Fix to make the btrfs install method work.

Just figured this out.

We must change the fsuid after removing the devices, because btrfs
MODIFIES the READ-ONLY SEED DEVICES to mark them unavailable after
when remove them from the read-write device.  When we reboot with the
UNMODIFIED, IMMUTABLE seed image, btrfs cannot handle the duplicate
fsuid.

We detect this situation (kind of) and call btrfstune -m to change the
fsuid of the /dev/mapper/samizdatcrypt single device fs.  Now it just
works.

It would be much better to call this on the booted system on the running
rootfs, but btrfs can't, so we instead call it on the initrd mount time.

A more proper fix might use the partition table to mark the partition as
in need of 'btrfstune -m'.

1 files changed, 7 insertions, 3 deletions

diff --git a/src/initrd/btrfs-create.sh b/src/initrd/btrfs-create.sh
index 02ce257..cb415ab 100644
--- a/src/initrd/btrfs-create.sh
+++ b/src/initrd/btrfs-create.sh
@@ -286,10 +286,14 @@ open_samizdat()
   fi
   modprobe btrfs || return
   btrfs device scan -u || true
-  btrfs device scan || return
-  if ! btrfs device ready "$blockdev"
+  if ! btrfs device scan || ! btrfs device ready "$blockdev"
   then
-      : btrfs device ready failed, continuing anyway
+      devcount=$(btrfs inspect-internal dump-super "$blockdev" | grep -c dev_item.devid)
+      if [ "$devcount" -eq 1 ]
+      then
+          btrfstune -m "$blockdev"
+          btrfs device ready "$blockdev" || : get used to disappointment
+      fi
   fi
   mount -t btrfs "$blockdev" /root || return
   samizdat_movemounts "$imgfile"