add image container probing via qemu-img

1 files changed, 31 insertions, 10 deletions

diff --git a/builder/dnbd3-rootfs/hooks/pre-mount/prepare-root-partition.sh b/builder/dnbd3-rootfs/hooks/pre-mount/prepare-root-partition.sh
index 2b266012..fc99226d 100755
--- a/builder/dnbd3-rootfs/hooks/pre-mount/prepare-root-partition.sh
+++ b/builder/dnbd3-rootfs/hooks/pre-mount/prepare-root-partition.sh
@@ -1,9 +1,12 @@
+# region imports
 source "/usr/lib/rebash/core.sh"
 core.import utils
 core.import logging
 logging.set_commands_log_level debug
 logging.set_log_level debug
+# endregion
 
+# region connect dnbd3
 # Close previous connections to be able to run this script many times.
 dnbd3-client --device "$SLX_DNBD3_DEVICE" --close
 local IFS_backup="$IFS"
@@ -19,32 +22,39 @@ for host in ${SLX_DNBD3_SERVERS}; do
     continue
 done
 IFS="$IFS_backup"
+
 if [[ $return_code != 0 ]]; then
     warn "Failed to connect '${SLX_SERVER_BASE#/}${SLX_DNBD3_IMAGE}' from" \
         "one of '$SLX_DNBD3_SERVERS' to '$SLX_DNBD3_DEVICE'."
     emergency_shell -n "Error in $0"
     return 1
 fi
-local nbd_device='/dev/nbd0'
-systemd-preserve-process-marker qemu-nbd --connect="$nbd_device" \
-    "$SLX_DNBD3_DEVICE" --read-only
+# endregion
+
+# region detect read-only partition
+local read_only_device="$SLX_DNBD3_DEVICE"
+if ! qemu-img info --output json "$read_only_device" | grep '"format": "raw"'
+then
+    read_only_device='/dev/nbd0'
+    systemd-preserve-process-marker qemu-nbd --connect="$read_only_device" \
+        "$SLX_DNBD3_DEVICE" --read-only
 
-# TODO make nicer :)
-touch $nbd_device
-udevadm settle
+    # wait for partitions TODO make nicer :)
+    touch $read_only_device
+    udevadm settle
+fi
 
 local read_only_partition
 if ! read_only_partition=$(utils.find_block_device \
-        "$SLX_SYSTEM_PARTITION_IDENTIFIER" "$nbd_device"); then
+        "$SLX_SYSTEM_PARTITION_IDENTIFIER" "$read_only_device"); then
     logging.warn "Failed to find unique device with identifier" \
         "'${SLX_SYSTEM_PARTITION_IDENTIFIER}'; matched devices:" \
         "'${read_only_partition}'"
     emergency_shell
 fi
+# endregion
 
-# Make read-only partition writable.
-
-## detect partition for persistent storage
+# region detect writable partition
 local persistent_device
 if ! persistent_device=$(utils.find_block_device \
         "$SLX_WRITABLE_DEVICE_IDENTIFIER"); then
@@ -84,6 +94,9 @@ fi
 #losetup "$writable_device" persistent_storage.img
 #persistent='P'
 
+# endregion
+
+# region combine devices with device mapper
 local partition_size="$(blockdev --getsz "$read_only_partition")"
 local writable_partition_name='root'
 logging.info "Using read-only device: $read_only_partition"
@@ -93,3 +106,11 @@ modprobe dm_snapshot
 dmsetup create "$writable_partition_name" --noudevsync --table \
     "0 $partition_size snapshot $read_only_partition $writable_device $persistent $chunksize"
 dmsetup mknodes --noudevsync "$writable_partition_name"
+# enregion
+
+# region vim modline
+
+# vim: set tabstop=4 shiftwidth=4 expandtab:
+# vim: foldmethod=marker foldmarker=region,endregion:
+
+# endregion