Import wiredtiger-wiredtiger-mongodb-3.2.0-rc1-194-g0dc3f20.tar.gz from wiredtiger branch mongodb-3.2

1 files changed, 17 insertions, 3 deletions

diff --git a/src/third_party/wiredtiger/src/meta/meta_table.c b/src/third_party/wiredtiger/src/meta/meta_table.c
index 0bab52b9d9c..e7074a9c1b5 100644
--- a/src/third_party/wiredtiger/src/meta/meta_table.c
+++ b/src/third_party/wiredtiger/src/meta/meta_table.c
@@ -151,8 +151,11 @@ __wt_metadata_update(
 	    key, value, WT_META_TRACKING(session) ? "true" : "false",
 	    __metadata_turtle(key) ? "" : "not "));
 
-	if (__metadata_turtle(key))
-		return (__wt_turtle_update(session, key, value));
+	if (__metadata_turtle(key)) {
+		WT_WITH_TURTLE_LOCK(session,
+		    ret = __wt_turtle_update(session, key, value));
+		return (ret);
+	}
 
 	if (WT_META_TRACKING(session))
 		WT_RET(__wt_meta_track_update(session, key));
@@ -219,9 +222,20 @@ __wt_metadata_search(
 	if (__metadata_turtle(key))
 		return (__wt_turtle_read(session, key, valuep));
 
+	/*
+	 * All metadata reads are at read-uncommitted isolation.  That's
+	 * because once a schema-level operation completes, subsequent
+	 * operations must see the current version of checkpoint metadata, or
+	 * they may try to read blocks that may have been freed from a file.
+	 * Metadata updates use non-transactional techniques (such as the
+	 * schema and metadata locks) to protect access to in-flight updates.
+	 */
 	WT_RET(__wt_metadata_cursor(session, NULL, &cursor));
 	cursor->set_key(cursor, key);
-	WT_ERR(cursor->search(cursor));
+	WT_WITH_TXN_ISOLATION(session, WT_ISO_READ_UNCOMMITTED,
+	    ret = cursor->search(cursor));
+	WT_ERR(ret);
+
 	WT_ERR(cursor->get_value(cursor, &value));
 	WT_ERR(__wt_strdup(session, value, valuep));