Samsung Galaxy S5 (klte): mmcblk0p23: don't know how to mount this partition

[ossilator]

it's failing at the system partition (which has a somewhat unexpectedly named mount point, i guess). if i omit it with -S, it works fine.

> tetherback -v
tetherback v0.9.1.dev20+g7797eb6_dirty
Found ADB version 1.0.41
Using default transfer method: adb exec-out pipe (--exec-out)
Device reports kernel 3.4.0-ge951bda
Device reports TWRP version 3.7.0_9-0
Reading partition map for mmcblk0 (26 partitions)...
  partition map: 100%
Reading partition map for mmcblk0rpmb (0 partitions)...
  partition map: 100%

Partition map:

BLOCK DEVICE    PARTITION NAME      SIZE (KiB)  MOUNT POINT    FSTYPE
--------------  ----------------  ------------  -------------  --------
mmcblk0p1       apnhlos                  15360
mmcblk0p2       modem                    58816
mmcblk0p3       sbl1                       512
mmcblk0p4       dbi                         64
mmcblk0p5       ddr                         32
mmcblk0p6       aboot                     2048
mmcblk0p7       rpm                        512
mmcblk0p8       tz                         512
mmcblk0p9       fsg                       3072
mmcblk0p10      pad                       7136
mmcblk0p11      param                    10240
mmcblk0p12      efs                      14336
mmcblk0p13      modemst1                  3072
mmcblk0p14      modemst2                  3072
mmcblk0p15      boot                     13312
mmcblk0p16      recovery                 15360
mmcblk0p17      fota                     13312
mmcblk0p18      backup                    7159
mmcblk0p19      fsc                          1
mmcblk0p20      ssd                          8
mmcblk0p21      persist                   8192
mmcblk0p22      persdata                  9216
mmcblk0p23      system                 2560000
mmcblk0p24      cache                   204800
mmcblk0p25      hidden                  153600
dm-0            userdata              12280815  /data          ext4
                Total:                15384559

Backup plan:

PARTITION NAME    FILENAME         FORMAT
----------------  ---------------  ------------------------------
boot              boot.emmc.win    gzipped raw image
system            system.None.win  tar -cz -p
userdata          data.ext4.win    tar -cz -p --exclude="*-cache"

Saving backup images in ./twrp-backup-2024-05-28--19-14-43/ ...
Saving partition boot (mmcblk0p15), 13 MiB uncompressed...
  boot.emmc.win: 100%   5.3 MiB/s   6.6 MiB
Traceback (most recent call last):
  File "/usr/local/bin/tetherback", line 33, in <module>
    sys.exit(load_entry_point('tetherback==0.9.1.dev20+g7797eb6.dirty', 'console_scripts', 'tetherback')())
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/dist-packages/tetherback-0.9.1.dev20+g7797eb6.dirty-py3.11.egg/tetherback/tetherback.py", line 359, in main
    backup_partition(adb, partmap[standard], bp, args.transport, backupdir, args.verify)
  File "/usr/local/lib/python3.11/dist-packages/tetherback-0.9.1.dev20+g7797eb6.dirty-py3.11.egg/tetherback/tetherback.py", line 245, in backup_partition
    raise RuntimeError(f"{pi.devname}: don't know how to mount this partition")
RuntimeError: mmcblk0p23: don't know how to mount this partition

# cat /etc/fstab
/dev/block/platform/msm_sdcc.1/by-name/modem /modem vfat rw 0 0
/dev/block/platform/msm_sdcc.1/by-name/apnhlos /firmware vfat rw 0 0
/dev/block/platform/msm_sdcc.1/by-name/system /system_root ext4 rw 0 0
/dev/block/dm-0 /data ext4 rw 0 0
/dev/block/platform/msm_sdcc.1/by-name/cache /cache ext4 rw 0 0
/dev/block/platform/msm_sdcc.1/by-name/efs /efs ext4 rw 0 0
 /external_sd vfat rw 0 0
 /usbstorage vfat rw 0 0

this looks very much like #67 (the backtrace is the same), but the root cause seems to be slightly different - note how in my case, the file system type isn't even detected correctly, and the affected partition is not device-mapped (due to not being encrypted). it's plausible that both issues would be fixed by the same fstab parser overhaul, though.