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>
(cherry picked from commit c3b36723defae32b0a3ef1ac37b58ec57d356b65)

diff --git a/src/mds/CDentry.cc b/src/mds/CDentry.cc
index a2a7985996a8d4069a23357eafa4c8ca49d20c1a..7366ecd928a0344eefb9671832acdbb24f8413aa 100644 (file)
--- a/src/mds/CDentry.cc
+++ b/src/mds/CDentry.cc
@@ -104,6 +104,8 @@ 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 03932285cf7614dcb7851424fa516c851cc3b9a8..c7f83d1710a254aa4a4bfaae3c95329fcaa0b1d8 100644 (file)
--- a/src/mds/CDentry.h
+++ b/src/mds/CDentry.h
@@ -88,6 +88,7 @@ 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;
@@ -101,8 +102,9 @@ 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 4f286af7030f84e39bd0cd7e80b27ddb35a0d297..d2953c4efe97f4234c777a805194d80b05c75f19 100644 (file)
--- a/src/mds/MDSRank.cc
+++ b/src/mds/MDSRank.cc
@@ -1172,6 +1172,7 @@ 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 ||
@@ -1225,6 +1226,7 @@ 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 07f69721f8021bcb8fbc549b5b8f8ddadd5c8c71..847e949eabbe3b8c99af565312cc45a365cea7dc 100644 (file)
--- a/src/mds/MDSRank.h
+++ b/src/mds/MDSRank.h
@@ -150,6 +150,29 @@ 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 b8627e8e071c52a0b510bfc7af627b348c0507ad..996a57e007865466b38d3b3709a23b6f3fe81ffe 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"
 
@@ -354,6 +355,9 @@ 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;
@@ -2257,6 +2261,10 @@ 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) {
@@ -2488,6 +2496,38 @@ 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
@@ -6677,6 +6717,45 @@ 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 {
@@ -7739,6 +7818,11 @@ 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 91a01a19ee83a4af8b567a55030d14730f983af7..b48aa6a2404663c6fbb32470ec6cfe3ae07b657f 100644 (file)
--- a/src/mds/Server.h
+++ b/src/mds/Server.h
@@ -158,6 +158,7 @@ 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);
@@ -237,6 +238,9 @@ 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 de13b74395c0ef872462dc79735357f8c3269003..12bf508bdc6ce3d8a7da87702be86527d6f3e49c 100644 (file)
--- a/src/mds/StrayManager.cc
+++ b/src/mds/StrayManager.cc
@@ -678,19 +678,27 @@ 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;
@@ -704,10 +712,17 @@ 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);
 }