From 825ce5330d5ee68f90fe9a442c44db3e20e2d859 Mon Sep 17 00:00:00 2001
From: Fabian Keil <fk@fabiankeil.de>
Date: Mon, 27 Apr 2015 19:53:30 +0200
Subject: [PATCH 254/310] ggate[cd]: Improve BIO_FLUSH support (XXX)

Let ggated transform BIO_FLUSH requests into fsync() calls.

Obtained from: ElectroBSD
---
 sbin/ggate/ggatec/ggatec.c |  5 ++++-
 sbin/ggate/ggated/ggated.c | 21 +++++++++++++++------
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/sbin/ggate/ggatec/ggatec.c b/sbin/ggate/ggatec/ggatec.c
index 78daab7d50b1..19b90081d772 100644
--- a/sbin/ggate/ggatec/ggatec.c
+++ b/sbin/ggate/ggatec/ggatec.c
@@ -163,7 +163,9 @@ send_thread(void *arg __unused)
 			hdr.gh_cmd = GGATE_CMD_WRITE;
 			break;
 		case BIO_FLUSH:
+			g_gate_log(LOG_DEBUG, "FLUSH request");
 			hdr.gh_cmd = GGATE_CMD_FLUSH;
+			assert(ggio.gctl_length == 0);
 			break;
 		default:
 			g_gate_log(LOG_NOTICE, "Unknown gctl_cmd: %i",
@@ -267,7 +269,8 @@ recv_thread(void *arg __unused)
 			}
 		}
 		if (ggio.gctl_cmd != GGATE_CMD_READ &&
-		    ggio.gctl_cmd != GGATE_CMD_WRITE) {
+		    ggio.gctl_cmd != GGATE_CMD_WRITE &&
+		    ggio.gctl_cmd != GGATE_CMD_FLUSH) {
 			g_gate_xlog("Unexpected GGATE_CMD: %d", ggio.gctl_cmd);
 		}
 
diff --git a/sbin/ggate/ggated/ggated.c b/sbin/ggate/ggated/ggated.c
index d5d8d564253c..820984add062 100644
--- a/sbin/ggate/ggated/ggated.c
+++ b/sbin/ggate/ggated/ggated.c
@@ -672,8 +672,10 @@ recv_thread(void *arg)
 		 * Reject requests that violate assertions in disk_thread().
 		 */
 		if (req->r_cmd != GGATE_CMD_READ &&
-		    req->r_cmd != GGATE_CMD_WRITE) {
-			g_gate_xlog("Request contains invalid command.");
+		    req->r_cmd != GGATE_CMD_WRITE &&
+		    req->r_cmd != GGATE_CMD_FLUSH) {
+			g_gate_xlog("Request contains invalid command: %d",
+			    req->r_cmd);
 		}
 		if (req->r_offset + req->r_length >
 		    (uintmax_t)conn->c_mediasize) {
@@ -696,9 +698,10 @@ recv_thread(void *arg)
 		}
 
 		/*
-		 * Allocate memory for data.
+		 * Allocate memory for data, except when flushing.
 		 */
-		req->r_data = malloc_waitok(req->r_length);
+		req->r_data = req->r_cmd != GGATE_CMD_FLUSH ?
+                    malloc_waitok(req->r_length) : NULL;
 
 		/*
 		 * Receive data to write for WRITE request.
@@ -758,6 +761,9 @@ disk_thread(void *arg)
 		/*
 		 * Check the request.
 		 */
+		assert(req->r_cmd == GGATE_CMD_READ ||
+		    req->r_cmd == GGATE_CMD_WRITE ||
+		    req->r_cmd == GGATE_CMD_FLUSH);
 		assert(req->r_offset + req->r_length <= (uintmax_t)conn->c_mediasize);
 		assert((req->r_offset % conn->c_sectorsize) == 0);
 		assert((req->r_length % conn->c_sectorsize) == 0);
@@ -782,9 +788,12 @@ disk_thread(void *arg)
 			req->r_data = NULL;
 			break;
 		case GGATE_CMD_FLUSH:
-			data = fsync(fd);
-			if (data != 0)
+			g_gate_log(LOG_DEBUG, "Flushing");
+			if (fsync(fd)) {
 				req->r_error = errno;
+				g_gate_log(LOG_ERR, "Flushing failed: %s",
+				    strerror(errno));
+			}
 			break;
 		default:
 			g_gate_log(LOG_DEBUG, "Unsupported request: %i", req->r_cmd);
-- 
2.37.1