Review places that set/clear session->dhandle, replace with macros. Change callers to save/restore if they need to release a handle after a call.

8 files changed, 37 insertions, 27 deletions

diff --git a/src/conn/conn_dhandle.c b/src/conn/conn_dhandle.c
index 8ed656d6416..a5512352f2c 100644
--- a/src/conn/conn_dhandle.c
+++ b/src/conn/conn_dhandle.c
@@ -475,16 +475,15 @@ __conn_btree_apply_internal(WT_SESSION_IMPL *session, WT_DATA_HANDLE *dhandle,
 	WT_DECL_RET;
 
 	/*
-	 * We need to pull the handle into the session handle
-	 * cache and make sure it's referenced to stop other
-	 * internal code dropping the handle (e.g in LSM when
-	 * cleaning up obsolete chunks). Holding the metadata
-	 * lock isn't enough.
+	 * We need to pull the handle into the session handle cache and make
+	 * sure it's referenced to stop other internal code dropping the handle
+	 * (e.g in LSM when cleaning up obsolete chunks).
 	 */
 	ret = __wt_session_get_btree(session,
 	    dhandle->name, dhandle->checkpoint, NULL, 0);
 	if (ret == 0) {
-		ret = func(session, cfg);
+		WT_SAVE_DHANDLE(session,
+		    ret = func(session, cfg));
 		if (WT_META_TRACKING(session))
 			WT_TRET(__wt_meta_track_handle_lock(session, 0));
 		else
@@ -550,12 +549,11 @@ __wt_conn_btree_apply_single(WT_SESSION_IMPL *session,
     int (*func)(WT_SESSION_IMPL *, const char *[]), const char *cfg[])
 {
 	WT_CONNECTION_IMPL *conn;
-	WT_DATA_HANDLE *dhandle, *saved_dhandle;
+	WT_DATA_HANDLE *dhandle;
 	WT_DECL_RET;
 	uint64_t bucket, hash;
 
 	conn = S2C(session);
-	saved_dhandle = session->dhandle;
 
 	WT_ASSERT(session, F_ISSET(session, WT_SESSION_HANDLE_LIST_LOCKED));
 
@@ -578,15 +576,14 @@ __wt_conn_btree_apply_single(WT_SESSION_IMPL *session,
 			 */
 			__wt_spin_lock(session, &dhandle->close_lock);
 			if (F_ISSET(dhandle, WT_DHANDLE_OPEN)) {
-				session->dhandle = dhandle;
-				ret = func(session, cfg);
+				WT_WITH_DHANDLE(session, dhandle,
+				    ret = func(session, cfg));
 			}
 			__wt_spin_unlock(session, &dhandle->close_lock);
 			WT_ERR(ret);
 		}
 
-err:	session->dhandle = saved_dhandle;
-	return (ret);
+err:	return (ret);
 }
 
 /*
diff --git a/src/conn/conn_stat.c b/src/conn/conn_stat.c
index be2172ea8d8..67814dc330b 100644
--- a/src/conn/conn_stat.c
+++ b/src/conn/conn_stat.c
@@ -193,6 +193,7 @@ static int
 __statlog_apply(WT_SESSION_IMPL *session, const char *cfg[])
 {
 	WT_DATA_HANDLE *dhandle;
+	WT_DECL_RET;
 	char **p;
 
 	WT_UNUSED(cfg);
@@ -201,8 +202,11 @@ __statlog_apply(WT_SESSION_IMPL *session, const char *cfg[])
 
 	/* Check for a match on the set of sources. */
 	for (p = S2C(session)->stat_sources; *p != NULL; ++p)
-		if (WT_PREFIX_MATCH(dhandle->name, *p))
-			return (__statlog_dump(session, dhandle->name, 0));
+		if (WT_PREFIX_MATCH(dhandle->name, *p)) {
+			WT_WITHOUT_DHANDLE(session,
+			    ret = __statlog_dump(session, dhandle->name, 0));
+			WT_RET(ret);
+		}
 	return (0);
 }
 
diff --git a/src/cursor/cur_stat.c b/src/cursor/cur_stat.c
index a473de39a33..bebce217a6a 100644
--- a/src/cursor/cur_stat.c
+++ b/src/cursor/cur_stat.c
@@ -335,20 +335,17 @@ static int
 __curstat_file_init(WT_SESSION_IMPL *session,
     const char *uri, const char *cfg[], WT_CURSOR_STAT *cst)
 {
-	WT_DATA_HANDLE *dhandle, *saved_dhandle;
+	WT_DATA_HANDLE *dhandle;
 	WT_DECL_RET;
 
-	/* Our caller may have their own open handles, don't overwrite them. */
-	saved_dhandle = session->dhandle;
-
 	WT_RET(__wt_session_get_btree_ckpt(session, uri, cfg, 0));
+	dhandle = session->dhandle;
 
 	/*
 	 * Fill in the data source statistics, and copy them to the cursor.
 	 * Optionally clear the data source statistics.
 	 */
 	if ((ret = __wt_btree_stat_init(session, cst)) == 0) {
-		dhandle = session->dhandle;
 		cst->u.dsrc_stats = dhandle->stats;
 		if (F_ISSET(cst, WT_CONN_STAT_CLEAR))
 			__wt_stat_refresh_dsrc_stats(&dhandle->stats);
@@ -357,8 +354,8 @@ __curstat_file_init(WT_SESSION_IMPL *session,
 
 	/* Release the handle, we're done with it. */
 	WT_TRET(__wt_session_release_btree(session));
+	WT_RET(ret);
 
-	session->dhandle = saved_dhandle;
 	return (ret);
 }
 
diff --git a/src/evict/evict_lru.c b/src/evict/evict_lru.c
index 83a9aa5c8c5..9f549d1f2fe 100644
--- a/src/evict/evict_lru.c
+++ b/src/evict/evict_lru.c
@@ -979,7 +979,7 @@ retry:	while (slot < max_entries && ret == 0) {
 		 * exclusive access when a handle is being closed.
 		 */
 		if (!F_ISSET(btree, WT_BTREE_NO_EVICTION)) {
-			WT_WITH_BTREE(session, btree,
+			WT_WITH_DHANDLE(session, dhandle,
 			    ret = __evict_walk_file(session, &slot, flags));
 			WT_ASSERT(session, session->split_gen == 0);
 		}
diff --git a/src/include/dhandle.h b/src/include/dhandle.h
index 423bb84d00d..300e8e735b9 100644
--- a/src/include/dhandle.h
+++ b/src/include/dhandle.h
@@ -6,6 +6,10 @@
  * See the file LICENSE for redistribution information.
  */
 
+/*
+ * Helpers for calling a function with a data handle in session->dhandle
+ * then restoring afterwards.
+ */
 #define	WT_WITH_DHANDLE(s, d, e) do {					\
 	WT_DATA_HANDLE *__saved_dhandle = (s)->dhandle;			\
 	(s)->dhandle = (d);						\
@@ -15,6 +19,15 @@
 
 #define	WT_WITH_BTREE(s, b, e)	WT_WITH_DHANDLE(s, (b)->dhandle, e)
 
+/* Call a function without the caller's data handle, restore afterwards. */
+#define	WT_WITHOUT_DHANDLE(s, e) WT_WITH_DHANDLE(s, NULL, e)
+
+/*
+ * Call a function with the caller's data handle, restore it afterwards in case
+ * it is overwritten.
+ */
+#define	WT_SAVE_DHANDLE(s, e) WT_WITH_DHANDLE(s, (s)->dhandle, e)
+
 /*
  * WT_DATA_HANDLE --
  *	A handle for a generic named data source.
diff --git a/src/meta/meta_apply.c b/src/meta/meta_apply.c
index 8ef5cc38db4..6d08ce3aa6a 100644
--- a/src/meta/meta_apply.c
+++ b/src/meta/meta_apply.c
@@ -43,7 +43,8 @@ __wt_meta_btree_apply(WT_SESSION_IMPL *session,
 		 */
 		ret = __wt_session_get_btree(session, uri, NULL, NULL, 0);
 		if (ret == 0) {
-			ret = func(session, cfg);
+			WT_SAVE_DHANDLE(session,
+			    ret = func(session, cfg));
 			if (WT_META_TRACKING(session))
 				WT_TRET(
 				    __wt_meta_track_handle_lock(session, 0));
diff --git a/src/schema/schema_worker.c b/src/schema/schema_worker.c
index 94eb3170175..3dfd068cf9c 100644
--- a/src/schema/schema_worker.c
+++ b/src/schema/schema_worker.c
@@ -57,7 +57,8 @@ __wt_schema_worker(WT_SESSION_IMPL *session,
 
 			WT_ERR(__wt_session_get_btree_ckpt(
 			    session, uri, cfg, open_flags));
-			ret = file_func(session, cfg);
+			WT_SAVE_DHANDLE(session,
+			    ret = file_func(session, cfg));
 			WT_TRET(__wt_session_release_btree(session));
 		}
 	} else if (WT_PREFIX_MATCH(uri, "colgroup:")) {
diff --git a/src/txn/txn_ckpt.c b/src/txn/txn_ckpt.c
index eae21d0b9f5..fb590e1a297 100644
--- a/src/txn/txn_ckpt.c
+++ b/src/txn/txn_ckpt.c
@@ -237,7 +237,6 @@ __checkpoint_data_source(WT_SESSION_IMPL *session, const char *cfg[])
 int
 __wt_checkpoint_list(WT_SESSION_IMPL *session, const char *cfg[])
 {
-	WT_DATA_HANDLE *saved_dhandle;
 	WT_DECL_RET;
 	const char *name;
 
@@ -253,7 +252,6 @@ __wt_checkpoint_list(WT_SESSION_IMPL *session, const char *cfg[])
 
 	/* Not strictly necessary, but cleaner to clear the current handle. */
 	name = session->dhandle->name;
-	saved_dhandle = session->dhandle;
 	session->dhandle = NULL;
 
 	/* Record busy file names, we'll deal with them in the checkpoint. */
@@ -264,8 +262,7 @@ __wt_checkpoint_list(WT_SESSION_IMPL *session, const char *cfg[])
 		WT_ERR(__wt_strdup(session, name,
 		    &session->ckpt_handle[session->ckpt_handle_next++].name));
 
-err:	session->dhandle = saved_dhandle;
-	return (ret);
+err:	return (ret);
 }
 
 /*