ceph/src/mds/StrayManager.cc

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3 /*
   4  * Ceph - scalable distributed file system
   5  *
   6  * Copyright (C) 2015 Red Hat
   7  *
   8  * This is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License version 2.1, as published by the Free Software
  11  * Foundation.  See file COPYING.
  12  *
  13  */
  14
  15
  16 #include "common/perf_counters.h"
  17
  18 #include "mds/MDSRank.h"
  19 #include "mds/MDCache.h"
  20 #include "mds/MDLog.h"
  21 #include "mds/CDir.h"
  22 #include "mds/CDentry.h"
  23 #include "events/EUpdate.h"
  24 #include "messages/MClientRequest.h"
  25
  26 #include "StrayManager.h"
  27
  28 #define dout_context g_ceph_context
  29 #define dout_subsys ceph_subsys_mds
  30 #undef dout_prefix
  31 #define dout_prefix _prefix(_dout, mds)
  32 static ostream& _prefix(std::ostream *_dout, MDSRank *mds) {
  33   return *_dout << "mds." << mds->get_nodeid() << ".cache.strays ";
  34 }
  35
  36 class StrayManagerIOContext : public virtual MDSIOContextBase {
  37 protected:
  38   StrayManager *sm;
  39   MDSRank *get_mds() override
  40   {
  41     return sm->mds;
  42   }
  43 public:
  44   explicit StrayManagerIOContext(StrayManager *sm_) : sm(sm_) {}
  45 };
  46
  47 class StrayManagerLogContext : public virtual MDSLogContextBase {
  48 protected:
  49   StrayManager *sm;
  50   MDSRank *get_mds() override
  51   {
  52     return sm->mds;
  53   }
  54 public:
  55   explicit StrayManagerLogContext(StrayManager *sm_) : sm(sm_) {}
  56 };
  57
  58 class StrayManagerContext : public virtual MDSInternalContextBase {
  59 protected:
  60   StrayManager *sm;
  61   MDSRank *get_mds() override
  62   {
  63     return sm->mds;
  64   }
  65 public:
  66   explicit StrayManagerContext(StrayManager *sm_) : sm(sm_) {}
  67 };
  68
  69
  70 /**
  71  * Context wrapper for _purge_stray_purged completion
  72  */
  73 class C_IO_PurgeStrayPurged : public StrayManagerIOContext {
  74   CDentry *dn;
  75   bool only_head;
  76 public:
  77   C_IO_PurgeStrayPurged(StrayManager *sm_, CDentry *d, bool oh) :
  78     StrayManagerIOContext(sm_), dn(d), only_head(oh) { }
  79   void finish(int r) override {
  80     assert(r == 0 || r == -ENOENT);
  81     sm->_purge_stray_purged(dn, only_head);
  82   }
  83 };
  84
  85
  86 void StrayManager::purge(CDentry *dn)
  87 {
  88   CDentry::linkage_t *dnl = dn->get_projected_linkage();
  89   CInode *in = dnl->get_inode();
  90   dout(10) << __func__ << " " << *dn << " " << *in << dendl;
  91   assert(!dn->is_replicated());
  92
  93   // CHEAT.  there's no real need to journal our intent to purge, since
  94   // that is implicit in the dentry's presence and non-use in the stray
  95   // dir.  on recovery, we'll need to re-eval all strays anyway.
  96
  97   SnapContext nullsnapc;
  98
  99   PurgeItem item;
 100   item.ino = in->inode.ino;
 101   if (in->is_dir()) {
 102     item.action = PurgeItem::PURGE_DIR;
 103     item.fragtree = in->dirfragtree;
 104   } else {
 105     item.action = PurgeItem::PURGE_FILE;
 106
 107     const SnapContext *snapc;
 108     SnapRealm *realm = in->find_snaprealm();
 109     if (realm) {
 110       dout(10) << " realm " << *realm << dendl;
 111       snapc = &realm->get_snap_context();
 112     } else {
 113       dout(10) << " NO realm, using null context" << dendl;
 114       snapc = &nullsnapc;
 115       assert(in->last == CEPH_NOSNAP);
 116     }
 117
 118     uint64_t to = 0;
 119     if (in->is_file()) {
 120       to = in->inode.get_max_size();
 121       to = MAX(in->inode.size, to);
 122       // when truncating a file, the filer does not delete stripe objects that are
 123       // truncated to zero. so we need to purge stripe objects up to the max size
 124       // the file has ever been.
 125       to = MAX(in->inode.max_size_ever, to);
 126     }
 127
 128     inode_t *pi = in->get_projected_inode();
 129
 130     item.size = to;
 131     item.layout = pi->layout;
 132     item.old_pools = pi->old_pools;
 133     item.snapc = *snapc;
 134   }
 135
 136   purge_queue.push(item, new C_IO_PurgeStrayPurged(
 137         this, dn, false));
 138 }
 139
 140 class C_PurgeStrayLogged : public StrayManagerLogContext {
 141   CDentry *dn;
 142   version_t pdv;
 143   LogSegment *ls;
 144 public:
 145   C_PurgeStrayLogged(StrayManager *sm_, CDentry *d, version_t v, LogSegment *s) :
 146     StrayManagerLogContext(sm_), dn(d), pdv(v), ls(s) { }
 147   void finish(int r) override {
 148     sm->_purge_stray_logged(dn, pdv, ls);
 149   }
 150 };
 151
 152 class C_TruncateStrayLogged : public StrayManagerLogContext {
 153   CDentry *dn;
 154   LogSegment *ls;
 155 public:
 156   C_TruncateStrayLogged(StrayManager *sm, CDentry *d, LogSegment *s) :
 157     StrayManagerLogContext(sm), dn(d), ls(s) { }
 158   void finish(int r) override {
 159     sm->_truncate_stray_logged(dn, ls);
 160   }
 161 };
 162
 163 void StrayManager::_purge_stray_purged(
 164     CDentry *dn, bool only_head)
 165 {
 166   CInode *in = dn->get_projected_linkage()->get_inode();
 167   dout(10) << "_purge_stray_purged " << *dn << " " << *in << dendl;
 168
 169   logger->inc(l_mdc_strays_enqueued);
 170   num_strays_enqueuing--;
 171   logger->set(l_mdc_num_strays_enqueuing, num_strays_enqueuing);
 172
 173   if (only_head) {
 174     /* This was a ::truncate */
 175     EUpdate *le = new EUpdate(mds->mdlog, "purge_stray truncate");
 176     mds->mdlog->start_entry(le);
 177
 178     inode_t *pi = in->project_inode();
 179     pi->size = 0;
 180     pi->max_size_ever = 0;
 181     pi->client_ranges.clear();
 182     pi->truncate_size = 0;
 183     pi->truncate_from = 0;
 184     pi->version = in->pre_dirty();
 185
 186     le->metablob.add_dir_context(dn->dir);
 187     le->metablob.add_primary_dentry(dn, in, true);
 188
 189     mds->mdlog->submit_entry(le,
 190         new C_TruncateStrayLogged(
 191           this, dn, mds->mdlog->get_current_segment()));
 192   } else {
 193     if (in->get_num_ref() != (int)in->is_dirty() ||
 194         dn->get_num_ref() != (int)dn->is_dirty() + !!in->get_num_ref() + 1/*PIN_PURGING*/) {
 195       // Nobody should be taking new references to an inode when it
 196       // is being purged (aside from it were
 197
 198       derr << "Rogue reference after purge to " << *dn << dendl;
 199       assert(0 == "rogue reference to purging inode");
 200     }
 201
 202     // kill dentry.
 203     version_t pdv = dn->pre_dirty();
 204     dn->push_projected_linkage(); // NULL
 205
 206     EUpdate *le = new EUpdate(mds->mdlog, "purge_stray");
 207     mds->mdlog->start_entry(le);
 208
 209     // update dirfrag fragstat, rstat
 210     CDir *dir = dn->get_dir();
 211     fnode_t *pf = dir->project_fnode();
 212     pf->version = dir->pre_dirty();
 213     if (in->is_dir())
 214       pf->fragstat.nsubdirs--;
 215     else
 216       pf->fragstat.nfiles--;
 217     pf->rstat.sub(in->inode.accounted_rstat);
 218
 219     le->metablob.add_dir_context(dn->dir);
 220     EMetaBlob::dirlump& dl = le->metablob.add_dir(dn->dir, true);
 221     le->metablob.add_null_dentry(dl, dn, true);
 222     le->metablob.add_destroyed_inode(in->ino());
 223
 224     mds->mdlog->submit_entry(le, new C_PurgeStrayLogged(this, dn, pdv,
 225           mds->mdlog->get_current_segment()));
 226
 227     logger->set(l_mdc_num_strays, num_strays);
 228   }
 229 }
 230
 231 void StrayManager::_purge_stray_logged(CDentry *dn, version_t pdv, LogSegment *ls)
 232 {
 233   CInode *in = dn->get_linkage()->get_inode();
 234   dout(10) << "_purge_stray_logged " << *dn << " " << *in << dendl;
 235
 236   assert(!in->state_test(CInode::STATE_RECOVERING));
 237
 238   bool new_dn = dn->is_new();
 239
 240   // unlink
 241   assert(dn->get_projected_linkage()->is_null());
 242   dn->dir->unlink_inode(dn, !new_dn);
 243   dn->pop_projected_linkage();
 244   dn->mark_dirty(pdv, ls);
 245
 246   dn->dir->pop_and_dirty_projected_fnode(ls);
 247
 248   in->state_clear(CInode::STATE_ORPHAN);
 249   dn->state_clear(CDentry::STATE_PURGING | CDentry::STATE_PURGINGPINNED);
 250   dn->put(CDentry::PIN_PURGING);
 251
 252   // drop dentry?
 253   if (new_dn) {
 254     dout(20) << " dn is new, removing" << dendl;
 255     dn->mark_clean();
 256     dn->dir->remove_dentry(dn);
 257   }
 258
 259   // drop inode
 260   if (in->is_dirty())
 261     in->mark_clean();
 262   in->mdcache->remove_inode(in);
 263 }
 264
 265 void StrayManager::enqueue(CDentry *dn, bool trunc)
 266 {
 267   CDentry::linkage_t *dnl = dn->get_projected_linkage();
 268   assert(dnl);
 269   CInode *in = dnl->get_inode();
 270   assert(in);
 271
 272   /* We consider a stray to be purging as soon as it is enqueued, to avoid
 273    * enqueing it twice */
 274   dn->state_set(CDentry::STATE_PURGING);
 275   in->state_set(CInode::STATE_PURGING);
 276
 277   /* We must clear this as soon as enqueuing it, to prevent the journal
 278    * expiry code from seeing a dirty parent and trying to write a backtrace */
 279   if (!trunc) {
 280     if (in->is_dirty_parent()) {
 281       in->clear_dirty_parent();
 282     }
 283   }
 284
 285   dout(20) << __func__ << ": purging dn: " << *dn << dendl;
 286
 287   if (!dn->state_test(CDentry::STATE_PURGINGPINNED)) {
 288     dn->get(CDentry::PIN_PURGING);
 289     dn->state_set(CDentry::STATE_PURGINGPINNED);
 290   }
 291
 292   ++num_strays_enqueuing;
 293   logger->set(l_mdc_num_strays_enqueuing, num_strays_enqueuing);
 294
 295   // Resources are available, acquire them and execute the purge
 296   _enqueue(dn, trunc);
 297
 298   dout(10) << __func__ << ": purging this dentry immediately: "
 299     << *dn << dendl;
 300 }
 301
 302 class C_OpenSnapParents : public StrayManagerContext {
 303   CDentry *dn;
 304   bool trunc;
 305   public:
 306     C_OpenSnapParents(StrayManager *sm_, CDentry *dn_, bool t) :
 307       StrayManagerContext(sm_), dn(dn_), trunc(t) { }
 308     void finish(int r) override {
 309       sm->_enqueue(dn, trunc);
 310     }
 311 };
 312
 313 void StrayManager::_enqueue(CDentry *dn, bool trunc)
 314 {
 315   assert(started);
 316
 317   CInode *in = dn->get_linkage()->get_inode();
 318   if (in->snaprealm &&
 319       !in->snaprealm->have_past_parents_open() &&
 320       !in->snaprealm->open_parents(new C_OpenSnapParents(this, dn, trunc))) {
 321     // this can happen if the dentry had been trimmed from cache.
 322     return;
 323   }
 324
 325   if (trunc) {
 326     truncate(dn);
 327   } else {
 328     purge(dn);
 329   }
 330 }
 331
 332
 333 void StrayManager::advance_delayed()
 334 {
 335   if (!started)
 336     return;
 337
 338   for (elist<CDentry*>::iterator p = delayed_eval_stray.begin(); !p.end(); ) {
 339     CDentry *dn = *p;
 340     ++p;
 341     dn->item_stray.remove_myself();
 342     num_strays_delayed--;
 343
 344     if (dn->get_projected_linkage()->is_null()) {
 345       /* A special case: a stray dentry can go null if its inode is being
 346        * re-linked into another MDS's stray dir during a shutdown migration. */
 347       dout(4) << __func__ << ": delayed dentry is now null: " << *dn << dendl;
 348       continue;
 349     }
 350
 351     const bool purging = eval_stray(dn);
 352     if (!purging) {
 353       derr << "Dentry " << *dn << " was purgeable but no longer is!" << dendl;
 354       /*
 355        * This can happen if a stray is purgeable, but has gained an extra
 356        * reference by virtue of having its backtrace updated.
 357        * FIXME perhaps we could simplify this further by
 358        * avoiding writing the backtrace of purge-ready strays, so
 359        * that this code could be more rigid?
 360        */
 361     }
 362   }
 363   logger->set(l_mdc_num_strays_delayed, num_strays_delayed);
 364 }
 365
 366 void StrayManager::set_num_strays(uint64_t num)
 367 {
 368   assert(!started);
 369   num_strays = num;
 370   logger->set(l_mdc_num_strays, num_strays);
 371 }
 372
 373 void StrayManager::notify_stray_created()
 374 {
 375   num_strays++;
 376   logger->set(l_mdc_num_strays, num_strays);
 377   logger->inc(l_mdc_strays_created);
 378 }
 379
 380 void StrayManager::notify_stray_removed()
 381 {
 382   num_strays--;
 383   logger->set(l_mdc_num_strays, num_strays);
 384 }
 385
 386 struct C_EvalStray : public StrayManagerContext {
 387   CDentry *dn;
 388   C_EvalStray(StrayManager *sm_, CDentry *d) : StrayManagerContext(sm_), dn(d) {}
 389   void finish(int r) override {
 390     sm->eval_stray(dn);
 391   }
 392 };
 393
 394 struct C_MDC_EvalStray : public StrayManagerContext {
 395   CDentry *dn;
 396   C_MDC_EvalStray(StrayManager *sm_, CDentry *d) : StrayManagerContext(sm_), dn(d) {}
 397   void finish(int r) override {
 398     sm->eval_stray(dn);
 399   }
 400 };
 401
 402 bool StrayManager::_eval_stray(CDentry *dn, bool delay)
 403 {
 404   dout(10) << "eval_stray " << *dn << dendl;
 405   CDentry::linkage_t *dnl = dn->get_projected_linkage();
 406   assert(dnl->is_primary());
 407   dout(10) << " inode is " << *dnl->get_inode() << dendl;
 408   CInode *in = dnl->get_inode();
 409   assert(in);
 410   assert(!in->state_test(CInode::STATE_REJOINUNDEF));
 411
 412   // The only dentries elegible for purging are those
 413   // in the stray directories
 414   assert(dn->get_dir()->get_inode()->is_stray());
 415
 416   // Inode may not pass through this function if it
 417   // was already identified for purging (i.e. cannot
 418   // call eval_stray() after purge()
 419   assert(!dn->state_test(CDentry::STATE_PURGING));
 420
 421   if (!dn->is_auth()) {
 422     return false;
 423   }
 424
 425   if (!started)
 426     delay = true;
 427
 428   if (dn->item_stray.is_on_list()) {
 429     if (delay)
 430       return false;
 431
 432     dn->item_stray.remove_myself();
 433     num_strays_delayed--;
 434     logger->set(l_mdc_num_strays_delayed, num_strays_delayed);
 435   }
 436
 437   // purge?
 438   if (in->inode.nlink == 0) {
 439     // past snaprealm parents imply snapped dentry remote links.
 440     // only important for directories.  normal file data snaps are handled
 441     // by the object store.
 442     if (in->snaprealm) {
 443       if (!in->snaprealm->have_past_parents_open() &&
 444           !in->snaprealm->open_parents(new C_MDC_EvalStray(this, dn))) {
 445         return false;
 446       }
 447       in->snaprealm->prune_past_parents();
 448       in->purge_stale_snap_data(in->snaprealm->get_snaps());
 449     }
 450     if (in->is_dir()) {
 451       if (in->snaprealm && in->snaprealm->has_past_parents()) {
 452         dout(20) << "  directory has past parents "
 453                  << in->snaprealm->srnode.past_parents << dendl;
 454         if (in->state_test(CInode::STATE_MISSINGOBJS)) {
 455           mds->clog->error() << "previous attempt at committing dirfrag of ino "
 456                              << in->ino() << " has failed, missing object";
 457           mds->handle_write_error(-ENOENT);
 458         }
 459         return false;  // not until some snaps are deleted.
 460       }
 461
 462       in->mdcache->clear_dirty_bits_for_stray(in);
 463
 464       if (!in->remote_parents.empty()) {
 465         // unlink any stale remote snap dentry.
 466         for (compact_set<CDentry*>::iterator p = in->remote_parents.begin();
 467              p != in->remote_parents.end(); ) {
 468           CDentry *remote_dn = *p;
 469           ++p;
 470           assert(remote_dn->last != CEPH_NOSNAP);
 471           remote_dn->unlink_remote(remote_dn->get_linkage());
 472         }
 473       }
 474     }
 475     if (dn->is_replicated()) {
 476       dout(20) << " replicated" << dendl;
 477       return false;
 478     }
 479     if (dn->is_any_leases() || in->is_any_caps()) {
 480       dout(20) << " caps | leases" << dendl;
 481       return false;  // wait
 482     }
 483     if (in->state_test(CInode::STATE_NEEDSRECOVER) ||
 484         in->state_test(CInode::STATE_RECOVERING)) {
 485       dout(20) << " pending recovery" << dendl;
 486       return false;  // don't mess with file size probing
 487     }
 488     if (in->get_num_ref() > (int)in->is_dirty() + (int)in->is_dirty_parent()) {
 489       dout(20) << " too many inode refs" << dendl;
 490       return false;
 491     }
 492     if (dn->get_num_ref() > (int)dn->is_dirty() + !!in->get_num_ref()) {
 493       dout(20) << " too many dn refs" << dendl;
 494       return false;
 495     }
 496     if (delay) {
 497       if (!dn->item_stray.is_on_list()) {
 498         delayed_eval_stray.push_back(&dn->item_stray);
 499         num_strays_delayed++;
 500         logger->set(l_mdc_num_strays_delayed, num_strays_delayed);
 501       }
 502     // don't purge multiversion inode with snap data
 503     } else if (in->snaprealm && in->snaprealm->has_past_parents() &&
 504               !in->old_inodes.empty()) {
 505       // A file with snapshots: we will truncate the HEAD revision
 506       // but leave the metadata intact.
 507       assert(!in->is_dir());
 508       dout(20) << " file has past parents "
 509         << in->snaprealm->srnode.past_parents << dendl;
 510       if (in->is_file() && in->get_projected_inode()->size > 0) {
 511         enqueue(dn, true); // truncate head objects
 512       }
 513     } else {
 514       // A straightforward file, ready to be purged.  Enqueue it.
 515       if (in->is_dir()) {
 516         in->close_dirfrags();
 517       }
 518
 519       enqueue(dn, false);
 520     }
 521
 522     return true;
 523   } else {
 524     /*
 525      * Where a stray has some links, they should be remotes, check
 526      * if we can do anything with them if we happen to have them in
 527      * cache.
 528      */
 529     _eval_stray_remote(dn, NULL);
 530     return false;
 531   }
 532 }
 533
 534 void StrayManager::activate()
 535 {
 536   dout(10) << __func__ << dendl;
 537   started = true;
 538   purge_queue.activate();
 539 }
 540
 541 bool StrayManager::eval_stray(CDentry *dn, bool delay)
 542 {
 543   // avoid nested eval_stray
 544   if (dn->state_test(CDentry::STATE_EVALUATINGSTRAY))
 545       return false;
 546
 547   dn->state_set(CDentry::STATE_EVALUATINGSTRAY);
 548   bool ret = _eval_stray(dn, delay);
 549   dn->state_clear(CDentry::STATE_EVALUATINGSTRAY);
 550   return ret;
 551 }
 552
 553 void StrayManager::eval_remote(CDentry *remote_dn)
 554 {
 555   dout(10) << __func__ << " " << *remote_dn << dendl;
 556
 557   CDentry::linkage_t *dnl = remote_dn->get_projected_linkage();
 558   assert(dnl->is_remote());
 559   CInode *in = dnl->get_inode();
 560
 561   if (!in) {
 562     dout(20) << __func__ << ": no inode, cannot evaluate" << dendl;
 563     return;
 564   }
 565
 566   if (remote_dn->last != CEPH_NOSNAP) {
 567     dout(20) << __func__ << ": snap dentry, cannot evaluate" << dendl;
 568     return;
 569   }
 570
 571   // refers to stray?
 572   CDentry *primary_dn = in->get_projected_parent_dn();
 573   assert(primary_dn != NULL);
 574   if (primary_dn->get_dir()->get_inode()->is_stray()) {
 575     _eval_stray_remote(primary_dn, remote_dn);
 576   } else {
 577     dout(20) << __func__ << ": inode's primary dn not stray" << dendl;
 578   }
 579 }
 580
 581 class C_RetryEvalRemote : public StrayManagerContext {
 582   CDentry *dn;
 583   public:
 584     C_RetryEvalRemote(StrayManager *sm_, CDentry *dn_) :
 585       StrayManagerContext(sm_), dn(dn_) {
 586       dn->get(CDentry::PIN_PTRWAITER);
 587     }
 588     void finish(int r) override {
 589       if (dn->get_projected_linkage()->is_remote())
 590         sm->eval_remote(dn);
 591       dn->put(CDentry::PIN_PTRWAITER);
 592     }
 593 };
 594
 595 void StrayManager::_eval_stray_remote(CDentry *stray_dn, CDentry *remote_dn)
 596 {
 597   dout(20) << __func__ << " " << *stray_dn << dendl;
 598   assert(stray_dn != NULL);
 599   assert(stray_dn->get_dir()->get_inode()->is_stray());
 600   CDentry::linkage_t *stray_dnl = stray_dn->get_projected_linkage();
 601   assert(stray_dnl->is_primary());
 602   CInode *stray_in = stray_dnl->get_inode();
 603   assert(stray_in->inode.nlink >= 1);
 604   assert(stray_in->last == CEPH_NOSNAP);
 605
 606   /* If no remote_dn hinted, pick one arbitrarily */
 607   if (remote_dn == NULL) {
 608     if (!stray_in->remote_parents.empty()) {
 609       for (compact_set<CDentry*>::iterator p = stray_in->remote_parents.begin();
 610            p != stray_in->remote_parents.end();
 611            ++p)
 612         if ((*p)->last == CEPH_NOSNAP && !(*p)->is_projected()) {
 613           if ((*p)->is_auth()) {
 614             remote_dn = *p;
 615             if (remote_dn->dir->can_auth_pin())
 616               break;
 617           } else if (!remote_dn) {
 618             remote_dn = *p;
 619           }
 620         }
 621     }
 622     if (!remote_dn) {
 623       dout(20) << __func__ << ": not reintegrating (no remote parents in cache)" << dendl;
 624       return;
 625     }
 626   }
 627   assert(remote_dn->last == CEPH_NOSNAP);
 628   // NOTE: we repeat this check in _rename(), since our submission path is racey.
 629   if (!remote_dn->is_projected()) {
 630     if (remote_dn->is_auth()) {
 631       if (remote_dn->dir->can_auth_pin()) {
 632         reintegrate_stray(stray_dn, remote_dn);
 633       } else {
 634         remote_dn->dir->add_waiter(CDir::WAIT_UNFREEZE, new C_RetryEvalRemote(this, remote_dn));
 635         dout(20) << __func__ << ": not reintegrating (can't authpin remote parent)" << dendl;
 636       }
 637
 638     } else if (!remote_dn->is_auth() && stray_dn->is_auth()) {
 639       migrate_stray(stray_dn, remote_dn->authority().first);
 640     } else {
 641       dout(20) << __func__ << ": not reintegrating" << dendl;
 642     }
 643   } else {
 644     // don't do anything if the remote parent is projected, or we may
 645     // break user-visible semantics!
 646     dout(20) << __func__ << ": not reintegrating (projected)" << dendl;
 647   }
 648 }
 649
 650 void StrayManager::reintegrate_stray(CDentry *straydn, CDentry *rdn)
 651 {
 652   dout(10) << __func__ << " " << *straydn << " into " << *rdn << dendl;
 653
 654   logger->inc(l_mdc_strays_reintegrated);
 655
 656   // rename it to another mds.
 657   filepath src;
 658   straydn->make_path(src);
 659   filepath dst;
 660   rdn->make_path(dst);
 661
 662   MClientRequest *req = new MClientRequest(CEPH_MDS_OP_RENAME);
 663   req->set_filepath(dst);
 664   req->set_filepath2(src);
 665   req->set_tid(mds->issue_tid());
 666
 667   mds->send_message_mds(req, rdn->authority().first);
 668 }
 669
 670 void StrayManager::migrate_stray(CDentry *dn, mds_rank_t to)
 671 {
 672   CInode *in = dn->get_projected_linkage()->get_inode();
 673   assert(in);
 674   CInode *diri = dn->dir->get_inode();
 675   assert(diri->is_stray());
 676   dout(10) << "migrate_stray from mds." << MDS_INO_STRAY_OWNER(diri->inode.ino)
 677            << " to mds." << to
 678            << " " << *dn << " " << *in << dendl;
 679
 680   logger->inc(l_mdc_strays_migrated);
 681
 682   // rename it to another mds.
 683   filepath src;
 684   dn->make_path(src);
 685   assert(src.depth() == 2);
 686
 687   filepath dst(MDS_INO_MDSDIR(to));
 688   dst.push_dentry(src[0]);
 689   dst.push_dentry(src[1]);
 690
 691   MClientRequest *req = new MClientRequest(CEPH_MDS_OP_RENAME);
 692   req->set_filepath(dst);
 693   req->set_filepath2(src);
 694   req->set_tid(mds->issue_tid());
 695
 696   mds->send_message_mds(req, to);
 697 }
 698
 699 StrayManager::StrayManager(MDSRank *mds, PurgeQueue &purge_queue_)
 700   : delayed_eval_stray(member_offset(CDentry, item_stray)),
 701     mds(mds), logger(NULL), started(false), num_strays(0),
 702     num_strays_delayed(0), num_strays_enqueuing(0),
 703     purge_queue(purge_queue_)
 704 {
 705   assert(mds != NULL);
 706 }
 707
 708 void StrayManager::truncate(CDentry *dn)
 709 {
 710   const CDentry::linkage_t *dnl = dn->get_projected_linkage();
 711   const CInode *in = dnl->get_inode();
 712   assert(in);
 713   dout(10) << __func__ << ": " << *dn << " " << *in << dendl;
 714   assert(!dn->is_replicated());
 715
 716   const SnapRealm *realm = in->find_snaprealm();
 717   assert(realm);
 718   dout(10) << " realm " << *realm << dendl;
 719   const SnapContext *snapc = &realm->get_snap_context();
 720
 721   uint64_t to = in->inode.get_max_size();
 722   to = MAX(in->inode.size, to);
 723   // when truncating a file, the filer does not delete stripe objects that are
 724   // truncated to zero. so we need to purge stripe objects up to the max size
 725   // the file has ever been.
 726   to = MAX(in->inode.max_size_ever, to);
 727
 728   assert(to > 0);
 729
 730   PurgeItem item;
 731   item.ino = in->inode.ino;
 732   item.layout = in->inode.layout;
 733   item.snapc = *snapc;
 734   item.size = to;
 735
 736   purge_queue.push(item, new C_IO_PurgeStrayPurged(
 737         this, dn, true));
 738 }
 739
 740 void StrayManager::_truncate_stray_logged(CDentry *dn, LogSegment *ls)
 741 {
 742   CInode *in = dn->get_projected_linkage()->get_inode();
 743
 744   dout(10) << __func__ << ": " << *dn << " " << *in << dendl;
 745
 746   dn->state_clear(CDentry::STATE_PURGING | CDentry::STATE_PURGINGPINNED);
 747   dn->put(CDentry::PIN_PURGING);
 748
 749   in->pop_and_dirty_projected_inode(ls);
 750
 751   eval_stray(dn);
 752 }
 753