Merge branch 't/recycling'
[dss.git] / dss.c
diff --git a/dss.c b/dss.c
index e32e7e20a1efcad97f213b7da6212bb881ccc248..3508d38d798c1af448398c2de1d0b438a61bb4e4 100644 (file)
--- a/dss.c
+++ b/dss.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2008-2009 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2008-2010 Andre Noll <maan@systemlinux.org>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
@@ -64,7 +64,106 @@ enum hook_status snapshot_removal_status;
 
 
 DEFINE_DSS_ERRLIST;
+static const char const *hook_status_description[] = {HOOK_STATUS_ARRAY};
 
+/* may be called with ds == NULL. */
+static int disk_space_low(struct disk_space *ds)
+{
+       struct disk_space ds_struct;
+
+       if (!ds) {
+               int ret = get_disk_space(".", &ds_struct);
+               if (ret < 0)
+                       return ret;
+               ds = &ds_struct;
+       }
+       if (conf.min_free_mb_arg)
+               if (ds->free_mb < conf.min_free_mb_arg)
+                       return 1;
+       if (conf.min_free_percent_arg)
+               if (ds->percent_free < conf.min_free_percent_arg)
+                       return 1;
+       if (conf.min_free_percent_inodes_arg)
+               if (ds->percent_free_inodes < conf.min_free_percent_inodes_arg)
+                       return 1;
+       return 0;
+}
+
+static void dump_dss_config(const char *msg)
+{
+       const char dash[] = "-----------------------------";
+       int ret;
+       FILE *log = logfile? logfile : stderr;
+       struct disk_space ds;
+       int64_t now = get_current_time();
+
+       if (conf.loglevel_arg > INFO)
+               return;
+
+       fprintf(log, "%s <%s config> %s\n", dash, msg, dash);
+       fprintf(log, "\n*** disk space ***\n\n");
+       ret = get_disk_space(".", &ds);
+       if (ret >= 0) {
+               DSS_INFO_LOG("disk space low: %s\n", disk_space_low(&ds)?
+                       "yes" : "no");
+               log_disk_space(&ds);
+       } else
+               DSS_ERROR_LOG("can not get free disk space: %s\n",
+                       dss_strerror(-ret));
+
+       /* we continue on errors from get_disk_space */
+
+       fprintf(log, "\n*** command line and config file options ***\n\n");
+       cmdline_parser_dump(log, &conf);
+       fprintf(log, "\n*** internal state ***\n\n");
+       fprintf(log,
+               "pid: %d\n"
+               "logile: %s\n"
+               "snapshot_currently_being_removed: %s\n"
+               "path_to_last_complete_snapshot: %s\n"
+               "reference_snapshot: %s\n"
+               "snapshot_creation_status: %s\n"
+               "snapshot_removal_status: %s\n"
+               ,
+               (int) getpid(),
+               logfile? conf.logfile_arg : "stderr",
+               snapshot_currently_being_removed?
+                       snapshot_currently_being_removed->name : "(none)",
+               path_to_last_complete_snapshot?
+                       path_to_last_complete_snapshot : "(none)",
+               name_of_reference_snapshot?
+                       name_of_reference_snapshot : "(none)",
+               hook_status_description[snapshot_creation_status],
+               hook_status_description[snapshot_removal_status]
+       );
+       if (create_pid != 0)
+               fprintf(log,
+                       "create_pid: %" PRId32 "\n"
+                       "create process is %sstopped\n"
+                       ,
+                       create_pid,
+                       create_process_stopped? "" : "not "
+               );
+       if (remove_pid != 0)
+               fprintf(log, "remove_pid: %" PRId32 "\n", remove_pid);
+       if (next_snapshot_time != 0)
+               fprintf(log, "next snapshot due in %" PRId64 " seconds\n",
+                       next_snapshot_time - now);
+       if (current_snapshot_creation_time != 0)
+               fprintf(log, "current_snapshot_creation_time: %"
+                       PRId64 " (%" PRId64 " seconds ago)\n",
+                       current_snapshot_creation_time,
+                       now - current_snapshot_creation_time
+               );
+       if (next_removal_check.tv_sec != 0) {
+               fprintf(log, "next removal check: %llu (%llu seconds ago)\n",
+                       (long long unsigned)next_removal_check.tv_sec,
+                       now - (long long unsigned)next_removal_check.tv_sec
+               );
+
+       }
+       fprintf(log, "%s </%s config> %s\n", dash, msg, dash);
+}
 
 /* a litte cpp magic helps to DRY */
 #define COMMANDS \
@@ -127,25 +226,6 @@ static __printf_1_2 void dss_msg(const char* fmt,...)
        va_end(argp);
 }
 
-static int disk_space_low(void)
-{
-       struct disk_space ds;
-       int ret = get_disk_space(".", &ds);
-
-       if (ret < 0)
-               return ret;
-       if (conf.min_free_mb_arg)
-               if (ds.free_mb < conf.min_free_mb_arg)
-                       return 1;
-       if (conf.min_free_percent_arg)
-               if (ds.percent_free < conf.min_free_percent_arg)
-                       return 1;
-       if (conf.min_free_percent_inodes_arg)
-               if (ds.percent_free_inodes < conf.min_free_percent_inodes_arg)
-                       return 1;
-       return 0;
-}
-
 static void dss_get_snapshot_list(struct snapshot_list *sl)
 {
        get_snapshot_list(sl, conf.unit_interval_arg, conf.num_intervals_arg);
@@ -441,7 +521,7 @@ static int try_to_free_disk_space(void)
        const char *why;
        int low_disk_space;
 
-       ret = disk_space_low();
+       ret = disk_space_low(NULL);
        if (ret < 0)
                return ret;
        low_disk_space = ret;
@@ -903,24 +983,16 @@ static int change_to_dest_dir(void)
        return dss_chdir(conf.dest_dir_arg);
 }
 
-static void dump_dss_config(const char *msg)
-{
-       if (conf.loglevel_arg > INFO)
-               return;
-       DSS_INFO_LOG("%s\n", msg);
-       cmdline_parser_dump(logfile? logfile : stderr, &conf);
-}
-
 static int handle_sighup(void)
 {
        int ret;
 
        DSS_NOTICE_LOG("SIGHUP, re-reading config\n");
-       dump_dss_config("current config");
+       dump_dss_config("old");
        ret = parse_config_file(1);
        if (ret < 0)
                return ret;
-       dump_dss_config("new config");
+       dump_dss_config("reloaded");
        invalidate_next_snapshot_time();
        return change_to_dest_dir();
 }
@@ -971,22 +1043,48 @@ static int use_rsync_locally(char *logname)
 static int rename_resume_snap(int64_t creation_time)
 {
        struct snapshot_list sl = {.num_snapshots = 0};
-       struct snapshot *s;
+       struct snapshot *s = NULL;
        char *new_name = incomplete_name(creation_time);
        int ret;
+       const char *why;
 
        ret = 0;
        if (conf.no_resume_given)
                goto out;
        dss_get_snapshot_list(&sl);
+       /*
+        * Snapshot recycling: We first look at the newest snapshot. If this
+        * snapshot happens to be incomplete, the last rsync process was
+        * aborted and we reuse this one. Otherwise we look at snapshots which
+        * could be removed (outdated and redundant snapshots) as candidates
+        * for recycling. If no outdated/redundant snapshot exists, we check if
+        * there is an orphaned snapshot, which likely is useless anyway.
+        *
+        * Only if no existing snapshot is suitable for recycling, we bite the
+        * bullet and create a new one.
+        */
        s = get_newest_snapshot(&sl);
-       if (!s)
+       if (!s) /* no snapshots at all */
                goto out;
-       if ((s->flags & SS_COMPLETE) != 0) /* complete */
+       /* re-use last snapshot if it is incomplete */
+       why = "aborted";
+       if ((s->flags & SS_COMPLETE) == 0)
                goto out;
-       DSS_INFO_LOG("resuming: reusing %s as destination dir\n", s->name);
-       ret = dss_rename(s->name, new_name);
+       why = "outdated";
+       s = find_outdated_snapshot(&sl);
+       if (s)
+               goto out;
+       why = "redundant";
+       s = find_redundant_snapshot(&sl);
+       if (s)
+               goto out;
+       why = "orphaned";
+       s = find_orphaned_snapshot(&sl);
 out:
+       if (s) {
+               DSS_INFO_LOG("reusing %s snapshot %s\n", why, s->name);
+               ret = dss_rename(s->name, new_name);
+       }
        if (ret >= 0)
                DSS_NOTICE_LOG("creating new snapshot %s\n", new_name);
        free(new_name);
@@ -1354,10 +1452,10 @@ int main(int argc, char **argv)
        }
        if (conf.daemon_given)
                daemon_init();
-       dump_dss_config("dss configuration");
        ret = change_to_dest_dir();
        if (ret < 0)
                goto out;
+       dump_dss_config("startup");
        ret = setup_signal_handling();
        if (ret < 0)
                goto out;