zram/overlayfs: reliable swap init and image-owned init-script refresh

meta-opencentauri/images/files/overlayfs-etc-preinit.sh.in

@@ -58,6 +58,34 @@ then
     mkdir -p $UPPER_DIR
     mkdir -p $WORK_DIR
 
+    # Remove local overlay edits to Cosmos-provided init scripts so upgrades
+    # use the new image versions. User-provided init scripts are preserved,
+    # matching previous Cosmos behavior; if an update breaks one, it is the
+    # user's responsibility to fix or remove it.
+    if [ -d "$UPPER_DIR/init.d" ]; then
+        for upper_script in "$UPPER_DIR"/init.d/*; do
+            [ -f "$upper_script" ] || continue
+            script_name=${{upper_script##*/}}
+            [ -f "/etc/init.d/$script_name" ] || continue
+            rm -f "$upper_script"
+        done
+
+        # Remove whiteouts only when they hide an image-owned init script.
+        for whiteout in "$UPPER_DIR"/init.d/.wh.*; do
+            [ -e "$whiteout" ] || continue
+            whiteout_name=${{whiteout##*/}}
+            case "$whiteout_name" in
+                .wh..wh..opq)
+                    rm -f "$whiteout"
+                    ;;
+                .wh.*)
+                    script_name=${{whiteout_name#.wh.}}
+                    [ -f "/etc/init.d/$script_name" ] && rm -f "$whiteout"
+                    ;;
+            esac
+        done
+    fi
+
     if {OVERLAYFS_ETC_EXPOSE_LOWER}; then
         mkdir -p $LOWER_DIR
 

meta-opencentauri/recipes-core/zram/files/init

@@ -1,72 +1,84 @@
 #!/bin/sh
 ### BEGIN INIT INFO
-# Provides: zram
+# Provides:          zram
 # Required-Start:
 # Required-Stop:
 # Default-Start: 2 3 4 5
 # Default-Stop: 0 1 6
-# Short-Description: Increased Performance In Linux With zRam (Virtual Swap Compressed in RAM)
-# Description: Adapted from zram init script in meta-openembedded
+# Short-Description: zram swap with retries and logging
 ### END INIT INFO
-set -e
+
+NAME=zram
+ZRAM_DEV=${ZRAM_DEV:-/dev/zram0}
+SYSFS=${ZRAM_SYSFS:-/sys/block/zram0}
+PROC_SWAPS=${PROC_SWAPS:-/proc/swaps}
+MEMINFO=${MEMINFO:-/proc/meminfo}
+SYSCTL_DIR=${SYSCTL_DIR:-/proc/sys}
+ATTEMPTS=5
+
+log() {
+    logger -t "$NAME" "$*" 2>/dev/null || true
+    echo "$NAME: $*"
+}
+
+is_active() {
+    grep -q "^${ZRAM_DEV}[[:space:]]" $PROC_SWAPS 2>/dev/null
+}
 
 start() {
     #default Factor % = 200 change this value here or create /etc/default/zram
     FACTOR=200
-    #& put the above single line in /etc/default/zram with the value you want
     [ -f /etc/default/zram ] && . /etc/default/zram || true
-    factor=$FACTOR # percentage
 
-    # get the amount of memory in the machine
-    memtotal=$(grep MemTotal /proc/meminfo | awk ' { print $2 } ')
-    disksize=$(($memtotal*$factor/100*1024))
+    if is_active; then
+        log "already active"
+        return 0
+    fi
+
+    memtotal=$(awk '/^MemTotal:/ { print $2; exit }' $MEMINFO)
+    disksize=$((memtotal * FACTOR / 100 * 1024))
+    log "memtotal=${memtotal}kB disksize=${disksize}B factor=${FACTOR}%"
 
-    # load dependency modules
-    modprobe zram num_devices=1
-    echo "zram devices probed successfully"
+    attempt=1
+    while [ "$attempt" -le "$ATTEMPTS" ]; do
+        log "attempt $attempt/$ATTEMPTS"
 
-    echo 1 > /sys/block/zram0/reset
-    echo lz4 > /sys/block/zram0/comp_algorithm
-    echo $disksize > /sys/block/zram0/disksize
+        modprobe zram num_devices=1 && \
+        echo 1 > "$SYSFS/reset" && \
+        echo lz4 > "$SYSFS/comp_algorithm" && \
+        echo "$disksize" > "$SYSFS/disksize" && \
+        mkswap "$ZRAM_DEV" && \
+        swapon -p 100 "$ZRAM_DEV"
 
-    # Creating swap filesystems
-    mkswap /dev/zram0
+        if is_active; then
+            echo 150 > $SYSCTL_DIR/vm/swappiness
+            echo 0   > $SYSCTL_DIR/vm/watermark_boost_factor
+            echo 125 > $SYSCTL_DIR/vm/watermark_scale_factor
+            echo 0   > $SYSCTL_DIR/vm/page-cluster
+            echo 500 > $SYSCTL_DIR/vm/vfs_cache_pressure
+            log "active: $(grep "^${ZRAM_DEV}[[:space:]]" $PROC_SWAPS)"
+            return 0
+        fi
 
-    # zram tuning
-    echo 150 > /proc/sys/vm/swappiness
-    echo 0   > /proc/sys/vm/watermark_boost_factor
-    echo 125 > /proc/sys/vm/watermark_scale_factor
-    echo 0   > /proc/sys/vm/page-cluster
-    echo 500 > /proc/sys/vm/vfs_cache_pressure
+        log "attempt $attempt failed"
+        swapoff "$ZRAM_DEV" 2>/dev/null || true
+        attempt=$((attempt + 1))
+        sleep 1
+    done
 
-    # Switch the swaps on
-    swapon -p 100 /dev/zram0
+    log "ERROR: no swap after $ATTEMPTS attempts"
+    return 1
 }
 
 stop() {
-    # Switching off swap
-    if [ "$(grep /dev/zram0 /proc/swaps)" != "" ]; then
-        swapoff /dev/zram0
-        sleep 1
-    fi
-    sleep 1
-    rmmod zram
+    is_active && swapoff "$ZRAM_DEV"
+    echo 1 > "$SYSFS/reset" 2>/dev/null || true
+    rmmod zram 2>/dev/null || true
 }
 
 case "$1" in
-    start)
-        start
-        ;;
-    stop)
-        stop
-        ;;
-    restart)
-        stop
-        sleep 3
-        start
-        ;;
-    *)
-        echo "Usage: $0 {start|stop|restart}"
-        RETVAL=1
+    start)   start ;;
+    stop)    stop ;;
+    restart) stop; sleep 1; start ;;
+    *)       echo "Usage: $0 {start|stop|restart}"; exit 1 ;;
 esac
-exit $RETVAL

meta-opencentauri/recipes-core/zram/tests/init-test.sh

@@ -0,0 +1,102 @@
+#!/bin/sh
+# Host smoke test for the zram init script. Fakes modprobe/mkswap/swapon etc.
+set -u
+SCRIPT=$(cd "$(dirname "$0")/../files" && pwd)/init
+ROOT=$(mktemp -d "${TMPDIR:-/tmp}/zram-test.XXXXXX")
+FAILED=0
+trap 'rm -rf "$ROOT"' EXIT
+
+setup() {
+    CASE="$ROOT/case"
+    rm -rf "$CASE"
+    mkdir -p "$CASE/bin" "$CASE/sys/block/zram0" "$CASE/proc/sys/vm"
+    printf 'Filename\t\t\tType\t\tSize\tUsed\tPriority\n' > "$CASE/proc/swaps"
+    printf 'MemTotal:       114656 kB\n' > "$CASE/proc/meminfo"
+    : > "$CASE/sys/block/zram0/reset"
+    : > "$CASE/sys/block/zram0/comp_algorithm"
+    : > "$CASE/sys/block/zram0/disksize"
+    : > "$CASE/log"
+    rm -f "$CASE"/fail-* "$CASE"/always-fail-*
+
+    for key in swappiness watermark_boost_factor watermark_scale_factor page-cluster vfs_cache_pressure; do
+        : > "$CASE/proc/sys/vm/$key"
+    done
+
+    cat > "$CASE/bin/logger" <<'EOF'
+#!/bin/sh
+printf '%s\n' "$*" >> "$CASE/log"
+EOF
+    cat > "$CASE/bin/modprobe" <<'EOF'
+#!/bin/sh
+[ -f "$CASE/fail-modprobe-once" ] && { rm -f "$CASE/fail-modprobe-once"; exit 1; }
+[ -f "$CASE/always-fail-modprobe" ] && exit 1
+exit 0
+EOF
+    cat > "$CASE/bin/mkswap" <<'EOF'
+#!/bin/sh
+exit 0
+EOF
+    cat > "$CASE/bin/swapon" <<'EOF'
+#!/bin/sh
+[ -f "$CASE/fail-swapon-once" ] && { rm -f "$CASE/fail-swapon-once"; exit 1; }
+grep -q "^${ZRAM_DEV}[[:space:]]" "$PROC_SWAPS" 2>/dev/null || \
+    printf '%s\tpartition\t235520\t0\t100\n' "$ZRAM_DEV" >> "$PROC_SWAPS"
+exit 0
+EOF
+    cat > "$CASE/bin/swapoff" <<'EOF'
+#!/bin/sh
+tmp="$PROC_SWAPS.tmp"
+awk -v dev="$ZRAM_DEV" 'NR == 1 || $1 != dev { print }' "$PROC_SWAPS" > "$tmp"
+mv "$tmp" "$PROC_SWAPS"
+exit 0
+EOF
+    cat > "$CASE/bin/rmmod" <<'EOF'
+#!/bin/sh
+exit 0
+EOF
+    cat > "$CASE/bin/sleep" <<'EOF'
+#!/bin/sh
+exit 0
+EOF
+    chmod 0755 "$CASE"/bin/*
+}
+
+run_init() {
+    env PATH="$CASE/bin:/bin:/usr/bin" \
+        CASE="$CASE" \
+        ZRAM_DEV="$CASE/zram0" \
+        ZRAM_SYSFS="$CASE/sys/block/zram0" \
+        PROC_SWAPS="$CASE/proc/swaps" \
+        MEMINFO="$CASE/proc/meminfo" \
+        SYSCTL_DIR="$CASE/proc/sys" \
+        "$SCRIPT" "$@"
+}
+
+check() {
+    desc="$1"; shift
+    if "$@"; then echo "ok: $desc"; else echo "FAIL: $desc"; FAILED=1; fi
+}
+
+# success + idempotence
+setup
+run_init start >/dev/null
+check "start succeeds" grep -q "$CASE/zram0" "$CASE/proc/swaps"
+check "logs success" grep -q "active:" "$CASE/log"
+run_init start >/dev/null
+check "second start is no-op" grep -q "already active" "$CASE/log"
+
+# retry after one modprobe failure
+setup
+: > "$CASE/fail-modprobe-once"
+run_init start >/dev/null
+check "recovers from one modprobe failure" grep -q "$CASE/zram0" "$CASE/proc/swaps"
+check "logged attempt 2" grep -q "attempt 2/5" "$CASE/log"
+
+# bounded failure
+setup
+: > "$CASE/always-fail-modprobe"
+run_init start >/dev/null && { echo "FAIL: permanent modprobe failure should not succeed"; FAILED=1; }
+check "gives up after 5 attempts" grep -q "after 5 attempts" "$CASE/log"
+check "no swap left active" sh -c "! grep -q \"$CASE/zram0\" \"$CASE/proc/swaps\""
+
+[ "$FAILED" -eq 0 ] && echo "PASS" || exit 1