[PATCH v2] expand-on-first-boot: support resizing a btrfs root

[Joe MacDonald <joe_macdonald@mentor.com>]

resize2fs fails if the build sets the root filesystem for an image to
btrfs though the partition is expanded properly. Since the rest of the
script works as intended, simply checking the last partition type with
lsblk and adding `btrfs resize` instead of `resize2fs` in the appropriate
circumstance allows everything to function as expected.

Signed-off-by: Joe MacDonald <joe_macdonald@mentor.com>
---
 .../files/expand-last-partition.sh            | 22 ++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/meta/recipes-support/expand-on-first-boot/files/expand-last-partition.sh b/meta/recipes-support/expand-on-first-boot/files/expand-last-partition.sh
index 7175dfd..6975d9c 100755
--- a/meta/recipes-support/expand-on-first-boot/files/expand-last-partition.sh
+++ b/meta/recipes-support/expand-on-first-boot/files/expand-last-partition.sh
@@ -36,8 +36,20 @@ sfdisk -d "${BOOT_DEV}" 2>/dev/null | \
 # Inform the kernel about the partitioning change
 partx -u "${LAST_PART}"
 
-# Do not fail resize2fs if no mtab entry is found, e.g.,
-# when using systemd mount units.
-export EXT2FS_NO_MTAB_OK=1
-
-resize2fs "${LAST_PART}"
+# Determine the filesystem type and perform the appropriate resize function
+ROOTFS_TYPE=$(lsblk -fno FSTYPE ${ROOT_DEV})
+case ${ROOTFS_TYPE} in
+   ext* )
+      # Do not fail resize2fs if no mtab entry is found, e.g.,
+      # when using systemd mount units.
+      export EXT2FS_NO_MTAB_OK=1
+      resize2fs "${LAST_PART}"
+      ;;
+   btrfs )
+      btrfs filesystem resize max /
+      ;;
+   * )
+      echo "Unrecognized filesystem type ${ROOTFS_TYPE} - no resize performed"
+      exit 1
+      ;;
+esac
-- 
2.30.2