svn commit: r539380 - in branches/2020Q2/databases/lmdb: . files

[Xin LI]

Author: delphij
Date: Tue Jun 16 21:54:58 2020
New Revision: 539380
URL: https://svnweb.freebsd.org/changeset/ports/539380

Log:
  MFH: r539379
  
  databases/lmdb: in db_env_close0(), destroy robust mutexes if we are
  the only remaining user.
  
  When closing an lmdb database, all memory and file descriptor resources
  are released, including the shared memory pages that contained the
  robust mutex.
  
  However, before this commit, prior to unmapping the pages that contained
  the robust mutexex, lmdb did not destroy the mutexes first.  This would
  create a problem when an application opens and closes a database, then
  open it again.
  
  According to libthr(3), by default, a shared lock backed by a mapped
  file in memory is automatically destroyed on the last unmap of the
  corresponding file' page, which is allowed by POSIX.
  
  After unmapping the shared pages, the kernel writes off all active
  robust mutexes associated with these pages.  However, the userland
  threading library still keeps the record (pshared_lookup in
  thr_pshared.c of libthr) for these objects as they are not really
  destroyed before, so that it don't have to ask the kernel every
  time when looking them up.
  
  Now, a later re-open of the database might have mapped the lock file
  to the same memory location.  Because the threading library have
  remembered the robust mutex object, it would just reuse it even though
  it was already invalid from kernel's point of view.  Unfortunately,
  regular lock operations would still work for this process.
  
  Should another lmdb process opens the same database, it would attempt
  to obtain the robust mutex (no longer recognized by kernel) because it
  would see another process holding a file lock, but that would fail
  because the robust mutex is invalid for the kernel.
  
  Explicitly destroy the mutex if we are the last remaining user to ensure
  the mutex is always in a known defined state.
  
  OpenLDAP ITS #9278
  
  With debugging help from:	kib
  PR:				244493
  Approved by:			ports-secteam

Modified:
  branches/2020Q2/databases/lmdb/Makefile
  branches/2020Q2/databases/lmdb/files/patch-mdb.c
Directory Properties:
  branches/2020Q2/   (props changed)

Modified: branches/2020Q2/databases/lmdb/Makefile
==============================================================================
--- branches/2020Q2/databases/lmdb/Makefile	Tue Jun 16 21:51:55 2020	(r539379)
+++ branches/2020Q2/databases/lmdb/Makefile	Tue Jun 16 21:54:58 2020	(r539380)
@@ -3,7 +3,7 @@
 
 PORTNAME=	lmdb
 PORTVERSION=	0.9.24
-PORTREVISION=	1
+PORTREVISION=	2
 DISTVERSIONPREFIX=	${PORTNAME:tu}_
 PORTEPOCH=	1
 CATEGORIES=	databases

Modified: branches/2020Q2/databases/lmdb/files/patch-mdb.c
==============================================================================
--- branches/2020Q2/databases/lmdb/files/patch-mdb.c	Tue Jun 16 21:51:55 2020	(r539379)
+++ branches/2020Q2/databases/lmdb/files/patch-mdb.c	Tue Jun 16 21:54:58 2020	(r539380)
@@ -5,10 +5,37 @@
  #endif
  
 -#if defined(__APPLE__) || defined (BSD) || defined(__FreeBSD_kernel__)
-+#if defined(__FreeBSD__)
-+#  define MDB_USE_POSIX_MUTEX	1
-+#  define MDB_USE_ROBUST	1
++#if defined(__FreeBSD__) && defined(__FreeBSD_version) && __FreeBSD_version >= 1100110
++# define MDB_USE_POSIX_MUTEX   1
++# define MDB_USE_ROBUST        1
 +#elif defined(__APPLE__) || defined (BSD) || defined(__FreeBSD_kernel__)
  # define MDB_USE_POSIX_SEM	1
  # define MDB_FDATASYNC		fsync
  #elif defined(ANDROID)
+@@ -1375,7 +1378,7 @@ static int	mdb_page_split(MDB_cursor *mc, MDB_val *new
+ static int  mdb_env_read_header(MDB_env *env, MDB_meta *meta);
+ static MDB_meta *mdb_env_pick_meta(const MDB_env *env);
+ static int  mdb_env_write_meta(MDB_txn *txn);
+-#ifdef MDB_USE_POSIX_MUTEX /* Drop unused excl arg */
++#if defined(MDB_USE_POSIX_MUTEX) && !defined(MDB_ROBUST_SUPPORTED) /* Drop unused excl arg */
+ # define mdb_env_close0(env, excl) mdb_env_close1(env)
+ #endif
+ static void mdb_env_close0(MDB_env *env, int excl);
+@@ -5127,6 +5130,17 @@ mdb_env_close0(MDB_env *env, int excl)
+ 				sem_unlink(env->me_txns->mti_rmname);
+ 				sem_unlink(env->me_txns->mti_wmname);
+ 			}
++		}
++#elif defined(MDB_ROBUST_SUPPORTED)
++		/* If we have the filelock:  If we are the
++		 * only remaining user, clean up robust
++		 * mutexes.
++		 */
++		if (excl == 0)
++			mdb_env_excl_lock(env, &excl);
++		if (excl > 0) {
++			pthread_mutex_destroy(env->me_txns->mti_rmutex);
++			pthread_mutex_destroy(env->me_txns->mti_wmutex);
+ 		}
+ #endif
+ 		munmap((void *)env->me_txns, (env->me_maxreaders-1)*sizeof(MDB_reader)+sizeof(MDB_txninfo));