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-rw-r--r--src/mds/inode_backtrace.h97
1 files changed, 97 insertions, 0 deletions
diff --git a/src/mds/inode_backtrace.h b/src/mds/inode_backtrace.h
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+++ b/src/mds/inode_backtrace.h
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+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+#ifndef CEPH_INODE_BACKTRACE_H
+#define CEPH_INODE_BACKTRACE_H
+
+#include <string_view>
+
+#include "mdstypes.h"
+
+namespace ceph {
+ class Formatter;
+}
+
+/** metadata backpointers **/
+
+/*
+ * - inode_backpointer_t is just the _pointer_ portion; it doesn't
+ * tell us who we point _from_.
+ *
+ * - it _does_ include a version of the source object, so we can look
+ * at two different pointers (from the same inode) and tell which is
+ * newer.
+ */
+struct inode_backpointer_t {
+ inodeno_t dirino; // containing directory ino
+ string dname; // linking dentry name
+ version_t version; // child's version at time of backpointer creation
+
+ inode_backpointer_t() : version(0) {}
+ inode_backpointer_t(inodeno_t i, std::string_view d, version_t v) : dirino(i), dname(d), version(v) {}
+
+ void encode(bufferlist& bl) const;
+ void decode(bufferlist::const_iterator &bl);
+ void decode_old(bufferlist::const_iterator &bl);
+ void dump(Formatter *f) const;
+ static void generate_test_instances(list<inode_backpointer_t*>& ls);
+};
+WRITE_CLASS_ENCODER(inode_backpointer_t)
+
+inline bool operator==(const inode_backpointer_t& l, const inode_backpointer_t& r) {
+ return l.dirino == r.dirino && l.version == r.version && l.dname == r.dname;
+}
+
+inline ostream& operator<<(ostream& out, const inode_backpointer_t& ib) {
+ return out << "<" << ib.dirino << "/" << ib.dname << " v" << ib.version << ">";
+}
+
+/*
+ * inode_backtrace_t is a complete ancestor backtraces for a given inode.
+ * we include who _we_ are, so that the backtrace can stand alone (as, say,
+ * an xattr on an object).
+ */
+struct inode_backtrace_t {
+ inodeno_t ino; // my ino
+ vector<inode_backpointer_t> ancestors;
+ int64_t pool;
+ // we use a set for old_pools to avoid duplicate entries, e.g. setlayout 0, 1, 0
+ set<int64_t> old_pools;
+
+ inode_backtrace_t() : pool(-1) {}
+
+ void encode(bufferlist& bl) const;
+ void decode(bufferlist::const_iterator &bl);
+ void dump(Formatter *f) const;
+ static void generate_test_instances(list<inode_backtrace_t*>& ls);
+
+ /**
+ * Compare two backtraces *for the same inode*.
+ * @pre The backtraces are for the same inode
+ *
+ * @param other The backtrace to compare ourselves with
+ * @param equivalent A bool pointer which will be set to true if
+ * the other backtrace is equivalent to our own (has the same dentries)
+ * @param divergent A bool pointer which will be set to true if
+ * the backtraces have differing entries without versions supporting them
+ *
+ * @returns 1 if we are newer than the other, 0 if equal, -1 if older
+ */
+ int compare(const inode_backtrace_t& other,
+ bool *equivalent, bool *divergent) const;
+};
+WRITE_CLASS_ENCODER(inode_backtrace_t)
+
+inline ostream& operator<<(ostream& out, const inode_backtrace_t& it) {
+ return out << "(" << it.pool << ")" << it.ino << ":" << it.ancestors << "//" << it.old_pools;
+}
+
+inline bool operator==(const inode_backtrace_t& l,
+ const inode_backtrace_t& r) {
+ return l.ino == r.ino &&
+ l.pool == r.pool &&
+ l.old_pools == r.old_pools &&
+ l.ancestors == r.ancestors;
+}
+
+#endif
+