X-Git-Url: http://git.tuebingen.mpg.de/?a=blobdiff_plain;f=dss.c;h=bb71bc4cef5a86033d94422e0d6cbf32043bb9df;hb=360bcc95d588232d8c81e028464d9e23b356a193;hp=c0597f3af32e4586d6fbb98f78aea9b59f338aff;hpb=723146898de138324dd6e421af05fd61c6cda848;p=dss.git

diff --git a/dss.c b/dss.c
index c0597f3..bb71bc4 100644
--- a/dss.c
+++ b/dss.c
@@ -185,8 +185,8 @@ static int next_snapshot_is_due(void)
 		goto out;
 	}
 
-	tv_divide(wanted, &diff, &tmp); /* sleep time betweeen two snapshots */
-	diff.tv_sec = s->completion_time; /* completion time of the the latest snaphot */
+	tv_divide(wanted, &diff, &tmp); /* sleep time between two snapshots */
+	diff.tv_sec = s->completion_time; /* completion time of the latest snapshot */
 	diff.tv_usec = 0;
 	tv_add(&diff, &tmp, &next_snapshot_time);
 	ret = (tv_diff(&now, &next_snapshot_time, &diff) < 0)? 0 : 1;
@@ -218,11 +218,13 @@ static int pre_create_hook(void)
 	return ret;
 }
 
-static int pre_remove_hook(struct snapshot *s, char *why)
+static int pre_remove_hook(struct snapshot *s, const char *why)
 {
 	int ret, fds[3] = {0, 0, 0};
 	char *cmd;
 
+	if (!s)
+		return 0;
 	DSS_DEBUG_LOG("%s snapshot %s\n", why, s->name);
 	assert(snapshot_removal_status == HS_READY);
 	assert(remove_pid == 0);
@@ -277,12 +279,46 @@ static int snapshot_is_being_created(struct snapshot *s)
 	return s->creation_time == current_snapshot_creation_time;
 }
 
+static struct snapshot *find_orphaned_snapshot(struct snapshot_list *sl)
+{
+	struct snapshot *s;
+	int i;
+
+	DSS_DEBUG_LOG("looking for orphaned snapshots\n");
+	FOR_EACH_SNAPSHOT(s, i, sl) {
+		if (snapshot_is_being_created(s))
+			continue;
+		/*
+		 * We know that no rm is currently running, so if s is marked
+		 * as being deleted, a previously started rm must have failed.
+		 */
+		if (s->flags & SS_BEING_DELETED)
+			return s;
+
+		if (s->flags & SS_COMPLETE) /* good snapshot */
+			continue;
+		/*
+		 * This snapshot is incomplete and it is not the snapshot
+		 * currently being created. However, we must not remove it if
+		 * rsync is about to be restarted. As only the newest snapshot
+		 * can be restarted, this snapshot is orphaned if it is not the
+		 * newest snapshot or if we are not about to restart rsync.
+		 */
+		if (get_newest_snapshot(sl) != s)
+			return s;
+		if (snapshot_creation_status != HS_NEEDS_RESTART)
+			return s;
+	}
+	/* no orphaned snapshots */
+	return NULL;
+}
+
 /*
  * return: 0: no redundant snapshots, 1: rm process started, negative: error
  */
-static int remove_redundant_snapshot(struct snapshot_list *sl)
+static struct snapshot *find_redundant_snapshot(struct snapshot_list *sl)
 {
-	int ret, i, interval;
+	int i, interval;
 	struct snapshot *s;
 	unsigned missing = 0;
 
@@ -329,20 +365,14 @@ static int remove_redundant_snapshot(struct snapshot_list *sl)
 			prev = s;
 		}
 		assert(victim);
-		if (conf.dry_run_given) {
-			dss_msg("%s would be removed (interval = %i)\n",
-				victim->name, victim->interval);
-			continue;
-		}
-		ret = pre_remove_hook(victim, "redundant");
-		return ret < 0? ret : 1;
+		return victim;
 	}
-	return 0;
+	return NULL;
 }
 
-static int remove_outdated_snapshot(struct snapshot_list *sl)
+static struct snapshot *find_outdated_snapshot(struct snapshot_list *sl)
 {
-	int i, ret;
+	int i;
 	struct snapshot *s;
 
 	DSS_DEBUG_LOG("looking for snapshots belonging to intervals greater than %d\n",
@@ -352,29 +382,21 @@ static int remove_outdated_snapshot(struct snapshot_list *sl)
 			continue;
 		if (s->interval <= conf.num_intervals_arg)
 			continue;
-		if (conf.dry_run_given) {
-			dss_msg("%s would be removed (interval = %i)\n",
-				s->name, s->interval);
-			continue;
-		}
-		ret = pre_remove_hook(s, "outdated");
-		if (ret < 0)
-			return ret;
-		return 1;
+		return s;
 	}
-	return 0;
+	return NULL;
 }
 
-static int remove_oldest_snapshot(struct snapshot_list *sl)
+struct snapshot *find_oldest_removable_snapshot(struct snapshot_list *sl)
 {
 	struct snapshot *s = get_oldest_snapshot(sl);
 
 	if (!s) /* no snapshot found */
-		return 0;
+		return NULL;
 	DSS_INFO_LOG("oldest snapshot: %s\n", s->name);
 	if (snapshot_is_being_created(s))
-		return 0;
-	return pre_remove_hook(s, "oldest");
+		return NULL;
+	return s;
 }
 
 static int rename_incomplete_snapshot(int64_t start)
@@ -400,7 +422,9 @@ static int try_to_free_disk_space(int low_disk_space)
 {
 	int ret;
 	struct snapshot_list sl;
+	struct snapshot *victim;
 	struct timeval now;
+	const char *why;
 
 	gettimeofday(&now, NULL);
 	if (tv_diff(&next_removal_check, &now, NULL) > 0)
@@ -408,22 +432,31 @@ static int try_to_free_disk_space(int low_disk_space)
 	if (!low_disk_space && conf.keep_redundant_given)
 		return 0;
 	dss_get_snapshot_list(&sl);
-	ret = remove_outdated_snapshot(&sl);
-	if (ret) /* error, or we are removing something */
-		goto out;
-	/* no outdated snapshot */
-	ret = remove_redundant_snapshot(&sl);
-	if (ret)
-		goto out;
+	why = "outdated";
+	victim = find_outdated_snapshot(&sl);
+	if (victim)
+		goto remove;
+	why = "redundant";
+	victim = find_redundant_snapshot(&sl);
+	if (victim)
+		goto remove;
+	/* try harder only if disk space is low */
 	ret = 0;
 	if (!low_disk_space)
 		goto out;
-	DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
-	ret = remove_oldest_snapshot(&sl);
-	if (ret)
+	why = "orphaned";
+	victim = find_orphaned_snapshot(&sl);
+	if (victim)
 		goto out;
+	DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
+	victim = find_oldest_removable_snapshot(&sl);
+	if (victim)
+		goto remove;
 	DSS_CRIT_LOG("uhuhu: not enough disk space for a single snapshot\n");
 	ret = -ERRNO_TO_DSS_ERROR(ENOSPC);
+	goto out;
+remove:
+	ret = pre_remove_hook(victim, why);
 out:
 	free_snapshot_list(&sl);
 	return ret;
@@ -637,7 +670,12 @@ static int handle_rsync_exit(int status)
 		goto out;
 	}
 	es = WEXITSTATUS(status);
-	if (es == 13) {	/* Errors with program diagnostics */
+	/*
+	 * Restart rsync on non-fatal errors:
+	 * 12: Error in rsync protocol data stream
+	 * 13: Errors with program diagnostics
+	 */
+	if (es == 12 || es == 13) {
 		DSS_WARNING_LOG("rsync process %d returned %d -- restarting\n",
 			(int)create_pid, es);
 		snapshot_creation_status = HS_NEEDS_RESTART;
@@ -1059,26 +1097,35 @@ static int com_prune(void)
 {
 	int ret;
 	struct snapshot_list sl;
+	struct snapshot *victim;
 	struct disk_space ds;
+	const char *why;
 
 	ret = get_disk_space(".", &ds);
 	if (ret < 0)
 		return ret;
 	log_disk_space(&ds);
 	dss_get_snapshot_list(&sl);
-	ret = remove_outdated_snapshot(&sl);
-	if (ret < 0)
-		goto out;
-	if (ret > 0)
+	why = "outdated";
+	victim = find_outdated_snapshot(&sl);
+	if (victim)
 		goto rm;
-	ret = remove_redundant_snapshot(&sl);
-	if (ret < 0)
-		goto out;
-	if (ret > 0)
+	why = "redundant";
+	victim = find_redundant_snapshot(&sl);
+	if (victim)
 		goto rm;
 	ret = 0;
 	goto out;
 rm:
+	if (conf.dry_run_given) {
+		dss_msg("%s snapshot %s (interval = %i)\n",
+			why, victim->name, victim->interval);
+		ret = 0;
+		goto out;
+	}
+	ret = pre_remove_hook(victim, why);
+	if (ret < 0)
+		goto out;
 	if (snapshot_removal_status == HS_PRE_RUNNING) {
 		ret = wait_for_remove_process();
 		if (ret < 0)