disk layout: allow to omit partition "start" option to start from previous partition end (#895)

* disk layout: allow to omit partition "start" option to start from previous partition end

* mixed tabs/spaces fixes

* Update filesystem.py

Co-authored-by: Anton Hvornum <anton.feeds+github@gmail.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/archinstall/lib/disk/filesystem.py b/archinstall/lib/disk/filesystem.py
index 64b8008c..c8a74e3f 100644
--- a/archinstall/lib/disk/filesystem.py
+++ b/archinstall/lib/disk/filesystem.py
@@ -18,6 +18,11 @@ from ..storage import storage
 GPT = 0b00000001
 MBR = 0b00000010
 
+# A sane default is 5MiB, that allows for plenty of buffer for GRUB on MBR
+# but also 4MiB for memory cards for instance. And another 1MiB to avoid issues.
+# (we've been pestered by disk issues since the start, so please let this be here for a few versions)
+DEFAULT_PARTITION_START = '5MiB'
+
 class Filesystem:
 	# TODO:
 	#   When instance of a HDD is selected, check all usages and gracefully unmount them
@@ -73,13 +78,16 @@ class Filesystem:
 
 			self.blockdevice.flush_cache()
 
+		prev_partition = None
 		# We then iterate the partitions in order
 		for partition in layout.get('partitions', []):
 			# We don't want to re-add an existing partition (those containing a UUID already)
 			if partition.get('wipe', False) and not partition.get('PARTUUID', None):
 				print("Adding partition....")
+				start = partition.get('start') or (
+					prev_partition and f'{prev_partition["device_instance"].end_sectors}s' or DEFAULT_PARTITION_START)
 				partition['device_instance'] = self.add_partition(partition.get('type', 'primary'),
-																	start=partition.get('start', '1MiB'), # TODO: Revisit sane block starts (4MB for memorycards for instance)
+																	start=start,
 																	end=partition.get('size', '100%'),
 																	partition_format=partition.get('filesystem', {}).get('format', 'btrfs'))
 				# TODO: device_instance some times become None
@@ -143,6 +151,8 @@ class Filesystem:
 				log(f"Marking partition {partition['device_instance']} as bootable.")
 				self.set(self.partuuid_to_index(partition['device_instance'].uuid), 'boot on')
 
+			prev_partition = partition
+
 	def find_partition(self, mountpoint :str) -> Partition:
 		for partition in self.blockdevice:
 			if partition.target_mountpoint == mountpoint or partition.mountpoint == mountpoint: