+++ /dev/null
-// vim: ts=8 sw=2 smarttab
-/*
- * Ceph - scalable distributed file system
- *
- * Copyright (C) 2015 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 STRAY_MANAGER_H
-#define STRAY_MANAGER_H
-
-#include "include/elist.h"
-#include <list>
-#include "mds/PurgeQueue.h"
-
-class MDSRank;
-class PerfCounters;
-class CInode;
-class CDentry;
-
-class StrayManager
-{
- protected:
- // Has passed through eval_stray and still has refs
- elist<CDentry*> delayed_eval_stray;
-
- // strays that have been trimmed from cache
- std::set<std::string> trimmed_strays;
-
- // Global references for doing I/O
- MDSRank *mds;
- PerfCounters *logger;
-
- bool started;
-
- // Stray dentries for this rank (including those not in cache)
- uint64_t num_strays;
-
- // Stray dentries
- uint64_t num_strays_delayed;
-
- // Entries that have entered enqueue() but not been persistently
- // recorded by PurgeQueue yet
- uint64_t num_strays_enqueuing;
-
- PurgeQueue &purge_queue;
-
- void truncate(CDentry *dn);
-
- /**
- * Purge a dentry from a stray directory. This function
- * is called once eval_stray is satisfied and StrayManager
- * throttling is also satisfied. There is no going back
- * at this stage!
- */
- void purge(CDentry *dn);
-
- /**
- * Completion handler for a Filer::purge on a stray inode.
- */
- void _purge_stray_purged(CDentry *dn, bool only_head);
-
- void _purge_stray_logged(CDentry *dn, version_t pdv, LogSegment *ls);
-
- /**
- * Callback: we have logged the update to an inode's metadata
- * reflecting it's newly-zeroed length.
- */
- void _truncate_stray_logged(CDentry *dn, LogSegment *ls);
-
- friend class StrayManagerIOContext;
- friend class StrayManagerLogContext;
- friend class StrayManagerContext;
-
- friend class C_StraysFetched;
- friend class C_OpenSnapParents;
- friend class C_PurgeStrayLogged;
- friend class C_TruncateStrayLogged;
- friend class C_IO_PurgeStrayPurged;
-
-
- // Call this on a dentry that has been identified as
- // elegible for purging. It will be passed on to PurgeQueue.
- void enqueue(CDentry *dn, bool trunc);
-
- // Final part of enqueue() which we may have to retry
- // after opening snap parents.
- void _enqueue(CDentry *dn, bool trunc);
-
-
- /**
- * When hard links exist to an inode whose primary dentry
- * is unlinked, the inode gets a stray primary dentry.
- *
- * We may later "reintegrate" the inode into a remaining
- * non-stray dentry (one of what was previously a remote
- * dentry) by issuing a rename from the stray to the other
- * dentry.
- */
- void reintegrate_stray(CDentry *dn, CDentry *rlink);
-
- /**
- * Evaluate a stray dentry for purging or reintegration.
- *
- * purging: If the inode has no linkage, and no more references, then
- * we may decide to purge it.
- *
- * reintegration: If the inode still has linkage, then it means someone else
- * (a hard link) is still referring to it, and we should
- * think about reintegrating that inode into the remote dentry.
- *
- * @returns true if the dentry will be purged (caller should never
- * take more refs after this happens), else false.
- */
- bool _eval_stray(CDentry *dn, bool delay=false);
-
- void _eval_stray_remote(CDentry *stray_dn, CDentry *remote_dn);
-
- // My public interface is for consumption by MDCache
- public:
- explicit StrayManager(MDSRank *mds, PurgeQueue &purge_queue_);
- void set_logger(PerfCounters *l) {logger = l;}
- void activate();
-
- bool eval_stray(CDentry *dn, bool delay=false);
-
- void set_num_strays(uint64_t num);
- uint64_t get_num_strays() const { return num_strays; }
-
- /**
- * Where eval_stray was previously invoked with delay=true, call
- * eval_stray again for any dentries that were put on the
- * delayed_eval_stray list as a result of the original call.
- *
- * Used so that various places can call eval_stray(delay=true) during
- * an operation to identify dentries of interest, and then call
- * this function later during trim in order to do the final
- * evaluation (and resulting actions) while not in the middle of another
- * metadata operation.
- */
- void advance_delayed();
-
- /**
- * Remote dentry potentially points to a stray. When it is touched,
- * call in here to evaluate it for migration (move a stray residing
- * on another MDS to this MDS) or reintegration (move a stray dentry's
- * inode into a non-stray hardlink dentry and clean up the stray).
- *
- * @param stray_dn a stray dentry whose inode has been referenced
- * by a remote dentry
- * @param remote_dn (optional) which remote dentry was touched
- * in an operation that led us here: this is used
- * as a hint for which remote to reintegrate into
- * if there are multiple remotes.
- */
- void eval_remote(CDentry *remote_dn);
-
- /**
- * Given a dentry within one of my stray directories,
- * send it off to a stray directory in another MDS.
- *
- * This is for use:
- * * Case A: when shutting down a rank, we migrate strays
- * away from ourselves rather than waiting for purge
- * * Case B: when a client request has a trace that refers to
- * a stray inode on another MDS, we migrate that inode from
- * there to here, in order that we can later re-integrate it
- * here.
- *
- * In case B, the receiver should be calling into eval_stray
- * on completion of mv (i.e. inode put), resulting in a subsequent
- * reintegration.
- */
- void migrate_stray(CDentry *dn, mds_rank_t dest);
-
- /**
- * Update stats to reflect a newly created stray dentry. Needed
- * because stats on strays live here, but creation happens
- * in Server or MDCache. For our purposes "creation" includes
- * loading a stray from a dirfrag and migrating a stray from
- * another MDS, in addition to creations per-se.
- */
- void notify_stray_created();
-
- /**
- * Update stats to reflect a removed stray dentry. Needed because
- * stats on strays live here, but removal happens in Server or
- * MDCache. Also includes migration (rename) of strays from
- * this MDS to another MDS.
- */
- void notify_stray_removed();
-};
-
-#endif // STRAY_MANAGER_H
Code Review / stor4nfv.git / blobdiff