mds: handle freeze authpin race

For across authority rename, the MDS first freezes the source inode's
authpin. It happens while the source dentry isn't locked. So when the
inode's authpin become frozen, the source dentry may have changed and
be linked to a different inode.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>

diff --git a/src/mds/Mutation.cc b/src/mds/Mutation.cc
index 3916b2a1a338440eb4f56f0eed0a0f90f65fc457..0bf5475fae18ba7d0de96dd4bfa8b01379da6843 100644 (file)
--- a/src/mds/Mutation.cc
+++ b/src/mds/Mutation.cc
@@ -226,7 +226,7 @@ bool MDRequest::freeze_auth_pin(CInode *inode)
   return true;
 }
 
-void MDRequest::unfreeze_auth_pin()
+void MDRequest::unfreeze_auth_pin(bool clear_inode)
 {
   assert(more()->is_freeze_authpin);
   CInode *inode = more()->rename_inode;
@@ -235,6 +235,8 @@ void MDRequest::unfreeze_auth_pin()
   else
     inode->unfreeze_inode();
   more()->is_freeze_authpin = false;
+  if (clear_inode)
+    more()->rename_inode = NULL;
 }
 
 void MDRequest::set_remote_frozen_auth_pin(CInode *inode)
@@ -273,7 +275,7 @@ bool MDRequest::can_auth_pin(MDSCacheObject *object)
 void MDRequest::drop_local_auth_pins()
 {
   if (has_more() && more()->is_freeze_authpin)
-    unfreeze_auth_pin();
+    unfreeze_auth_pin(true);
   Mutation::drop_local_auth_pins();
 }
 

diff --git a/src/mds/Mutation.h b/src/mds/Mutation.h
index 92750bef2f40ea37a4cf02cebafda0a3deccb914..206b71a9158dd1b772324845aef96d983559353f 100644 (file)
--- a/src/mds/Mutation.h
+++ b/src/mds/Mutation.h
@@ -312,7 +312,7 @@ struct MDRequest : public Mutation {
   bool slave_did_prepare();
   bool did_ino_allocation();
   bool freeze_auth_pin(CInode *inode);
-  void unfreeze_auth_pin();
+  void unfreeze_auth_pin(bool clear_inode=false);
   void set_remote_frozen_auth_pin(CInode *inode);
   bool can_auth_pin(MDSCacheObject *object);
   void drop_local_auth_pins();

diff --git a/src/mds/Server.cc b/src/mds/Server.cc
index 33870d1bc6eafa595ff53bd96a0e77621b75c00c..984ad2909d8c2ed749d6f432f71963127dbc20eb 100644 (file)
--- a/src/mds/Server.cc
+++ b/src/mds/Server.cc
@@ -1679,6 +1679,11 @@ void Server::handle_slave_auth_pin(MDRequest *mdr)
   if (fail) {
     mdr->drop_local_auth_pins();  // just in case
   } else {
+    /* freeze authpin wrong inode */
+    if (mdr->has_more() && mdr->more()->is_freeze_authpin &&
+       mdr->more()->rename_inode != auth_pin_freeze)
+      mdr->unfreeze_auth_pin(true);
+
     /* handle_slave_rename_prep() call freeze_inode() to wait for all other operations
      * on the source inode to complete. This happens after all locks for the rename
      * operation are acquired. But to acquire locks, we need auth pin locks' parent