diff -ur nilfs2-utils.orig/man/nilfs_cleanerd.conf.5 nilfs2-utils/man/nilfs_cleanerd.conf.5
--- nilfs2-utils.orig/man/nilfs_cleanerd.conf.5	2010-03-14 15:11:30.916690347 +0100
+++ nilfs2-utils/man/nilfs_cleanerd.conf.5	2010-03-15 22:15:58.320507660 +0100
@@ -25,6 +25,23 @@
 and their blocks whose duration time is less than the value.  The
 default value is 3600, meaning one hour.
 .TP
+.B min_clean_segments
+Specify the minimum number of clean segments. A value of 0 means
+normal cleaner operation. A value greater than 0 means pause cleaning
+until less than min_clean_segments are available. The default value
+is 100.
+.TP
+.B max_clean_segments
+Specify the maximum number of clean segments. If min_clean_segments is
+0, this value is ignored. If more than max_clean_segments are available
+cleaning is paused until less than min_clean_segments are available.
+The default value is 200.
+.TP
+.B clean_check_interval
+Specify the interval to wait between checks of min_clean_segments.
+If min_clean_segments is 0, this value is ignored.
+The default value is 60.
+.TP
 .B selection_policy
 Specify the GC policy. At present, only the `\fBtimestamp\fP' policy,
 which reclaims segments in order from oldest to newest, is support.
diff -ur nilfs2-utils.orig/sbin/cleanerd/cldconfig.c nilfs2-utils/sbin/cleanerd/cldconfig.c
--- nilfs2-utils.orig/sbin/cleanerd/cldconfig.c	2010-03-14 15:11:30.916690347 +0100
+++ nilfs2-utils/sbin/cleanerd/cldconfig.c	2010-03-15 20:20:22.364435601 +0100
@@ -90,6 +90,87 @@
 	return 0;
 }
 
+static int
+nilfs_cldconfig_handle_min_clean_segments(struct nilfs_cldconfig *config,
+					  char **tokens, size_t ntoks)
+{
+	__u64 n;
+	char *endptr;
+
+	if (check_tokens(tokens, ntoks, 2, 2) < 0)
+		return 0;
+
+	errno = 0;
+	n = strtoull(tokens[1], &endptr, 10);
+	if (*endptr != '\0') {
+		syslog(LOG_WARNING, "%s: %s: not a number",
+		       tokens[0], tokens[1]);
+		return 0;
+	}
+	if ((n == ULLONG_MAX) && (errno == ERANGE)) {
+		syslog(LOG_WARNING, "%s: %s: number too large",
+		       tokens[0], tokens[1]);
+		return 0;
+	}
+
+	config->cf_min_clean_segments = n;
+	return 0;
+}
+
+static int
+nilfs_cldconfig_handle_max_clean_segments(struct nilfs_cldconfig *config,
+					  char **tokens, size_t ntoks)
+{
+	__u64 n;
+	char *endptr;
+
+	if (check_tokens(tokens, ntoks, 2, 2) < 0)
+		return 0;
+
+	errno = 0;
+	n = strtoull(tokens[1], &endptr, 10);
+	if (*endptr != '\0') {
+		syslog(LOG_WARNING, "%s: %s: not a number",
+		       tokens[0], tokens[1]);
+		return 0;
+	}
+	if ((n == ULLONG_MAX) && (errno == ERANGE)) {
+		syslog(LOG_WARNING, "%s: %s: number too large",
+		       tokens[0], tokens[1]);
+		return 0;
+	}
+
+	config->cf_max_clean_segments = n;
+	return 0;
+}
+
+static int
+nilfs_cldconfig_handle_clean_check_interval(struct nilfs_cldconfig *config,
+					    char **tokens, size_t ntoks)
+{
+	time_t period;
+	char *endptr;
+
+	if (check_tokens(tokens, ntoks, 2, 2) < 0)
+		return 0;
+
+	errno = 0;
+	period = strtoul(tokens[1], &endptr, 10);
+	if (*endptr != '\0') {
+		syslog(LOG_WARNING, "%s: %s: not a number",
+		       tokens[0], tokens[1]);
+		return 0;
+	}
+	if ((period == ULONG_MAX) && (errno == ERANGE)) {
+		syslog(LOG_WARNING, "%s: %s: number too large",
+		       tokens[0], tokens[1]);
+		return 0;
+	}
+
+	config->cf_clean_check_interval = period;
+	return 0;
+}
+
 static unsigned long long
 nilfs_cldconfig_selection_policy_timestamp(const struct nilfs_suinfo *si)
 {
@@ -277,6 +358,9 @@
 static const struct nilfs_cldconfig_keyword
 nilfs_cldconfig_keyword_table[] = {
 	{"protection_period",	nilfs_cldconfig_handle_protection_period},
+	{"min_clean_segments",	nilfs_cldconfig_handle_min_clean_segments},
+	{"max_clean_segments",	nilfs_cldconfig_handle_max_clean_segments},
+	{"clean_check_interval",nilfs_cldconfig_handle_clean_check_interval},
 	{"selection_policy",	nilfs_cldconfig_handle_selection_policy},
 	{"nsegments_per_clean",	nilfs_cldconfig_handle_nsegments_per_clean},
 	{"cleaning_interval",	nilfs_cldconfig_handle_cleaning_interval},
@@ -313,6 +397,9 @@
 	config->cf_selection_policy.p_threshold =
 		NILFS_CLDCONFIG_SELECTION_POLICY_THRESHOLD;
 	config->cf_protection_period = NILFS_CLDCONFIG_PROTECTION_PERIOD;
+	config->cf_min_clean_segments = NILFS_CLDCONFIG_MIN_CLEAN_SEGMENTS;
+	config->cf_max_clean_segments = NILFS_CLDCONFIG_MAX_CLEAN_SEGMENTS;
+	config->cf_clean_check_interval = NILFS_CLDCONFIG_CLEAN_CHECK_INTERVAL;
 	config->cf_nsegments_per_clean = NILFS_CLDCONFIG_NSEGMENTS_PER_CLEAN;
 	config->cf_cleaning_interval = NILFS_CLDCONFIG_CLEANING_INTERVAL;
 	config->cf_retry_interval = NILFS_CLDCONFIG_RETRY_INTERVAL;
diff -ur nilfs2-utils.orig/sbin/cleanerd/cldconfig.h nilfs2-utils/sbin/cleanerd/cldconfig.h
--- nilfs2-utils.orig/sbin/cleanerd/cldconfig.h	2010-03-14 15:11:30.916690347 +0100
+++ nilfs2-utils/sbin/cleanerd/cldconfig.h	2010-03-15 21:58:16.208614224 +0100
@@ -42,6 +42,9 @@
  * struct nilfs_cldconfig -
  * @cf_selection_policy:
  * @cf_protection_period:
+ * @cf_min_clean_segments:
+ * @cf_max_clean_segments:
+ * @cf_clean_check_interval:
  * @cf_nsegments_per_clean
  * @cf_cleaning_interval:
  * @cf_use_mmap:
@@ -50,6 +53,9 @@
 struct nilfs_cldconfig {
 	struct nilfs_selection_policy cf_selection_policy;
 	time_t cf_protection_period;
+	__u64 cf_min_clean_segments;
+	__u64 cf_max_clean_segments;
+	time_t cf_clean_check_interval;
 	int cf_nsegments_per_clean;
 	time_t cf_cleaning_interval;
 	time_t cf_retry_interval;
@@ -61,6 +67,9 @@
 			nilfs_cldconfig_selection_policy_timestamp
 #define NILFS_CLDCONFIG_SELECTION_POLICY_THRESHOLD	0
 #define NILFS_CLDCONFIG_PROTECTION_PERIOD		3600
+#define	NILFS_CLDCONFIG_MIN_CLEAN_SEGMENTS		100
+#define	NILFS_CLDCONFIG_MAX_CLEAN_SEGMENTS		200
+#define	NILFS_CLDCONFIG_CLEAN_CHECK_INTERVAL		60
 #define NILFS_CLDCONFIG_NSEGMENTS_PER_CLEAN		2
 #define NILFS_CLDCONFIG_CLEANING_INTERVAL		5
 #define NILFS_CLDCONFIG_RETRY_INTERVAL			60
diff -ur nilfs2-utils.orig/sbin/cleanerd/cleanerd.c nilfs2-utils/sbin/cleanerd/cleanerd.c
--- nilfs2-utils.orig/sbin/cleanerd/cleanerd.c	2010-03-14 15:11:30.916690347 +0100
+++ nilfs2-utils/sbin/cleanerd/cleanerd.c	2010-03-17 19:59:36.845402863 +0100
@@ -1198,9 +1198,17 @@
 	if (ret < 0)
 		return -1;
 
-	cleanerd->c_running = 1;
 	cleanerd->c_ncleansegs = cleanerd->c_config.cf_nsegments_per_clean;
 
+	if (cleanerd->c_config.cf_min_clean_segments > 0) {
+		syslog(LOG_INFO, "cleaner paused");
+		cleanerd->c_running = 0;
+		timeout.tv_sec = cleanerd->c_config.cf_clean_check_interval;
+		timeout.tv_nsec = 0;
+	}
+	else
+	  cleanerd->c_running = 1;
+
 	while (1) {
 		if (sigprocmask(SIG_BLOCK, &sigset, NULL) < 0) {
 			syslog(LOG_ERR, "cannot set signal mask: %m");
@@ -1220,10 +1228,32 @@
 			syslog(LOG_ERR, "cannot get segment usage stat: %m");
 			return -1;
 		}
+
+		if (cleanerd->c_config.cf_min_clean_segments > 0) {
+			if (cleanerd->c_running) {
+				if (sustat.ss_ncleansegs > cleanerd->c_config.cf_max_clean_segments) {
+					syslog(LOG_INFO, "cleaner paused");
+					cleanerd->c_running = 0;
+					timeout.tv_sec = cleanerd->c_config.cf_clean_check_interval;
+					timeout.tv_nsec = 0;
+					goto sleep;
+				}
+			}
+			else {
+				if (sustat.ss_ncleansegs < cleanerd->c_config.cf_min_clean_segments) {
+					syslog(LOG_INFO, "cleaner resumed");
+					cleanerd->c_running = 1;
+				}
+				else
+					goto sleep;
+			}
+		}
+
 		if (sustat.ss_nongc_ctime != prev_nongc_ctime) {
 			cleanerd->c_running = 1;
 			prev_nongc_ctime = sustat.ss_nongc_ctime;
 		}
+
 		if (!cleanerd->c_running)
 			goto sleep;
 
diff -ur nilfs2-utils.orig/sbin/cleanerd/nilfs_cleanerd.conf nilfs2-utils/sbin/cleanerd/nilfs_cleanerd.conf
--- nilfs2-utils.orig/sbin/cleanerd/nilfs_cleanerd.conf	2010-03-14 15:11:30.916690347 +0100
+++ nilfs2-utils/sbin/cleanerd/nilfs_cleanerd.conf	2010-03-15 21:44:02.995587453 +0100
@@ -7,6 +7,17 @@
 # Protection period in second.
 protection_period	3600
 
+# Minium number of clean segements 
+# 0  = normal cleaner behaviour
+# >0 = start cleaning if less segments are available
+min_clean_segments	100
+
+# Maximum number of clean segments
+max_clean_segments	200
+
+# Clean segment check interval in seconds
+clean_check_interval	60
+
 # Segment selection policy.
 # In NILFS version 2.0.0, only the timestamp policy is supported.
 selection_policy	timestamp	# timestamp in ascend order