X-Git-Url: http://git.tuebingen.mpg.de/?p=dss.git;a=blobdiff_plain;f=dss.c;h=217dfafd25c55741e564c0feb13c1ccfbad317d0;hp=b6a3d3e714059861ab1ae100933655b7e4e13c50;hb=HEAD;hpb=dd3f58c0bdf1e9f7bb86d09e6f7faf155d6b5310

diff --git a/dss.c b/dss.c
index b6a3d3e..0992ec6 100644
--- a/dss.c
+++ b/dss.c
@@ -81,7 +81,7 @@ static int64_t next_snapshot_time;
 static struct timeval next_removal_check;
 /** Creation time of the snapshot currently being created. */
 static int64_t current_snapshot_creation_time;
-/** The snapshot currently being removed. */
+/* Set by the pre-rm hook, cleared by handle_remove_exit(). */
 struct snapshot *snapshot_currently_being_removed;
 /** Needed by the post-create hook. */
 static char *path_to_last_complete_snapshot;
@@ -574,9 +574,6 @@ static int is_reference_snapshot(struct snapshot *s)
 	return strcmp(s->name, name_of_reference_snapshot)? 0 : 1;
 }
 
-/*
- * return: 0: no redundant snapshots, 1: rm process started, negative: error
- */
 static struct snapshot *find_redundant_snapshot(struct snapshot_list *sl)
 {
 	int i, interval;
@@ -654,6 +651,7 @@ static struct snapshot *find_oldest_removable_snapshot(struct snapshot_list *sl)
 	int i, num_complete;
 	struct snapshot *s, *ref = NULL;
 
+	DSS_DEBUG_LOG(("picking snapshot with earliest creation time\n"));
 	num_complete = num_complete_snapshots(sl);
 	if (num_complete <= OPT_UINT32_VAL(DSS, MIN_COMPLETE))
 		return NULL;
@@ -664,7 +662,6 @@ static struct snapshot *find_oldest_removable_snapshot(struct snapshot_list *sl)
 			ref = s;
 			continue;
 		}
-		DSS_INFO_LOG(("oldest removable snapshot: %s\n", s->name));
 		return s;
 	}
 	assert(ref);
@@ -672,6 +669,50 @@ static struct snapshot *find_oldest_removable_snapshot(struct snapshot_list *sl)
 	return ref;
 }
 
+/* returns NULL <==> *reason is set to NULL */
+static struct snapshot *find_removable_snapshot(struct snapshot_list *sl,
+		bool try_hard, char **reason)
+{
+	struct snapshot *victim;
+
+	/*
+	 * 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 (!try_hard && sl->num_snapshots <=
+			1 << OPT_UINT32_VAL(DSS, NUM_INTERVALS))
+		goto nope;
+	victim = find_orphaned_snapshot(sl);
+	if (victim) {
+		*reason = make_message("orphaned");
+		return victim;
+	}
+	victim = find_outdated_snapshot(sl);
+	if (victim) {
+		*reason = make_message("outdated");
+		return victim;
+	}
+	if (!OPT_GIVEN(DSS, KEEP_REDUNDANT)) {
+		victim = find_redundant_snapshot(sl);
+		if (victim) {
+			*reason = make_message("redundant");
+			return victim;
+		}
+	}
+	if (!try_hard)
+		goto nope;
+	DSS_WARNING_LOG(("nothing obvious to remove\n"));
+	victim = find_oldest_removable_snapshot(sl);
+	if (victim) {
+		*reason = make_message("oldest");
+		return victim;
+	}
+nope:
+	*reason = NULL;
+	return NULL;
+}
+
 static int rename_incomplete_snapshot(int64_t start)
 {
 	char *old_name;
@@ -704,7 +745,7 @@ static int try_to_free_disk_space(void)
 	struct snapshot_list sl;
 	struct snapshot *victim;
 	struct timeval now;
-	const char *why;
+	char *why;
 	int low_disk_space;
 
 	ret = disk_space_low(NULL);
@@ -715,55 +756,25 @@ static int try_to_free_disk_space(void)
 	if (tv_diff(&next_removal_check, &now, NULL) > 0)
 		return 0;
 	if (!low_disk_space) {
-		if (OPT_GIVEN(DSS, KEEP_REDUNDANT))
-			return 0;
 		if (snapshot_creation_status != HS_READY)
 			return 0;
 		if (next_snapshot_is_due())
 			return 0;
 	}
-	/*
-	 * Idle and --keep_redundant not given, or low disk space. Look at
-	 * existing snapshots.
-	 */
+	/* Idle or low disk space, look at existing snapshots. */
 	dss_get_snapshot_list(&sl);
-	ret = 0;
-	/*
-	 * 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 << OPT_UINT32_VAL(DSS, NUM_INTERVALS))
-		goto out;
-	why = "outdated";
-	victim = find_outdated_snapshot(&sl);
-	if (victim)
-		goto remove;
-	why = "redundant";
-	victim = find_redundant_snapshot(&sl);
-	if (victim)
-		goto remove;
-	why = "orphaned";
-	victim = find_orphaned_snapshot(&sl);
+	victim = find_removable_snapshot(&sl, low_disk_space, &why);
+	if (victim) {
+		pre_remove_hook(victim, why);
+		free(why);
+	}
+	free_snapshot_list(&sl);
 	if (victim)
-		goto remove;
-	/* try harder only if disk space is low */
+		return 1;
 	if (!low_disk_space)
-		goto out;
-	DSS_WARNING_LOG(("disk space low and nothing obvious to remove\n"));
-	why = "oldest";
-	victim = find_oldest_removable_snapshot(&sl);
-	if (victim)
-		goto remove;
+		return 0;
 	DSS_CRIT_LOG(("uhuhu: disk space low and nothing to remove\n"));
-	ret = -ERRNO_TO_DSS_ERROR(ENOSPC);
-	goto out;
-remove:
-	pre_remove_hook(victim, why);
-out:
-	free_snapshot_list(&sl);
-	return ret;
+	return -ERRNO_TO_DSS_ERROR(ENOSPC);
 }
 
 static void post_create_hook(void)
@@ -1111,7 +1122,6 @@ static int change_to_dest_dir(void)
 
 static int check_config(void)
 {
-	int ret;
 	uint32_t unit_interval = OPT_UINT32_VAL(DSS, UNIT_INTERVAL);
 	uint32_t num_intervals = OPT_UINT32_VAL(DSS, NUM_INTERVALS);
 
@@ -1136,9 +1146,6 @@ static int check_config(void)
 			DSS_ERROR_LOG(("--dest-dir required\n"));
 			return -E_SYNTAX;
 		}
-		ret = change_to_dest_dir();
-		if (ret < 0)
-			return ret;
 	}
 	DSS_DEBUG_LOG(("number of intervals: %i\n", num_intervals));
 	return 1;
@@ -1252,8 +1259,6 @@ close_fd:
 		close(fd);
 out:
 	free(config_file);
-	if (ret < 0)
-		DSS_EMERG_LOG(("%s\n", dss_strerror(-ret)));
 	return ret;
 }
 
@@ -1447,7 +1452,7 @@ static void create_rsync_argv(char ***argv, int64_t *num)
 					OPT_STRING_VAL(DSS, REMOTE_USER) : logname,
 				OPT_STRING_VAL(DSS, REMOTE_HOST),
 				lls_string_val(j, OPT_RESULT(DSS, SOURCE_DIR)),
-				N == 1? "/" : ""
+				OPT_GIVEN(DSS, SOURCE_DIR) == 1? "/" : ""
 			);
 		}
 	}
@@ -1570,7 +1575,7 @@ static void exit_hook(int exit_code)
 {
 	pid_t pid;
 	char **argv, *tmp = dss_strdup(OPT_STRING_VAL(DSS, EXIT_HOOK));
-	unsigned n = split_args(tmp, &argv, " \t");
+	unsigned n = split_args(tmp, &argv);
 
 	n++;
 	argv = dss_realloc(argv, (n + 1) * sizeof(char *));
@@ -1611,12 +1616,23 @@ static int com_run(void)
 		DSS_ERROR_LOG(("pid %d\n", (int)pid));
 		return -E_ALREADY_RUNNING;
 	}
+	/*
+	 * Order is important here: Since daemon_init() forks, it would drop
+	 * the lock if it had been acquired already. Changing the cwd before
+	 * grabbing the lock causes stat(2) to fail in case a relative config
+	 * file path was given, which results in a different key ID for
+	 * locking. Therefore we must first daemonize, then lock, then change
+	 * the cwd.
+	 */
 	if (OPT_GIVEN(RUN, DAEMON)) {
 		fd = daemon_init();
 		daemonized = true;
 		logfile = open_log(OPT_STRING_VAL(RUN, LOGFILE));
 	}
 	lock_dss_or_die();
+	ret = change_to_dest_dir();
+	if (ret < 0)
+		return ret;
 	dump_dss_config("startup");
 	ret = install_sighandler(SIGHUP);
 	if (ret < 0)
@@ -1648,55 +1664,58 @@ static int com_prune(void)
 	struct snapshot_list sl;
 	struct snapshot *victim;
 	struct disk_space ds;
-	const char *why;
+	char *why;
+	bool try_hard;
 
 	lock_dss_or_die();
-	ret = get_disk_space(".", &ds);
+	ret = change_to_dest_dir();
 	if (ret < 0)
 		return ret;
-	log_disk_space(&ds);
+	switch (OPT_UINT32_VAL(PRUNE, DISK_SPACE)) {
+	case FDS_LOW: try_hard = true; break;
+	case FDS_HIGH: try_hard = false; break;
+	default:
+		ret = get_disk_space(".", &ds);
+		if (ret < 0)
+			return ret;
+		log_disk_space(&ds);
+		try_hard = disk_space_low(&ds);
+	}
 	dss_get_snapshot_list(&sl);
-	why = "outdated";
-	victim = find_outdated_snapshot(&sl);
-	if (victim)
-		goto rm;
-	why = "redundant";
-	victim = find_redundant_snapshot(&sl);
-	if (victim)
-		goto rm;
-	ret = 0;
-	goto out;
-rm:
+	victim = find_removable_snapshot(&sl, try_hard, &why);
+	if (!victim) {
+		dss_msg("nothing to prune\n");
+		ret = 0;
+		goto free_sl;
+	}
 	if (OPT_GIVEN(DSS, DRY_RUN)) {
-		dss_msg("%s snapshot %s (interval = %i)\n",
+		dss_msg("picking %s snapshot %s (interval = %i)\n",
 			why, victim->name, victim->interval);
 		ret = 0;
-		goto out;
+		goto free_why;
 	}
 	pre_remove_hook(victim, why);
 	if (snapshot_removal_status == HS_PRE_RUNNING) {
 		ret = wait_for_remove_process();
 		if (ret < 0)
-			goto out;
+			goto free_why;
+		ret = -E_HOOK_FAILED;
 		if (snapshot_removal_status != HS_PRE_SUCCESS)
-			goto out;
+			goto free_why;
 	}
 	ret = exec_rm();
 	if (ret < 0)
-		goto out;
+		goto free_why;
 	ret = wait_for_remove_process();
 	if (ret < 0)
-		goto out;
-	if (snapshot_removal_status != HS_SUCCESS)
-		goto out;
+		goto free_why;
+	assert(snapshot_removal_status == HS_SUCCESS);
 	post_remove_hook();
-	if (snapshot_removal_status != HS_POST_RUNNING)
-		goto out;
+	assert(snapshot_removal_status == HS_POST_RUNNING);
 	ret = wait_for_remove_process();
-	if (ret < 0)
-		goto out;
-	ret = 1;
-out:
+free_why:
+	free(why);
+free_sl:
 	free_snapshot_list(&sl);
 	return ret;
 }
@@ -1708,6 +1727,9 @@ static int com_create(void)
 	char **rsync_argv;
 
 	lock_dss_or_die();
+	ret = change_to_dest_dir();
+	if (ret < 0)
+		return ret;
 	if (OPT_GIVEN(DSS, DRY_RUN)) {
 		int i;
 		char *msg = NULL;
@@ -1753,11 +1775,14 @@ EXPORT_CMD_HANDLER(create);
 
 static int com_ls(void)
 {
-	int i;
+	int i, ret;
 	struct snapshot_list sl;
 	struct snapshot *s;
 	int64_t now = get_current_time();
 
+	ret = change_to_dest_dir();
+	if (ret < 0)
+		return ret;
 	dss_get_snapshot_list(&sl);
 	FOR_EACH_SNAPSHOT(s, i, &sl) {
 		int64_t d;