fstab: Add ext4 cache partition

Without BOARD_CACHEIMAGE_FILE_SYSTEM_TYPE, in Replicant 11,
when running 'make otapackage' we have the following build
failure:
  2021-10-06 17:37:04 - blockimgdiff.py - INFO    : Finding transfers...
  Traceback (most recent call last):
    File "[...]/out/host/linux-x86/bin/ota_from_target_files/internal/stdlib/runpy.py", line 174, in _run_module_as_main
    File "[...]/out/host/linux-x86/bin/ota_from_target_files/internal/stdlib/runpy.py", line 72, in _run_code
    File "[...]/out/host/linux-x86/bin/ota_from_target_files/__main__.py", line 12, in <module>
    File "[...]/out/host/linux-x86/bin/ota_from_target_files/internal/stdlib/runpy.py", line 174, in _run_module_as_main
    File "[...]/out/host/linux-x86/bin/ota_from_target_files/internal/stdlib/runpy.py", line 72, in _run_code
    File "[...]/out/host/linux-x86/bin/ota_from_target_files/ota_from_target_files.py", line 2258, in <module>
    File "[...]/out/host/linux-x86/bin/ota_from_target_files/ota_from_target_files.py", line 2237, in main
    File "[...]/out/host/linux-x86/bin/ota_from_target_files/ota_from_target_files.py", line 1980, in GenerateNonAbOtaPackage
    File "[...]/out/host/linux-x86/bin/ota_from_target_files/ota_from_target_files.py", line 755, in WriteFullOTAPackage
    File "[...]/out/host/linux-x86/bin/ota_from_target_files/ota_from_target_files.py", line 679, in GetBlockDifferences
    File "[...]/out/host/linux-x86/bin/ota_from_target_files/common.py", line 2630, in __init__
    File "[...]/out/host/linux-x86/bin/ota_from_target_files/blockimgdiff.py", line 342, in Compute
    File "[...]/out/host/linux-x86/bin/ota_from_target_files/blockimgdiff.py", line 1561, in FindTransfers
  AssertionError
  17:37:04 ninja failed with: exit status 1
This is because for some reasons the cache_size variable is
None. I've not been able to track exactly why though.

And with BOARD_CACHEIMAGE_FILE_SYSTEM_TYPE but without the
entry in fstab, in Replicant 11, also when running
'make otapackage' we have the following build failure:
    Traceback (most recent call last):
      File "[...]/out/host/linux-x86/bin/add_img_to_target_files/internal/stdlib/runpy.py", line 174, in _run_module_as_main
      File "[...]/out/host/linux-x86/bin/add_img_to_target_files/internal/stdlib/runpy.py", line 72, in _run_code
      File "[...]/out/host/linux-x86/bin/add_img_to_target_files/__main__.py", line 12, in <module>
      File "[...]/out/host/linux-x86/bin/add_img_to_target_files/internal/stdlib/runpy.py", line 174, in _run_module_as_main
      File "[...]/out/host/linux-x86/bin/add_img_to_target_files/internal/stdlib/runpy.py", line 72, in _run_code
      File "[...]/out/host/linux-x86/bin/add_img_to_target_files/add_img_to_target_files.py", line 999, in <module>
      File "[...]/out/host/linux-x86/bin/add_img_to_target_files/add_img_to_target_files.py", line 993, in main
      File "[...]/out/host/linux-x86/bin/add_img_to_target_files/add_img_to_target_files.py", line 876, in AddImagesToTargetFiles
      File "[...]/out/host/linux-x86/bin/add_img_to_target_files/add_img_to_target_files.py", line 539, in AddCache
      File "[...]/out/host/linux-x86/bin/add_img_to_target_files/common.py", line 1872, in CheckSize
    KeyError: '/cache'
    17:05:43 ninja failed with: exit status 1

In Replicant 6, f2fs is being used, and we have the
following in rootdir/fstab.smdk4x12 in device/samsung/i9300:
  /dev/block/mmcblk0p8            /cache                  f2fs            noatime,discard,inline_xattr,inline_data,nosuid,nodev           wait
  /dev/block/mmcblk0p8            /cache                  ext4            noatime,nosuid,nodev,journal_async_commit,errors=panic          wait

But for now ext4 is used instead of f2fs as ext4 is already
been used for and tested with the system and data
partitions, so the diff is smaller than with f2fs.

If it works fine we could then switch to f2fs (and spot
regressions if there are som):
- to stay compatible with Replicant 6
- because a log-structured file system seems more adapted
  for cache than regular filesystems like ext4.

And even if f2fs design is more recent than ext4, and that
increases the risk of loosing data, the cache partion can
easily be reformated in the recovery.

Signed-off-by: Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org>

2 files changed, 2 insertions, 0 deletions

diff --git a/BoardConfig.mk b/BoardConfig.mk
index 994bf48..e56e4ca 100644
--- a/BoardConfig.mk
+++ b/BoardConfig.mk
@@ -27,6 +27,7 @@ BOARD_RECOVERYIMAGE_PARTITION_SIZE := 8388608
 BOARD_SYSTEMIMAGE_PARTITION_SIZE := 1610612736
 # TODO: figure out if it is possible to increase USERDATA partition size
 BOARD_USERDATAIMAGE_PARTITION_SIZE := 11378320
+BOARD_CACHEIMAGE_FILE_SYSTEM_TYPE := ext4
 BOARD_CACHEIMAGE_PARTITION_SIZE := 1073741824
 BOARD_BOOTIMAGE_PARTITION_SIZE := 8388608
 BOARD_FLASH_BLOCK_SIZE := 512
diff --git a/fstab.smdk4x12 b/fstab.smdk4x12
index 303c47e..a72387d 100644
--- a/fstab.smdk4x12
+++ b/fstab.smdk4x12
@@ -15,6 +15,7 @@
 #
 
 /dev/block/platform/soc/12550000.mmc/by-name/SYSTEM	/	ext4 ro,noatime wait
+/dev/block/platform/soc/12550000.mmc/by-name/CACHE	/cache	ext4 rw,noatime,nosuid,nodev,journal_async_commit,errors=panic wait
 /dev/block/platform/soc/12550000.mmc/by-name/USERDATA	/data	ext4 rw,noatime wait
 /dev/block/platform/soc/12550000.mmc/by-name/EFS	/efs	ext4 rw,noatime wait