From fd7b409d26b1dcef3ff0ca6bc50b736fad6184b2 Mon Sep 17 00:00:00 2001
From: Nalin Dahyabhai <nalin@dahyabhai.net>
Date: Mon, 22 Jul 2013 15:56:08 -0400
Subject: Notice when we fail to write lock

When we fail to write-lock our cache, cancel our update attempt.  We'll
fall out of sync with the real data, but for now at least, that's better
than completely hosing the cache by updating it without the lock.
---
 src/back-shr.c | 51 +++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 45 insertions(+), 6 deletions(-)

diff --git a/src/back-shr.c b/src/back-shr.c
index ade1336..5b7c6ec 100644
--- a/src/back-shr.c
+++ b/src/back-shr.c
@@ -594,7 +594,14 @@ backend_shr_startup(struct plugin_state *state,
 				     NULL,
 				     state->plugin_identity,
 				     0);
-	map_wrlock();
+	if (map_wrlock() != 0) {
+		slapi_log_error(SLAPI_LOG_PLUGIN,
+				state->plugin_desc->spd_id,
+				"failed to search under \"%s\" for "
+				"configuration: failed to acquire a lock\n",
+				state->plugin_base);
+		goto done_with_lock;
+	}
 	set_cbdata.state = state;
 	set_cbdata.pb = pb;
 	slapi_search_internal_callback_pb(pb, &set_cbdata,
@@ -602,6 +609,7 @@ backend_shr_startup(struct plugin_state *state,
 					  backend_set_config_entry_add_cb,
 					  NULL);
 	map_unlock();
+done_with_lock:
 	slapi_pblock_destroy(pb);
 }
 
@@ -1582,7 +1590,14 @@ backend_shr_add_cb(Slapi_PBlock *pb)
 	/* Add map entries which corresponded to this directory server
 	 * entry. */
 	wrap_inc_call_level();
-	map_wrlock();
+	if (map_wrlock() != 0) {
+		slapi_log_error(SLAPI_LOG_PLUGIN,
+				cbdata.state->plugin_desc->spd_id,
+				"error adding set entries corresponding to "
+				"\"%s\": failed to acquire a lock\n",
+				cbdata.ndn);
+		goto done_with_lock;
+	}
 	if (!map_data_foreach_map(cbdata.state, NULL,
 				  backend_shr_add_entry_cb, &cbdata)) {
 		slapi_log_error(SLAPI_LOG_PLUGIN,
@@ -1604,8 +1619,8 @@ backend_shr_add_cb(Slapi_PBlock *pb)
 
 	/* Update entries in maps which are affected by this entry. */
 	backend_shr_update_references(cbdata.state, pb, cbdata.e, NULL, NULL);
-
 	map_unlock();
+done_with_lock:
 	wrap_dec_call_level();
 	return 0;
 }
@@ -2009,7 +2024,14 @@ backend_shr_modify_cb(Slapi_PBlock *pb)
 	/* Modify map entries which corresponded to this directory server
 	 * entry. */
 	wrap_inc_call_level();
-	map_wrlock();
+	if (map_wrlock() != 0) {
+		slapi_log_error(SLAPI_LOG_PLUGIN,
+				cbdata.state->plugin_desc->spd_id,
+				"error modifying set entries corresponding to "
+				"\"%s\": failed to acquire a lock\n",
+				cbdata.ndn);
+		goto done_with_lock;
+	}
 	if (!map_data_foreach_map(cbdata.state, NULL,
 				  backend_shr_modify_entry_cb, &cbdata)) {
 		slapi_log_error(SLAPI_LOG_PLUGIN,
@@ -2059,6 +2081,7 @@ backend_shr_modify_cb(Slapi_PBlock *pb)
 		slapi_sdn_free(&sdn);
 	}
 	map_unlock();
+done_with_lock:
 	wrap_dec_call_level();
 	free(cbdata.modlist);
 	return 0;
@@ -2178,7 +2201,14 @@ backend_shr_modrdn_cb(Slapi_PBlock *pb)
 	/* Modify map entries which corresponded to this directory server
 	 * entry. */
 	wrap_inc_call_level();
-	map_wrlock();
+	if (map_wrlock() != 0) {
+		slapi_log_error(SLAPI_LOG_PLUGIN,
+				cbdata.state->plugin_desc->spd_id,
+				"error renaming map entries corresponding to "
+				"\"%s\": failed to acquire a lock\n",
+				cbdata.ndn_post);
+		goto done_with_lock;
+	}
 	if (!map_data_foreach_map(cbdata.state, NULL,
 				  backend_shr_modrdn_entry_cb, &cbdata)) {
 		slapi_log_error(SLAPI_LOG_PLUGIN,
@@ -2205,6 +2235,7 @@ backend_shr_modrdn_cb(Slapi_PBlock *pb)
 		backend_set_config_entry_add_cb(cbdata.e_post, &set_cbdata);
 	}
 	map_unlock();
+done_with_lock:
 	wrap_dec_call_level();
 	return 0;
 }
@@ -2305,7 +2336,14 @@ backend_shr_delete_cb(Slapi_PBlock *pb)
 	/* Remove map entries which corresponded to this directory server
 	 * entry. */
 	wrap_inc_call_level();
-	map_wrlock();
+	if (map_wrlock() != 0) {
+		slapi_log_error(SLAPI_LOG_PLUGIN,
+				cbdata.state->plugin_desc->spd_id,
+				"error removing entries corresponding to "
+				"\"%s\": failed to acquire a lock\n",
+				cbdata.ndn);
+		goto done_with_lock;
+	}
 	if (!map_data_foreach_map(cbdata.state, NULL,
 				  backend_shr_delete_entry_cb, &cbdata)) {
 		slapi_log_error(SLAPI_LOG_PLUGIN,
@@ -2324,6 +2362,7 @@ backend_shr_delete_cb(Slapi_PBlock *pb)
 	 * affected by this entry. */
 	backend_shr_update_references(cbdata.state, pb, cbdata.e, NULL, NULL);
 	map_unlock();
+done_with_lock:
 	wrap_dec_call_level();
 	return 0;
 }
-- 
cgit