dss.c: Remove pointless comment for main().

[dss.git] / dss.c

diff --git a/dss.c b/dss.c
index 813d73dc11204a2a4a6989c89e23f469db049680..bdbdd043ef8c4651bf921a72050526b84c968a6d 100644 (file)
--- a/dss.c
+++ b/dss.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2008-2011 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2008-2011 Andre Noll <maan@tuebingen.mpg.de>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
@@ -45,6 +45,8 @@ static int signal_pipe;
 static pid_t create_pid;
 /** Whether the pre-create-hook/rsync/post-create-hook is currently stopped. */
 static int create_process_stopped;
+/** How many times in a row the rsync command failed. */
+static int num_consecutive_rsync_errors;
 /** Process id of current pre-remove/rm/post-remove process. */
 static pid_t remove_pid;
 /** When the next snapshot is due. */
@@ -125,6 +127,7 @@ static void dump_dss_config(const char *msg)
                "reference_snapshot: %s\n"
                "snapshot_creation_status: %s\n"
                "snapshot_removal_status: %s\n"
+               "num_consecutive_rsync_errors: %d\n"
                ,
                (int) getpid(),
                logfile? conf.logfile_arg : "stderr",
@@ -135,7 +138,8 @@ static void dump_dss_config(const char *msg)
                name_of_reference_snapshot?
                        name_of_reference_snapshot : "(none)",
                hook_status_description[snapshot_creation_status],
-               hook_status_description[snapshot_removal_status]
+               hook_status_description[snapshot_removal_status],
+               num_consecutive_rsync_errors
        );
        if (create_pid != 0)
                fprintf(log,
@@ -531,17 +535,25 @@ static struct snapshot *find_outdated_snapshot(struct snapshot_list *sl)
 
 static struct snapshot *find_oldest_removable_snapshot(struct snapshot_list *sl)
 {
-       int i;
-       struct snapshot *s;
+       int i, num_complete;
+       struct snapshot *s, *ref = NULL;
+
+       num_complete = num_complete_snapshots(sl);
+       if (num_complete <= conf.min_complete_arg)
+               return NULL;
        FOR_EACH_SNAPSHOT(s, i, sl) {
                if (snapshot_is_being_created(s))
                        continue;
-               if (is_reference_snapshot(s))
+               if (is_reference_snapshot(s)) { /* avoid this one */
+                       ref = s;
                        continue;
+               }
                DSS_INFO_LOG(("oldest removable snapshot: %s\n", s->name));
                return s;
        }
-       return NULL;
+       assert(ref);
+       DSS_WARNING_LOG(("removing reference snapshot %s\n", ref->name));
+       return ref;
 }
 
 static int rename_incomplete_snapshot(int64_t start)
@@ -594,9 +606,18 @@ static int try_to_free_disk_space(void)
                if (next_snapshot_is_due())
                        return 0;
        }
+       /*
+        * Idle and --keep_redundant not given, or low disk space. Look at
+        * existing snapshots.
+        */
        dss_get_snapshot_list(&sl);
        ret = 0;
-       if (!low_disk_space && sl.num_snapshots <= 1)
+       /*
+        * Don't remove anything if there is free space and we have fewer
+        * snapshots than configured, plus one. This way there is always one
+        * snapshot that can be recycled.
+        */
+       if (!low_disk_space && sl.num_snapshots <= 1 << conf.num_intervals_arg)
                goto out;
        why = "outdated";
        victim = find_outdated_snapshot(&sl);
@@ -606,13 +627,13 @@ static int try_to_free_disk_space(void)
        victim = find_redundant_snapshot(&sl);
        if (victim)
                goto remove;
-       /* try harder only if disk space is low */
-       if (!low_disk_space)
-               goto out;
        why = "orphaned";
        victim = find_orphaned_snapshot(&sl);
        if (victim)
                goto remove;
+       /* try harder only if disk space is low */
+       if (!low_disk_space)
+               goto out;
        DSS_WARNING_LOG(("disk space low and nothing obvious to remove\n"));
        victim = find_oldest_removable_snapshot(&sl);
        if (victim)
@@ -836,23 +857,23 @@ static int handle_rsync_exit(int status)
        es = WEXITSTATUS(status);
        /*
         * Restart rsync on non-fatal errors:
-        * 12: Error in rsync protocol data stream
-        * 13: Errors with program diagnostics
+        * 24: Partial transfer due to vanished source files
         */
-       if (es == 12 || es == 13) {
-               DSS_WARNING_LOG(("rsync process %d returned %d -- restarting\n",
-                       (int)create_pid, es));
+       if (es != 0 && es != 24) {
+               DSS_WARNING_LOG(("rsync exit code %d, error count %d\n",
+                       es, ++num_consecutive_rsync_errors));
+               if (num_consecutive_rsync_errors > conf.max_rsync_errors_arg) {
+                       ret = -E_TOO_MANY_RSYNC_ERRORS;
+                       snapshot_creation_status = HS_READY;
+                       goto out;
+               }
+               DSS_WARNING_LOG(("restarting rsync process\n"));
                snapshot_creation_status = HS_NEEDS_RESTART;
                next_snapshot_time = get_current_time() + 60;
                ret = 1;
                goto out;
        }
-       if (es != 0 && es != 23 && es != 24) {
-               DSS_ERROR_LOG(("rsync process %d returned %d\n", (int)create_pid, es));
-               ret = -E_BAD_EXIT_CODE;
-               snapshot_creation_status = HS_READY;
-               goto out;
-       }
+       num_consecutive_rsync_errors = 0;
        ret = rename_incomplete_snapshot(current_snapshot_creation_time);
        if (ret < 0)
                goto out;
@@ -1038,6 +1059,13 @@ static int handle_sighup(void)
        return change_to_dest_dir();
 }
 
+static void kill_children(void)
+{
+       restart_create_process();
+       dss_kill(create_pid, SIGTERM, NULL);
+       dss_kill(remove_pid, SIGTERM, NULL);
+}
+
 static int handle_signal(void)
 {
        int sig, ret = next_signal();
@@ -1048,9 +1076,7 @@ static int handle_signal(void)
        switch (sig) {
        case SIGINT:
        case SIGTERM:
-               restart_create_process();
-               dss_kill(create_pid, SIGTERM, NULL);
-               dss_kill(remove_pid, SIGTERM, NULL);
+               kill_children();
                ret = -E_SIGNAL;
                break;
        case SIGHUP:
@@ -1319,6 +1345,7 @@ static int com_run(void)
        ret = select_loop();
        if (ret >= 0) /* impossible */
                ret = -E_BUG;
+       kill_children();
        exit_hook(ret);
        return ret;
 }
@@ -1442,7 +1469,7 @@ static int com_ls(void)
                if (s->flags & SS_COMPLETE)
                        d = (s->completion_time - s->creation_time) / 60;
                dss_msg("%u\t%s\t%3" PRId64 ":%02" PRId64 "\n", s->interval, s->name, d/60, d%60);
-       };
+       }
        free_snapshot_list(&sl);
        return 1;
 }
@@ -1462,12 +1489,6 @@ static int setup_signal_handling(void)
        return install_sighandler(SIGCHLD);
 }
 
-/**
- * The main function of dss.
- *
- * \param argc Usual argument count.
- * \param argv Usual argument vector.
- */
 int main(int argc, char **argv)
 {
        int ret;
@@ -1506,6 +1527,7 @@ int main(int argc, char **argv)
        if (ret < 0)
                goto out;
        ret = call_command_handler();
+       signal_shutdown();
 out:
        if (ret < 0)
                DSS_EMERG_LOG(("%s\n", dss_strerror(-ret)));