From: Zhi Zhang <willzzhang@tencent.com>
Date: Tue, 12 Feb 2019 02:44:31 +0000 (+0800)
Subject: mds: fix potential re-evaluate stray dentry in _unlink_local_finish
X-Git-Tag: v13.2.5~18^2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=27b6f67b56f0330f00b80d0311d518862cbf0608;p=ceph.git

mds: fix potential re-evaluate stray dentry in _unlink_local_finish

If MDS handles cap release before _unlink_local_finish, then when MDS
processes _unlink_local_finish, eval_stray might be re-entered twice,
so this will cause crashing.

Fixes: http://tracker.ceph.com/issues/38263

Signed-off-by: Zhi Zhang <zhangz.david@outlook.com>
(cherry picked from commit 72c93baac64211e9f02fa01e743451bf5d63d7a6)

Conflicts:
	src/mds/MDCache.h : Resolved in notify_stray
---

diff --git a/src/mds/MDCache.h b/src/mds/MDCache.h
index b8633c4945f..95cf75d2acb 100644
--- a/src/mds/MDCache.h
+++ b/src/mds/MDCache.h
@@ -193,6 +193,9 @@ public:
    */
   void notify_stray(CDentry *dn) {
     assert(dn->get_dir()->get_inode()->is_stray());
+    if (dn->state_test(CDentry::STATE_PURGING))
+      return;
+
     stray_manager.eval_stray(dn);
   }