op_for_modify(hoid);
+    op.attr_updates[attrname] = boost::none;
+  }
+
+  /// set alloc hint
+  void set_alloc_hint(
+    const hobject_t &hoid,         ///< [in] object (must exist)
+    uint64_t expected_object_size, ///< [in]
+    uint64_t expected_write_size,
+    uint32_t flags
+    ) {
+    auto &op = get_object_op_for_modify(hoid);
+    op.alloc_hint = ObjectOperation::alloc_hint_t{
+      expected_object_size, expected_write_size, flags};
+  }
+
+  /// Buffer updates
+  void write(
+    const hobject_t &hoid,         ///< [in] object to write
+    uint64_t off,                  ///< [in] off at which to write
+    uint64_t len,                  ///< [in] len to write from bl
+    bufferlist &bl,                ///< [in] bl to write will be claimed to len
+    uint32_t fadvise_flags = 0     ///< [in] fadvise hint
+    ) {
+    auto &op = get_object_op_for_modify(hoid);
+    assert(!op.updated_snaps);
+    assert(len > 0);
+    assert(len == bl.length());
+    op.buffer_updates.insert(
+      off,
+      len,
+      ObjectOperation::BufferUpdate::Write{bl, fadvise_flags});
+  }
+  void clone_range(
+    const hobject_t &from,         ///< [in] from
+    const hobject_t &to,           ///< [in] to
+    uint64_t fromoff,              ///< [in] offset
+    uint64_t len,                  ///< [in] len
+    uint64_t tooff                 ///< [in] offset
+    ) {
+    auto &op = get_object_op_for_modify(to);
+    assert(!op.updated_snaps);
+    op.buffer_updates.insert(
+      tooff,
+      len,
+      ObjectOperation::BufferUpdate::CloneRange{from, fromoff, len});
+  }
+  void zero(
+    const hobject_t &hoid,         ///< [in] object
+    uint64_t off,                  ///< [in] offset to start zeroing at
+    uint64_t len                   ///< [in] amount to zero
+    ) {
+    auto &op = get_object_op_for_modify(hoid);
+    assert(!op.updated_snaps);
+    op.buffer_updates.insert(
+      off,
+      len,
+      ObjectOperation::BufferUpdate::Zero{len});
+  }
+
+  /// Omap updates
+  void omap_setkeys(
+    const hobject_t &hoid,         ///< [in] object to write
+    bufferlist &keys_bl            ///< [in] encoded map<string, bufferlist>
+    ) {
+    auto &op = get_object_op_for_modify(hoid);
+    op.omap_updates.emplace_back(
+      make_pair(
+	ObjectOperation::OmapUpdateType::Insert,
+	keys_bl));
+  }
+  void omap_setkeys(
+    const hobject_t &hoid,         ///< [in] object to write
+    map<string, bufferlist> &keys  ///< [in] omap keys, may be cleared
+    ) {
+    bufferlist bl;
+    ::encode(keys, bl);
+    omap_setkeys(hoid, bl);
+  }
+  void omap_rmkeys(
+    const hobject_t &hoid,         ///< [in] object to write
+    bufferlist &keys_bl            ///< [in] encode set<string>
+    ) {
+    auto &op = get_object_op_for_modify(hoid);
+    op.omap_updates.emplace_back(
+      make_pair(
+	ObjectOperation::OmapUpdateType::Remove,
+	keys_bl));
+  }
+  void omap_rmkeys(
+    const hobject_t &hoid,         ///< [in] object to write
+    set<string> &keys              ///< [in] omap keys, may be cleared
+    ) {
+    bufferlist bl;
+    ::encode(keys, bl);
+    omap_rmkeys(hoid, bl);
+  }
+  void omap_setheader(
+    const hobject_t &hoid,         ///< [in] object to write
+    bufferlist &header             ///< [in] header
+    ) {
+    auto &op = get_object_op_for_modify(hoid);
+    op.omap_header = header;
+  }
+
+  bool empty() const {
+    return op_map.empty();
+  }
+
+  uint64_t get_bytes_written() const {
+    uint64_t ret = 0;
+    for (auto &&i: op_map) {
+      for (auto &&j: i.second.buffer_updates) {
+	ret += j.get_len();
+      }
+    }
+    return ret;
+  }
+
+  void nop(
+    const hobject_t &hoid ///< [in] obj to which we are doing nothing
+    ) {
+    get_object_op_for_modify(hoid);
+  }
+
+  /* Calls t() on all pair<hobject_t, ObjectOperation> & such that clone/rename
+   * sinks are always called before clone sources
+   *
+   * TODO: add a fast path for the single object case and possibly the single
+   * object clone from source case (make_writeable made a clone).
+   *
+   * This structure only requires that the source->sink graph be acyclic.
+   * This is much more general than is actually required by PrimaryLogPG.
+   * Only 4 flavors of multi-object transactions actually happen:
+   * 1) rename temp -> object for copyfrom
+   * 2) clone head -> clone, modify head for make_writeable on normal head write
+   * 3) clone clone -> head for rollback
+   * 4) 2 + 3
+   *
+   * We can bypass the below logic for single object transactions trivially
+   * (including case 1 above since temp doesn't show up again).
+   * For 2-3, we could add something ad-hoc to ensure that they happen in the
+   * right order, but it actually seems easier to just do the graph construction.
+   */
+  template <typename T>
+  void safe_create_traverse(T &&t) {
+    map<hobject_t, list<hobject_t>> dgraph;
+    list<hobject_t> stack;
+
+    // Populate stack with roots, dgraph with edges
+    for (auto &&opair: op_map) {
+      hobject_t source;
+      if (opair.second.has_source(&source)) {
+	auto &l = dgraph[source];
+	if (l.empty() && !op_map.count(source)) {
+	  /* Source oids not in op_map need to be added as roots
+	   * (but only once!) */
+	  stack.push_back(source);
+	}
+	l.push_back(opair.first);
+      } else {
+	stack.push_back(opair.first);
+      }
+    }
+
+    /* Why don't we need to worry about accessing the same node
+     * twice?  dgraph nodes always have in-degree at most 1 because
+     * the inverse graph nodes (source->dest) can have out-degree
+     * at most 1 (only one possible source).  We do a post-order
+     * depth-first traversal here to ensure we call f on children
+     * before parents.
+     */
+    while (!stack.empty()) {
+      hobject_t &cur = stack.front();
+      auto diter = dgraph.find(cur);
+      if (diter == dgraph.end()) {
+	/* Leaf: pop and call t() */
+	auto opiter = op_map.find(cur);
+	if (opiter != op_map.end())
+	  t(*opiter);
+	stack.pop_front();
+      } else {
+	/* Internal node: push children onto stack, remove edge,
+	 * recurse.  When this node is encountered again, it'll
+	 * be a leaf */
+	assert(!diter->second.empty());
+	stack.splice(stack.begin(), diter->second);
+	dgraph.erase(diter);
+      }
+    }
+  }
+};
+using PGTransactionUPtr = std::unique_ptr<PGTransaction>;
+
+#endif