Simpler fdatasync hack

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index cc6eaa2..16530b9 100644 (file)
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -368,6 +368,12 @@ static int mdb_mutex_failed(MDB_env *env, mdb_mutex_t *mutex, int rc);
  */
 #ifndef MDB_FDATASYNC
 # define MDB_FDATASYNC fdatasync
+# ifndef MDB_SAFE_FDATASYNC
+/** Linux ext3fs and ext4fs don't implement fdatasync correctly
+ *     on older kernels. xfs is known to be safe. https://lkml.org/lkml/2012/9/3/83
+ */
+#  define      MDB_BROKEN_FDATASYNC
+# endif
 #endif
 
 #ifndef MDB_MSYNC
@@ -1154,7 +1160,7 @@ struct MDB_env {
        MDB_txn         *me_txn;                /**< current write transaction */
        MDB_txn         *me_txn0;               /**< prealloc'd write transaction */
        size_t          me_mapsize;             /**< size of the data memory map */
-       off_t           me_size;                /**< current file size */
+       size_t          me_size;                /**< current file size */
        pgno_t          me_maxpg;               /**< me_mapsize / me_psize */
        MDB_dbx         *me_dbxs;               /**< array of static DB info */
        uint16_t        *me_dbflags;    /**< array of flags from MDB_db.md_flags */
@@ -2341,6 +2347,10 @@ fail:
        return rc;
 }
 
+#ifdef MDB_BROKEN_FDATASYNC
+static int ESECT mdb_fsize(HANDLE fd, size_t *size);
+#endif
+
 int
 mdb_env_sync(MDB_env *env, int force)
 {
@@ -2356,6 +2366,15 @@ mdb_env_sync(MDB_env *env, int force)
                                rc = ErrCode();
 #endif
                } else {
+#ifdef MDB_BROKEN_FDATASYNC
+                       size_t sz = 0;
+                       if (mdb_fsize(env->me_fd, &sz) != MDB_SUCCESS || sz != env->me_size) {
+                               if (fsync(env->me_fd))
+                                       rc = ErrCode();
+                               else if (sz)
+                                       env->me_size = sz;
+                       } else
+#endif
                        if (MDB_FDATASYNC(env->me_fd))
                                rc = ErrCode();
                }