Merge pull request vianney#3 from guns/remount-ext4-with-nobarrier

Remount / with barrier=0 when fstype is ext4

arch-luks-suspend

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 
 set -e -u
 trap 'echo "Press ENTER to continue."; read dummy' ERR
@@ -9,22 +9,33 @@ trap 'echo "Press ENTER to continue."; read dummy' ERR
 INITRAMFS_DIR=/run/initramfs
 SYSTEM_SLEEP_PATH=/usr/lib/systemd/system-sleep
 BIND_PATHS="/sys /proc /dev /run"
+REMOUNT=0
+# Retrieve cryptdevice name from boot cmdline
+CRYPTNAME="$(sed -n 's/.*cryptdevice=[^: ]*:\([^: ]*\).*$/\1/p' /proc/cmdline)"
 
 # run_dir DIR ARGS...
 # Run all executable scripts in directory DIR with arguments ARGS
 run_dir() {
-    dir=$1
+    local dir=$1
     shift
     find "${dir}" -type f -executable -exec "{}" "$@" ";"
 }
 
 # Restore chroot
 umount_initramfs() {
+    local p
     for p in ${BIND_PATHS}; do
         ! mountpoint -q "${INITRAMFS_DIR}${p}" || umount "${INITRAMFS_DIR}${p}"
     done
 }
 
+ext4_cryptdevice_mount_options() {
+    local mt="$(grep "^/dev/mapper/${1} " /proc/mounts | cut -d ' ' -f 3,4)"
+    if [[ "${mt:0:5}" == "ext4 " ]]; then
+        echo "${mt:5}"
+    fi
+}
+
 ################################################################################
 ## Main script
 
@@ -46,12 +57,26 @@ systemctl stop systemd-udevd-control.socket
 systemctl stop systemd-udevd-kernel.socket
 systemctl stop systemd-udevd.service
 
+# Journalled ext4 filesystems in kernel versions 3.11+ will block suspend
+# if mounted with `barrier=1`, which is the default. Temporarily remount with
+# `barrier=0` if this is true of the crypt fs.
+MOUNT_OPTS="$(ext4_cryptdevice_mount_options "$CRYPTNAME")"
+if [[ "$MOUNT_OPTS" ]] && ! [[ "$MOUNT_OPTS" == *nobarrier* || "$MOUNT_OPTS" == *barrier=0* ]]; then
+    REMOUNT=1
+    mount -o remount,"$MOUNT_OPTS",barrier=0 /
+fi
+
 # Synchronize filesystems before luksSuspend
 sync
 
 # Hand over execution to script inside initramfs
 cd "${INITRAMFS_DIR}"
-chroot . /suspend
+chroot . /suspend "$CRYPTNAME"
+
+# Restore original mount options if necessary
+if ((REMOUNT)); then
+    mount -o remount,"$MOUNT_OPTS",barrier=1 /
+fi
 
 # Restart udev
 systemctl start systemd-udevd-control.socket

initramfs-suspend

@@ -1,11 +1,10 @@
 #!/usr/bin/ash
 
+cryptname="${1}"
+
 # Start udev from initramfs
 /usr/lib/systemd/systemd-udevd --daemon --resolve-names=never
 
-# Retrieve cryptdevice name from boot cmdline
-cryptname=$(sed -n 's/.*cryptdevice=[^: ]*:\([^: ]*\).*$/\1/p' /proc/cmdline)
-
 # Suspend root device
 [ -z "${cryptname}" ] || cryptsetup luksSuspend "${cryptname}"