check ext4 magic before running next steps
- mount, e2fsck, tune2fs will all fail if magic number does not match.
- mismatch always happen for FDE and is wasting boot-up time to try
all and fail always.
- skip mount steps if it has invalid magic number and do not record
fs_stat either.
- For ext4 fs with corrupt superblock, e2fsck refuses to do anything if
superblock magic is invalid. So simply running e2fsck does not help
anyway.
bug: 36231950
Test: reboot ane check fs_mgr log from dmesg
Change-Id: I9ad9e0cd30fd074b3bbf8f450bd401b133d5771a
1 file changed