From: Yan, Zheng <zyan@redhat.com>
Date: Tue, 30 May 2017 12:10:55 +0000 (+0800)
Subject: mds: fix race between cross-authorty rename and mds failure
X-Git-Tag: v12.1.0~128^2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=refs%2Fpull%2F15125%2Fhead;p=ceph.git

mds: fix race between cross-authorty rename and mds failure

If auth mds of rename srcdn fails, bystander mds may need to rollback
corresponding slave rename. If corresponding slave rename is still
work-in-progress, we should interrupt the slave rename, make it do
nothing.

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
---

diff --git a/src/mds/MDCache.cc b/src/mds/MDCache.cc
index fd030e457aeca..e3ada0b1672cf 100644
--- a/src/mds/MDCache.cc
+++ b/src/mds/MDCache.cc
@@ -2938,6 +2938,13 @@ void MDCache::handle_mds_failure(mds_rank_t who)
 	dout(10) << " slave request " << *mdr << " uncommitted, will resolve shortly" << dendl;
 	add_ambiguous_slave_update(p->first, mdr->slave_to_mds);
       }
+    } else if (mdr->slave_request) {
+      MMDSSlaveRequest *slave_req = mdr->slave_request;
+      // FIXME: Slave rename request can arrive after we notice mds failure.
+      // 	This can cause mds to crash (does not affect integrity of FS).
+      if (slave_req->get_op() == MMDSSlaveRequest::OP_RENAMEPREP &&
+	  slave_req->srcdn_auth == who)
+	slave_req->mark_interrupted();
     }
     
     // failed node is slave?
diff --git a/src/mds/MDSDaemon.h b/src/mds/MDSDaemon.h
index 2abcd87fe0640..1c6a7d791a90d 100644
--- a/src/mds/MDSDaemon.h
+++ b/src/mds/MDSDaemon.h
@@ -40,7 +40,7 @@
 #include "Beacon.h"
 
 
-#define CEPH_MDS_PROTOCOL    29 /* cluster internal */
+#define CEPH_MDS_PROTOCOL    30 /* cluster internal */
 
 class MonClient;
 
diff --git a/src/mds/Server.cc b/src/mds/Server.cc
index 43ea584be1b1d..c330e170f2189 100644
--- a/src/mds/Server.cc
+++ b/src/mds/Server.cc
@@ -6920,6 +6920,8 @@ bool Server::_rename_prepare_witness(MDRequestRef& mdr, mds_rank_t who, set<mds_
     req->destdnpath.push_dentry(dn->name);
   if (straydn)
     mdcache->replicate_stray(straydn, who, req->stray);
+
+  req->srcdn_auth = mdr->more()->srcdn_auth_mds;
   
   // srcdn auth will verify our current witness list is sufficient
   req->witnesses = witnesse;
@@ -7470,7 +7472,17 @@ void Server::handle_slave_rename_prep(MDRequestRef& mdr)
 	   << " " << mdr->slave_request->srcdnpath 
 	   << " to " << mdr->slave_request->destdnpath
 	   << dendl;
-  
+
+  if (mdr->slave_request->is_interrupted()) {
+    dout(10) << " slave request interrupted, sending noop reply" << dendl;
+    MMDSSlaveRequest *reply= new MMDSSlaveRequest(mdr->reqid, mdr->attempt, MMDSSlaveRequest::OP_RENAMEPREPACK);
+    reply->mark_interrupted();
+    mds->send_message_mds(reply, mdr->slave_to_mds);
+    mdr->slave_request->put();
+    mdr->slave_request = 0;
+    return;
+  }
+
   // discover destdn
   filepath destpath(mdr->slave_request->destdnpath);
   dout(10) << " dest " << destpath << dendl;
@@ -8233,7 +8245,9 @@ void Server::handle_slave_rename_prep_ack(MDRequestRef& mdr, MMDSSlaveRequest *a
 
   // witnessed?  or add extra witnesses?
   assert(mdr->more()->witnessed.count(from) == 0);
-  if (ack->witnesses.empty()) {
+  if (ack->is_interrupted()) {
+    dout(10) << " slave request interrupted, noop" << dendl;
+  } else if (ack->witnesses.empty()) {
     mdr->more()->witnessed.insert(from);
     if (!ack->is_not_journaled())
       mdr->more()->has_journaled_slaves = true;
diff --git a/src/messages/MMDSSlaveRequest.h b/src/messages/MMDSSlaveRequest.h
index 5512c5a0721e6..9e7510c9a6df8 100644
--- a/src/messages/MMDSSlaveRequest.h
+++ b/src/messages/MMDSSlaveRequest.h
@@ -101,6 +101,7 @@ class MMDSSlaveRequest : public Message {
   static const unsigned FLAG_NOTJOURNALED =	1<<2;
   static const unsigned FLAG_EROFS =		1<<3;
   static const unsigned FLAG_ABORT =		1<<4;
+  static const unsigned FLAG_INTERRUPTED =	1<<5;
 
   // for locking
   __u16 lock_type;  // lock object type
@@ -117,6 +118,7 @@ class MMDSSlaveRequest : public Message {
   bufferlist inode_export;
   version_t inode_export_v;
   bufferlist srci_replica;
+  mds_rank_t srcdn_auth;
   utime_t op_stamp;
 
   bufferlist stray;  // stray dir + dentry
@@ -142,6 +144,8 @@ public:
   bool is_error_rofs() { return (flags & FLAG_EROFS); }
   bool is_abort() { return (flags & FLAG_ABORT); }
   void mark_abort() { flags |= FLAG_ABORT; }
+  bool is_interrupted() { return (flags & FLAG_INTERRUPTED); }
+  void mark_interrupted() { flags |= FLAG_INTERRUPTED; }
 
   void set_lock_type(int t) { lock_type = t; }
 
@@ -151,7 +155,7 @@ public:
   MMDSSlaveRequest(metareqid_t ri, __u32 att, int o) : 
     Message(MSG_MDS_SLAVE_REQUEST),
     reqid(ri), attempt(att), op(o), flags(0), lock_type(0),
-    inode_export_v(0) { }
+    inode_export_v(0), srcdn_auth(MDS_RANK_NONE) { }
 private:
   ~MMDSSlaveRequest() override {}
 
@@ -170,6 +174,7 @@ public:
     ::encode(op_stamp, payload);
     ::encode(inode_export, payload);
     ::encode(inode_export_v, payload);
+    ::encode(srcdn_auth, payload);
     ::encode(srci_replica, payload);
     ::encode(stray, payload);
   }
@@ -188,6 +193,7 @@ public:
     ::decode(op_stamp, p);
     ::decode(inode_export, p);
     ::decode(inode_export_v, p);
+    ::decode(srcdn_auth, p);
     ::decode(srci_replica, p);
     ::decode(stray, p);
   }