3 files changed, 43 insertions, 20 deletions

diff --git a/initramfs-tools/hooks/samizdat b/initramfs-tools/hooks/samizdat
index d09c660..c854186 100755
--- a/initramfs-tools/hooks/samizdat
+++ b/initramfs-tools/hooks/samizdat
@@ -5,7 +5,7 @@ CopyExec() { copy_exec "$@" || exit 1; }
 
 . /usr/share/initramfs-tools/hook-functions
 
-for f in ./old-school/*; do CopyExec "$f" /bin; done
+for f in ./old-school/* loop-layer.sh; do CopyExec "$f" /bin; done
 
 # TODO: check samizdat source to see what it copies
 path_execs='mountpoint openvt rsync gpg2 gpg-agent pinentry-curses truncate cryptsetup mkfs.btrfs btrfs'
diff --git a/loop-layer.sh b/loop-layer.sh
new file mode 100644
index 0000000..7e08e12
--- /dev/null
+++ b/loop-layer.sh
@@ -0,0 +1,15 @@
+losetup_snapshot()
+{
+    local ro_dev rw_dev new_dev_name size persist chunksize
+    ro_file=$1
+    rw_file=$2
+
+    ro_dev=$(LoSetup -r -f --show "$ro_file") || return
+    rw_dev=$(LoSetup -f --show "$rw_file") || return
+    new_dev_name=${ro_dev##*/}
+    size=$(blockdev --getsz "$ro_dev") || return
+    persist=p
+    chunksize=16
+    dmsetup create "$new_dev_name" --table "0 $size snapshot $ro_dev $rw_dev $persist $chunksize" || return
+    echo /dev/mapper/"$new_dev_name"
+}
diff --git a/old-school/lvm-create.sh b/old-school/lvm-create.sh
index 743b83a..ecbae49 100644
--- a/old-school/lvm-create.sh
+++ b/old-school/lvm-create.sh
@@ -26,16 +26,25 @@ ceil4()
   printf '%d\n' "$x"
 }
 
+. loop-layer.sh
+
+losetup_layers()
+{
+    for fs in /cdrom/live/*.btrfs; do
+        fs_rw=/"${fs##*/}".rw
+        dd if=/dev/zero of="$fs_rw" bs=1M count=10
+        losetup_snapshot "$fs" "$fs_rw" || return
+    done
+}
+
 init_samizdat()
 {
-  local imgfile="$1" megs="$2" keyfile="$3" dev
+  local imgfile="$1" megs="$2" keyfile="$3" dev fs fs_rw
 
   init_samizdat_blockdev "$imgfile" "$megs" "$keyfile" || return
   local blockdev=/dev/mapper/samizdatcrypt uuid
 
-  for fs in /cdrom/live/*.btrfs; do
-      losetup -f "$fs" || return
-  done
+  losetup_layers || return
   modprobe btrfs || return
   btrfs device scan || return
 
@@ -47,17 +56,6 @@ init_samizdat()
   btrfs device add "$blockdev" /root || return
   mount -o rw,remount /root || return
   btrfs subvolume create /root/gpg || return
-  # TODO: Restart gpg agent with stored credentials.
-
-  # TODO: Actually, if we unconditionally added a ramdisk, we could go
-  # ahead with the boot, and then do this whole thing from the installed
-  # system (after pivot_root).  That way, there would be no need to
-  # restart.
-
-  # Really, the option to install could be identical to the option to
-  # boot from RAM except that it would record the intent to install; or
-  # else it could be removed entirely, with an option to persist added
-  # as some kind of UI element.
   mv /gpg/gnupghome /root/gpg/ || return
 
   bootdone root-mounted
@@ -82,7 +80,7 @@ choose_uuid()
                     seen_devs=${line#*Total devices }
                     seen_devs=${seen_devs%% *}
                     ;;
-                *path\ /dev/loop*)
+                *path\ /dev/mapper/*)
                     seen_loop=t;;
             esac
             [ "$seen_loop" ] && echo "$seen_devs $seen_uuid"
@@ -90,13 +88,23 @@ choose_uuid()
         uniq | sort -nr | head -n1 | (read _ x; echo $x)
 }
 
+filesystem_incomplete()
+{
+    local n
+    n=$(btrfs filesystem show "$1" | sed -ne 's/.*Total devices \([^ ]*\) .*/\1/p')
+    [ "$n" != 1 ]
+}
+
 open_samizdat()
 {
   open_samizdat_blockdev "$@" || return
   local blockdev=/dev/mapper/samizdatcrypt fs
-  for fs in /cdrom/live/*.btrfs; do
-    losetup -f "$fs" || return
-  done
+
+  # For this part, we don't necessarily need the cdrom.
+  # Unfortunately the init_gpg code is still getting the GPG key there.
+  if filesystem_incomplete "$blockdev"; then
+     losetup_layers
+  fi
   modprobe btrfs || return
   btrfs device scan || return
   mount -t btrfs -o subvol=ROOT "$blockdev" /root || return