tests: use odirect

Fill snaphot with odirect so we know data hits disk
before we test how full the snapshot is.

test/api/percent.sh

@@ -21,9 +21,9 @@ vgcreate -s 4k $vg $(cat DEVICES)
 lvcreate -aey -l 5 -n foo $vg
 lvcreate -s -n snap $vg/foo -l 3 -c 4k
 lvcreate -s -n snap2 $vg/foo -l 6 -c 4k
-dd if=/dev/urandom of="$DM_DEV_DIR/$vg/snap2" count=1 bs=1024
+dd if=/dev/zero of="$DM_DEV_DIR/$vg/snap2" count=1 bs=1024 oflag=direct
 lvcreate -aey --type mirror -m 1 -n mirr $vg -l 1 --mirrorlog core
-lvs $vg
+lvs -a $vg
 aux apitest percent $vg
 
 vgremove -ff $vg

test/shell/lvextend-snapshot-dmeventd.sh

@@ -16,8 +16,7 @@ extend() {
 }
 
 write_() {
-	dd if=/dev/zero of="$DM_DEV_DIR/$vg/snap" bs=1k count=$2 seek=$1
-	sync
+	dd if=/dev/zero of="$DM_DEV_DIR/$vg/snap" bs=1k count=$2 seek=$1 oflag=direct
 }
 
 percent_() {

test/shell/snapshot-autoumount-dmeventd.sh

@@ -32,8 +32,8 @@ mkdir "$mntdir"
 mount "$DM_DEV_DIR/mapper/$vg-snap" "$mntdir"
 mount
 cat /proc/mounts | grep "$mntdir"
-dd if=/dev/zero of="$mntdir/file$1" bs=1M count=5
-sync
+dd if=/dev/zero of="$mntdir/file$1" bs=1M count=5 oflag=direct
+
 #dmeventd only checks every 10 seconds :(
 for i in {1..10}; do
 	cat /proc/mounts | grep "$mntdir" || break

test/shell/snapshot-maxsize.sh

@@ -22,7 +22,7 @@ lvcreate -aey -L1 -n $lv1 $vg
 # Snapshot should be large enough to handle any writes
 lvcreate -L2 -s $vg/$lv1 -n $lv2
 
-dd if=/dev/zero of="$DM_DEV_DIR/$vg/$lv2" bs=1M count=1
+dd if=/dev/zero of="$DM_DEV_DIR/$vg/$lv2" bs=1M count=1 oflag=direct
 
 # Snapshot must not be 'I'nvalid here
 check lv_attr_bit state $vg/$lv2 "a"