diff --git a/Makefile.am b/Makefile.am
index 9a932768..a7647d0e 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -139,7 +139,6 @@ clean-local:
 	rm -f cmdline/*.gcda cmdline/*.gcno cmdline/*.gcov
 	rm -f raid/*.gcda raid/*.gcno raid/*.gcov
 	rm -f tommyds/*.gcda tommyds/*.gcno tommyds/*.gcov
-	rm -rf cov
 	rm -f lcov.info
 	rm -f gmon.out
 
@@ -338,6 +337,9 @@ endif
 	rm bench/disk1/INVA1
 	touch bench/disk1/INVA2
 	$(TESTENV) ./snapraid$(EXEEXT) $(CHECKFLAGS) -c $(CONF) --test-kill-after-sync sync
+# Diff should report the need of a sync for invalid parity
+	$(FAILENV) ./snapraid$(EXEEXT) $(CHECKFLAGS_VERBOSE) -c $(PAR1) --test-expect-need-sync diff
+	$(TESTENV) ./snapraid$(EXEEXT) $(CHECKFLAGS) -c $(CONF) status
 	mv bench/disk2/MOVE2 bench/disk4/MOVE4
 	mv bench/disk3/MOVE3 bench/disk5/MOVE5
 	mv bench/disk4/MOVE4 bench/disk6/MOVE6
@@ -435,8 +437,8 @@ endif
 	$(FAILENV) ./snapraid$(EXEEXT) $(CHECKFLAGS_VERBOSE) -c $(PAR1) --test-expect-need-sync diff > output.log
 	$(TESTENV) ./snapraid$(EXEEXT) $(CHECKFLAGS) --test-skip-fallocate -c $(PAR1) sync
 	$(TESTENV) ./snapraid$(EXEEXT) $(CHECKFLAGS) -c $(CONF) status
-	$(TESTENV) ./snapraid$(EXEEXT) $(CHECKFLAGS) --test-io-advise-none -c $(PAR1) sync -F
-	$(TESTENV) ./snapraid$(EXEEXT) $(CHECKFLAGS) --test-io-advise-sequential -c $(PAR1) sync -F
+	$(TESTENV) ./snapraid$(EXEEXT) $(CHECKFLAGS) --test-io-advise-none -c $(PAR1) sync -F --test-io-cache 1
+	$(TESTENV) ./snapraid$(EXEEXT) $(CHECKFLAGS) --test-io-advise-sequential -c $(PAR1) sync -F --test-io-stats
 	$(TESTENV) ./snapraid$(EXEEXT) $(CHECKFLAGS) --test-io-advise-flush-window -c $(PAR1) sync -F
 	$(TESTENV) ./snapraid$(EXEEXT) $(CHECKFLAGS) --test-io-advise-discard-window -c $(PAR1) sync -F
 #### CHANGE LINKS ####
diff --git a/cmdline/check.c b/cmdline/check.c
index b2d120e1..835f94fc 100644
--- a/cmdline/check.c
+++ b/cmdline/check.c
@@ -909,9 +909,11 @@ static int state_check_process(struct snapraid_state* state, int fix, struct sna
 			/* post process the files */
 			ret = file_post(state, fix, i, handle, diskmax);
 			if (ret == -1) {
+				/* LCOV_EXCL_START */
 				log_fatal("Stopping at block %u\n", i);
 				++unrecoverable_error;
 				goto bail;
+				/* LCOV_EXCL_STOP */
 			}
 
 			/* and now continue with the next block */
@@ -1384,9 +1386,11 @@ static int state_check_process(struct snapraid_state* state, int fix, struct sna
 		/* post process the files */
 		ret = file_post(state, fix, i, handle, diskmax);
 		if (ret == -1) {
+			/* LCOV_EXCL_START */
 			log_fatal("Stopping at block %u\n", i);
 			++unrecoverable_error;
 			goto bail;
+			/* LCOV_EXCL_STOP */
 		}
 
 		/* count the number of processed block */
diff --git a/cmdline/dry.c b/cmdline/dry.c
index 57e642b8..54720e8a 100644
--- a/cmdline/dry.c
+++ b/cmdline/dry.c
@@ -254,12 +254,16 @@ static int state_dry_process(struct snapraid_state* state, struct snapraid_parit
 
 			/* handle error conditions */
 			if (task->state == TASK_STATE_IOERROR) {
+				/* LCOV_EXCL_START */
 				++io_error;
 				goto bail;
+				/* LCOV_EXCL_STOP */
 			}
 			if (task->state == TASK_STATE_ERROR) {
+				/* LCOV_EXCL_START */
 				++error;
 				goto bail;
+				/* LCOV_EXCL_STOP */
 			}
 			if (task->state == TASK_STATE_ERROR_CONTINUE) {
 				++error;
@@ -304,12 +308,16 @@ static int state_dry_process(struct snapraid_state* state, struct snapraid_parit
 
 			/* handle error conditions */
 			if (task->state == TASK_STATE_IOERROR) {
+				/* LCOV_EXCL_START */
 				++io_error;
 				goto bail;
+				/* LCOV_EXCL_STOP */
 			}
 			if (task->state == TASK_STATE_ERROR) {
+				/* LCOV_EXCL_START */
 				++error;
 				goto bail;
+				/* LCOV_EXCL_STOP */
 			}
 			if (task->state == TASK_STATE_ERROR_CONTINUE) {
 				++error;
diff --git a/cmdline/parity.c b/cmdline/parity.c
index 29329eb1..aa431355 100644
--- a/cmdline/parity.c
+++ b/cmdline/parity.c
@@ -530,8 +530,11 @@ int parity_chsize(struct snapraid_parity_handle* handle, struct snapraid_parity*
 	/* mask of bits used by the block size */
 	block_mask = ((data_off_t)block_size) - 1;
 
-	if (size < 0)
+	if (size < 0) {
+		/* LCOV_EXCL_START */
 		return -1;
+		/* LCOV_EXCL_STOP */
+	}
 
 	for (s = 0;s < handle->split_mac;++s) {
 		struct snapraid_split_handle* split = &handle->split_map[s];
@@ -563,8 +566,11 @@ int parity_chsize(struct snapraid_parity_handle* handle, struct snapraid_parity*
 		}
 		
 		ret = parity_handle_chsize(split, run, block_size, skip_fallocate, skip_space_holder);
-		if (ret != 0)
+		if (ret != 0) {
+			/* LCOV_EXCL_START */
 			return -1;
+			/* LCOV_EXCL_STOP */
+		}
 
 		if (split->st.st_size > run) {
 			/* LCOV_EXCL_START */
@@ -597,8 +603,10 @@ int parity_chsize(struct snapraid_parity_handle* handle, struct snapraid_parity*
 
 	/* if we cannot allocate all the space */
 	if (size != 0) {
+		/* LCOV_EXCL_START */
 		log_fatal("Failed to allocate all the required parity space. You miss %" PRIu64 " bytes.\n", size);
 		return -1;
+		/* LCOV_EXCL_STOP */
 	}
 
 	/* now copy the new size in the parity data */
diff --git a/cmdline/scrub.c b/cmdline/scrub.c
index 1936a845..742c6dad 100644
--- a/cmdline/scrub.c
+++ b/cmdline/scrub.c
@@ -414,12 +414,16 @@ static int state_scrub_process(struct snapraid_state* state, struct snapraid_par
 
 			/* handle error conditions */
 			if (task->state == TASK_STATE_IOERROR) {
+				/* LCOV_EXCL_START */
 				++io_error;
 				goto bail;
+				/* LCOV_EXCL_STOP */
 			}
 			if (task->state == TASK_STATE_ERROR) {
+				/* LCOV_EXCL_START */
 				++error;
 				goto bail;
+				/* LCOV_EXCL_STOP */
 			}
 			if (task->state == TASK_STATE_ERROR_CONTINUE) {
 				++error;
@@ -506,12 +510,16 @@ static int state_scrub_process(struct snapraid_state* state, struct snapraid_par
 
 			/* handle error conditions */
 			if (task->state == TASK_STATE_IOERROR) {
+				/* LCOV_EXCL_START */
 				++io_error;
 				goto bail;
+				/* LCOV_EXCL_STOP */
 			}
 			if (task->state == TASK_STATE_ERROR) {
+				/* LCOV_EXCL_START */
 				++error;
 				goto bail;
+				/* LCOV_EXCL_STOP */
 			}
 			if (task->state == TASK_STATE_ERROR_CONTINUE) {
 				++error;
diff --git a/cmdline/selftest.c b/cmdline/selftest.c
index 99b6a94f..26a95999 100644
--- a/cmdline/selftest.c
+++ b/cmdline/selftest.c
@@ -406,6 +406,14 @@ static void test_tommy(void)
 		/* LCOV_EXCL_STOP */
 	}
 
+	tommy_list_insert_tail(&list, &node[0], &node[0]);
+
+	if (tommy_list_tail(&list) != tommy_list_head(&list)) {
+		/* LCOV_EXCL_START */
+		goto bail;
+		/* LCOV_EXCL_STOP */
+	}
+
 	tommy_hashdyn_init(&hashdyn);
 
 	for (i = 0; i < TOMMY_SIZE; ++i)
diff --git a/cmdline/sync.c b/cmdline/sync.c
index bababec1..1d59c10a 100644
--- a/cmdline/sync.c
+++ b/cmdline/sync.c
@@ -884,12 +884,16 @@ static int state_sync_process(struct snapraid_state* state, struct snapraid_pari
 
 			/* handle error conditions */
 			if (task->state == TASK_STATE_IOERROR) {
+				/* LCOV_EXCL_START */
 				++io_error;
 				goto bail;
+				/* LCOV_EXCL_STOP */
 			}
 			if (task->state == TASK_STATE_ERROR) {
+				/* LCOV_EXCL_START */
 				++error;
 				goto bail;
+				/* LCOV_EXCL_STOP */
 			}
 			if (task->state == TASK_STATE_ERROR_CONTINUE) {
 				++error;
@@ -899,10 +903,12 @@ static int state_sync_process(struct snapraid_state* state, struct snapraid_pari
 			if (task->state == TASK_STATE_IOERROR_CONTINUE) {
 				++io_error;
 				if (io_error >= state->opt.io_error_limit) {
+					/* LCOV_EXCL_START */
 					log_fatal("DANGER! Unexpected input/output read error in a data disk, it isn't possible to sync.\n");
 					log_fatal("Ensure that disk '%s' is sane and that file '%s' can be read.\n", disk->dir, task->path);
 					log_fatal("Stopping at block %u\n", blockcur);
 					goto bail;
+					/* LCOV_EXCL_STOP */
 				}
 
 				/* otherwise continue */
@@ -1245,20 +1251,26 @@ static int state_sync_process(struct snapraid_state* state, struct snapraid_pari
 				case TASK_STATE_IOERROR_CONTINUE :
 					++io_error;
 					if (io_error >= state->opt.io_error_limit) {
+						/* LCOV_EXCL_START */
 						log_fatal("DANGER! Unexpected input/output write error in a parity disk, it isn't possible to sync.\n");
 						log_fatal("Stopping at block %u\n", blockcur);
 						goto bail;
+						/* LCOV_EXCL_STOP */
 					}
 					break;
 				case TASK_STATE_ERROR_CONTINUE :
 					++error;
 					break;
 				case TASK_STATE_IOERROR :
+					/* LCOV_EXCL_START */
 					++io_error;
 					goto bail;
+					/* LCOV_EXCL_STOP */
 				case TASK_STATE_ERROR :
+					/* LCOV_EXCL_START */
 					++error;
 					goto bail;
+					/* LCOV_EXCL_STOP */
 				}
 			}
 		}
diff --git a/makecov.sh b/makecov.sh
index f030361e..4a0bbd99 100755
--- a/makecov.sh
+++ b/makecov.sh
@@ -5,7 +5,7 @@
 
 make distclean
 
-if ! ./configure --enable-coverage; then
+if ! ./configure --enable-coverage --enable-sde; then
 	exit 1
 fi
 
diff --git a/maketest.sh b/maketest.sh
index 63f7d239..75c746cf 100755
--- a/maketest.sh
+++ b/maketest.sh
@@ -14,10 +14,6 @@ if ! make lcov_reset check lcov_capture lcov_html; then
 	exit 1
 fi
 
-# Keep a copy of the coverage results
-rm -rf cov_release
-mv cov cov_release
-
 if ! make distclean; then
 	exit 1
 fi