[sheepdog] [PATCH 1/2] migrate: update config file with a new format version

[MORITA Kazutaka]

Signed-off-by: MORITA Kazutaka <morita.kazutaka at lab.ntt.co.jp>
---
 sheep/config.c  |   10 ++++++++++
 sheep/migrate.c |   30 +++++++++++++++++++-----------
 2 files changed, 29 insertions(+), 11 deletions(-)

diff --git a/sheep/config.c b/sheep/config.c
index b2e9f58..e38bea0 100644
--- a/sheep/config.c
+++ b/sheep/config.c
@@ -96,6 +96,16 @@ int init_config_path(const char *base_path)
 		if (sys->upgrade) {
 			/* upgrade sheep store */
 			ret = sd_migrate_store(config.version, SD_FORMAT_VERSION);
+			if (ret == 0) {
+				/* reload config file */
+				ret = xpread(fd, &config, sizeof(config), 0);
+				if (ret != sizeof(config)) {
+					eprintf("failed to reload config file,"
+						" %m\n");
+					ret = -1;
+				} else
+					ret = 0;
+			}
 			goto out;
 		}
 
diff --git a/sheep/migrate.c b/sheep/migrate.c
index bbad644..d253ead 100644
--- a/sheep/migrate.c
+++ b/sheep/migrate.c
@@ -81,21 +81,29 @@ static int migrate_from_v0_to_v1(void)
 		return ret;
 	}
 
+	config.version = 1;
+	ret = xpwrite(fd, &config, sizeof(config), 0);
+	if (ret != sizeof(config)) {
+		eprintf("failed to write config data, %m\n");
+		close(fd);
+		return -1;
+	}
+
+	/* 0.5.1 could wrongly extend the config file, so truncate it here */
+	ret = ftruncate(fd, sizeof(config));
+	if (ret != 0) {
+		eprintf("failed to truncate config data, %m\n");
+		close(fd);
+		return -1;
+	}
+
+	close(fd);
+
 	/* If the config file contains a space field, the store layout
 	 * is compatible with v1.  In this case, what we need to do is
 	 * only adding version number to the config file. */
-	if (config.space > 0) {
-		config.version = 1;
-		ret = xwrite(fd, &config, sizeof(config));
-		if (ret != sizeof(config)) {
-			eprintf("failed to write config data, %m\n");
-			close(fd);
-			return -1;
-		}
-
-		close(fd);
+	if (config.space > 0)
 		return 0;
-	}
 
 	/* upgrade epoch log */
 	le = get_latest_epoch();
-- 
1.7.2.5