mds: wait reintegrate to finish when unlinking

When unlinking a remote dentry while primary dentry has been just
unlinked and was trying to reintegrate, which will finally be a
RENAME client request to current MDS, the stray dentry.

If the RENAME request is sleeping and waiting for some resources
just after authpin the CInode, so the unlinking request will mark
the remote dentry as UNLINKING state and then add itself to the
wait list just waiting for the CInode to be authpined.

Then after the RENAME request is retried later it will add to a
wait list again and waiting for the UNLINKING state to be cleared.
And finally the RENAME and UNLINK requests will be deadlock.

This fix will block the UNLINK request if the reintegrate_stray
is going on for current dentry.

Fixes: https://tracker.ceph.com/issues/58340
Signed-off-by: Xiubo Li <xiubli@redhat.com>

diff --git a/src/mds/CDentry.cc b/src/mds/CDentry.cc
index 55f2191346fa558c07f8c68711fe37111c8cc96f..6f20f53d144da61e3a95fb81384e5655f64bbab4 100644 (file)
--- a/src/mds/CDentry.cc
+++ b/src/mds/CDentry.cc
@@ -108,6 +108,8 @@ ostream& operator<<(ostream& out, const CDentry& dn)
   out << " state=" << dn.get_state();
   if (dn.is_new()) out << "|new";
   if (dn.state_test(CDentry::STATE_BOTTOMLRU)) out << "|bottomlru";
+  if (dn.state_test(CDentry::STATE_UNLINKING)) out << "|unlinking";
+  if (dn.state_test(CDentry::STATE_REINTEGRATING)) out << "|reintegrating";
 
   if (dn.get_num_ref()) {
     out << " |";

diff --git a/src/mds/CDentry.h b/src/mds/CDentry.h
index 3f715de2f7e056a173348337548ec763fb6ed0ab..0d468c6f07428e35ff83989714ccb03ddb4bf378 100644 (file)
--- a/src/mds/CDentry.h
+++ b/src/mds/CDentry.h
@@ -87,6 +87,7 @@ public:
   static const int STATE_PURGINGPINNED =  (1<<5);
   static const int STATE_BOTTOMLRU =    (1<<6);
   static const int STATE_UNLINKING =    (1<<7);
+  static const int STATE_REINTEGRATING = (1<<8);
   // stray dentry needs notification of releasing reference
   static const int STATE_STRAY =       STATE_NOTIFYREF;
   static const int MASK_STATE_IMPORT_KEPT = STATE_BOTTOMLRU;
@@ -100,8 +101,9 @@ public:
 
   static const unsigned EXPORT_NONCE = 1;
 
-  const static uint64_t WAIT_UNLINK_STATE  = (1<<0);
-  const static uint64_t WAIT_UNLINK_FINISH = (1<<1);
+  const static uint64_t WAIT_UNLINK_STATE       = (1<<0);
+  const static uint64_t WAIT_UNLINK_FINISH      = (1<<1);
+  const static uint64_t WAIT_REINTEGRATE_FINISH = (1<<2);
   uint32_t replica_unlinking_ref = 0;
 
   CDentry(std::string_view n, __u32 h,

diff --git a/src/mds/MDSRank.cc b/src/mds/MDSRank.cc
index 6b8b24d808e0dc45b5c002134dc8e64602f4d30e..6ebbd880c64b7cd34f1a089c790ff5c21d35375a 100644 (file)
--- a/src/mds/MDSRank.cc
+++ b/src/mds/MDSRank.cc
@@ -1178,6 +1178,7 @@ bool MDSRank::is_valid_message(const cref_t<Message> &m) {
       type == CEPH_MSG_CLIENT_RECONNECT ||
       type == CEPH_MSG_CLIENT_RECLAIM ||
       type == CEPH_MSG_CLIENT_REQUEST ||
+      type == CEPH_MSG_CLIENT_REPLY ||
       type == MSG_MDS_PEER_REQUEST ||
       type == MSG_MDS_HEARTBEAT ||
       type == MSG_MDS_TABLE_REQUEST ||
@@ -1231,6 +1232,7 @@ void MDSRank::handle_message(const cref_t<Message> &m)
       ALLOW_MESSAGES_FROM(CEPH_ENTITY_TYPE_CLIENT);
       // fall-thru
     case CEPH_MSG_CLIENT_REQUEST:
+    case CEPH_MSG_CLIENT_REPLY:
       server->dispatch(m);
       break;
     case MSG_MDS_PEER_REQUEST:

diff --git a/src/mds/MDSRank.h b/src/mds/MDSRank.h
index c00af5fe084187aebda03b40f59ab9ea2d83311a..3e353cf962bc971a5de5b0403ca9f6a05c464cbe 100644 (file)
--- a/src/mds/MDSRank.h
+++ b/src/mds/MDSRank.h
@@ -151,6 +151,29 @@ class Finisher;
 class ScrubStack;
 class C_ExecAndReply;
 
+struct MDSMetaRequest {
+private:
+  int _op;
+  CDentry *_dentry;
+  ceph_tid_t _tid;
+public:
+  explicit MDSMetaRequest(int op, CDentry *dn, ceph_tid_t tid) :
+    _op(op), _dentry(dn), _tid(tid) {
+    if (_dentry) {
+      _dentry->get(CDentry::PIN_PURGING);
+    }
+  }
+  ~MDSMetaRequest() {
+    if (_dentry) {
+      _dentry->put(CDentry::PIN_PURGING);
+    }
+  }
+
+  CDentry *get_dentry() { return _dentry; }
+  int get_op() { return _op; }
+  ceph_tid_t get_tid() { return _tid; }
+};
+
 /**
  * The public part of this class's interface is what's exposed to all
  * the various subsystems (server, mdcache, etc), such as pointers
@@ -416,6 +439,8 @@ class MDSRank {
     PerfCounters *logger = nullptr, *mlogger = nullptr;
     OpTracker op_tracker;
 
+    std::map<ceph_tid_t, MDSMetaRequest> internal_client_requests;
+
     // The last different state I held before current
     MDSMap::DaemonState last_state = MDSMap::STATE_BOOT;
     // The state assigned to me by the MDSMap

diff --git a/src/mds/Server.cc b/src/mds/Server.cc
index d7ae5836c9ade547a15bce896753e8ee182e9593..c43e995928d9e9617bc3fc94495239ef5ead6536 100644 (file)
--- a/src/mds/Server.cc
+++ b/src/mds/Server.cc
@@ -31,6 +31,7 @@
 #include "Mutation.h"
 #include "MetricsHandler.h"
 #include "cephfs_features.h"
+#include "MDSContext.h"
 
 #include "msg/Messenger.h"
 
@@ -360,6 +361,9 @@ void Server::dispatch(const cref_t<Message> &m)
   case CEPH_MSG_CLIENT_REQUEST:
     handle_client_request(ref_cast<MClientRequest>(m));
     return;
+  case CEPH_MSG_CLIENT_REPLY:
+    handle_client_reply(ref_cast<MClientReply>(m));
+    return;
   case CEPH_MSG_CLIENT_RECLAIM:
     handle_client_reclaim(ref_cast<MClientReclaim>(m));
     return;
@@ -2296,6 +2300,10 @@ void Server::reply_client_request(MDRequestRef& mdr, const ref_t<MClientReply> &
     mds->send_message_client(reply, session);
   }
 
+  if (client_inst.name.is_mds() && reply->get_op() == CEPH_MDS_OP_RENAME) {
+    mds->send_message(reply, mdr->client_request->get_connection());
+  }
+
   if (req->is_queued_for_replay() &&
       (mdr->has_completed || reply->get_result() < 0)) {
     if (reply->get_result() < 0) {
@@ -2528,6 +2536,38 @@ void Server::handle_client_request(const cref_t<MClientRequest> &req)
   return;
 }
 
+void Server::handle_client_reply(const cref_t<MClientReply> &reply)
+{
+  dout(4) << "handle_client_reply " << *reply << dendl;
+
+  ceph_assert(reply->is_safe());
+  ceph_tid_t tid = reply->get_tid();
+
+  if (mds->internal_client_requests.count(tid) == 0) {
+    dout(1) << " no pending request on tid " << tid << dendl;
+    return;
+  }
+
+  auto &req = mds->internal_client_requests.at(tid);
+  CDentry *dn = req.get_dentry();
+
+  switch (reply->get_op()) {
+  case CEPH_MDS_OP_RENAME:
+    if (dn) {
+      dn->state_clear(CDentry::STATE_REINTEGRATING);
+
+      MDSContext::vec finished;
+      dn->take_waiting(CDentry::WAIT_REINTEGRATE_FINISH, finished);
+      mds->queue_waiters(finished);
+    }
+    break;
+  default:
+    dout(5) << " unknown client op " << reply->get_op() << dendl;
+  }
+
+  mds->internal_client_requests.erase(tid);
+}
+
 void Server::handle_osd_map()
 {
   /* Note that we check the OSDMAP_FULL flag directly rather than
@@ -6844,6 +6884,45 @@ void Server::wait_for_pending_unlink(CDentry *dn, MDRequestRef& mdr)
   dn->add_waiter(CDentry::WAIT_UNLINK_FINISH, new C_WaitUnlinkToFinish(mdcache, dn, fin));
 }
 
+struct C_WaitReintegrateToFinish : public MDSContext {
+protected:
+  MDCache *mdcache;
+  CDentry *dn;
+  MDSContext *fin;
+
+  MDSRank *get_mds() override
+  {
+    ceph_assert(mdcache != NULL);
+    return mdcache->mds;
+  }
+
+public:
+  C_WaitReintegrateToFinish(MDCache *m, CDentry *d, MDSContext *f) :
+    mdcache(m), dn(d), fin(f) {}
+  void finish(int r) override {
+    fin->complete(r);
+    dn->put(CDentry::PIN_PURGING);
+  }
+};
+
+bool Server::is_reintegrate_pending(CDentry *dn)
+{
+  CDentry::linkage_t *dnl = dn->get_projected_linkage();
+  if (!dnl->is_null() && dn->state_test(CDentry::STATE_REINTEGRATING)) {
+      return true;
+  }
+  return false;
+}
+
+void Server::wait_for_pending_reintegrate(CDentry *dn, MDRequestRef& mdr)
+{
+  dout(20) << __func__ << " dn " << *dn << dendl;
+  mds->locker->drop_locks(mdr.get());
+  auto fin = new C_MDS_RetryRequest(mdcache, mdr);
+  dn->get(CDentry::PIN_PURGING);
+  dn->add_waiter(CDentry::WAIT_REINTEGRATE_FINISH, new C_WaitReintegrateToFinish(mdcache, dn, fin));
+}
+
 // MKNOD
 
 class C_MDS_mknod_finish : public ServerLogContext {
@@ -7914,6 +7993,11 @@ void Server::handle_client_unlink(MDRequestRef& mdr)
   if (!dn)
     return;
 
+  if (is_reintegrate_pending(dn)) {
+    wait_for_pending_reintegrate(dn, mdr);
+    return;
+  }
+
   // notify replica MDSes the dentry is under unlink
   if (!dn->state_test(CDentry::STATE_UNLINKING)) {
     dn->state_set(CDentry::STATE_UNLINKING);

diff --git a/src/mds/Server.h b/src/mds/Server.h
index ba38ccb2db4e680d46bc36bf2ca220b18801be26..1d5518fdf31e765e2f4af79583d6407e6d421e8f 100644 (file)
--- a/src/mds/Server.h
+++ b/src/mds/Server.h
@@ -159,6 +159,7 @@ public:
 
   // -- requests --
   void handle_client_request(const cref_t<MClientRequest> &m);
+  void handle_client_reply(const cref_t<MClientReply> &m);
 
   void journal_and_reply(MDRequestRef& mdr, CInode *tracei, CDentry *tracedn,
                         LogEvent *le, MDSLogContextBase *fin);
@@ -238,6 +239,9 @@ public:
   bool is_unlink_pending(CDentry *dn);
   void wait_for_pending_unlink(CDentry *dn, MDRequestRef& mdr);
 
+  bool is_reintegrate_pending(CDentry *dn);
+  void wait_for_pending_reintegrate(CDentry *dn, MDRequestRef& mdr);
+
   // open
   void handle_client_open(MDRequestRef& mdr);
   void handle_client_openc(MDRequestRef& mdr);  // O_CREAT variant.

diff --git a/src/mds/StrayManager.cc b/src/mds/StrayManager.cc
index f57c5fe509f243d4f14c65efe491b3823dca6e1d..d5827d48002c55b179818ab67002ec3340e76774 100644 (file)
--- a/src/mds/StrayManager.cc
+++ b/src/mds/StrayManager.cc
@@ -687,19 +687,27 @@ void StrayManager::reintegrate_stray(CDentry *straydn, CDentry *rdn)
   dout(10) << __func__ << " " << *straydn << " to " << *rdn << dendl;
 
   logger->inc(l_mdc_strays_reintegrated);
-  
+
   // rename it to remote linkage .
   filepath src(straydn->get_name(), straydn->get_dir()->ino());
   filepath dst(rdn->get_name(), rdn->get_dir()->ino());
 
+  ceph_tid_t tid = mds->issue_tid();
+
   auto req = make_message<MClientRequest>(CEPH_MDS_OP_RENAME);
   req->set_filepath(dst);
   req->set_filepath2(src);
-  req->set_tid(mds->issue_tid());
+  req->set_tid(tid);
+
+  rdn->state_set(CDentry::STATE_REINTEGRATING);
+  mds->internal_client_requests.emplace(std::piecewise_construct,
+                                        std::make_tuple(tid),
+                                        std::make_tuple(CEPH_MDS_OP_RENAME,
+                                                        rdn, tid));
 
   mds->send_message_mds(req, rdn->authority().first);
 }
- 
+
 void StrayManager::migrate_stray(CDentry *dn, mds_rank_t to)
 {
   dout(10) << __func__ << " " << *dn << " to mds." << to << dendl;
@@ -713,10 +721,17 @@ void StrayManager::migrate_stray(CDentry *dn, mds_rank_t to)
   filepath src(dn->get_name(), dirino);
   filepath dst(dn->get_name(), MDS_INO_STRAY(to, MDS_INO_STRAY_INDEX(dirino)));
 
+  ceph_tid_t tid = mds->issue_tid();
+
   auto req = make_message<MClientRequest>(CEPH_MDS_OP_RENAME);
   req->set_filepath(dst);
   req->set_filepath2(src);
-  req->set_tid(mds->issue_tid());
+  req->set_tid(tid);
+
+  mds->internal_client_requests.emplace(std::piecewise_construct,
+                                        std::make_tuple(tid),
+                                        std::make_tuple(CEPH_MDS_OP_RENAME,
+                                                        nullptr, tid));
 
   mds->send_message_mds(req, to);
 }