Error "failed to read inode: EOF" on small size filesystem

[mappu]

Hi, thanks for this project.

I have a small size ext4 filesystem image:
volume.ext4.zip

It was created simply by mkfs -t ext4 with default options on a 128MB loopback device. It has the 64-bit feature flag.

When listing files, this library gives EOF looking for the inode (same as #5):

• failed to list file infos: failed to get directory entries: failed to get root inode: failed to read inode: EOF

This same filesystem image can be loaded successfully with the https://github.com/dsoprea/go-ext4/ library.

Somehow the GetInodeTableLoc() returned a too high value, i'll compare it further.

[mappu]

I think the ext4.GroupDescriptor is parsed wrongly for this filesystem.

masahiro331/go-ext4-filesystem

In getInode() function

inodeAddress=2
bgd=ext4.GroupDescriptor{
  GroupDescriptor32:ext4.GroupDescriptor32{
    BlockBitmapLo:0x8000,
    InodeBitmapLo:0x20000,
    InodeTableLo:0x1999,
    FreeBlocksCountLo:0x90f1,
    FreeInodesCountLo:0x1,
    UsedDirsCountLo:0x7fea,
    Flags:0x0,
    ExcludeBitmapLo:0x1,
    BlockBitmapCsumLo:0x0,
    InodeBitmapCsumLo:0x0,
    ItableUnusedLo:0x0,
    Checksum:0x0
  },
  BlockBitmapHi:0x2000,
  InodeBitmapHi:0x2000,
  InodeTableHi:0x800,
  FreeBlocksCountHi:0x2458, 
  FreeInodesCountHi:0x6582, 
  UsedDirsCountHi:0x2459, 
  ItableUnusedHi:0x6582, 
  ExcludeBitmapHi:0xffff0001, 
  BlockBitmapCsumHi:0xef53, 
  InodeBitmapCsumHi:0x1, 
  Reserved:0x1
}

dsoprea/go-ext4

GetWithAbsoluteInode(InodeRootDirectory)
Dump()

BgBlockBitmapHi: (0)
BgBlockBitmapLo: (259)
BgChecksum: [d0d4]
BgFlags: (0)
BgFreeBlocksCountHi: (0)
BgFreeBlocksCountLo: (202)
BgFreeInodesCountHi: (0)
BgFreeInodesCountLo: (2027)
BgInodeBitmapHi: (0)
BgInodeBitmapLo: (275)
BgInodeTableHi: (0)
BgInodeTableLo: (291)
BgItableUnusedHi: (0)
BgItableUnusedLo: (2027)
BgUsedDirsCountHi: (0)
BgUsedDirsCountLo: (7)
BgExcludeBitmapHi: (0)
BgBlockBitmapCsumHi: (56393)
BgInodeBitmapCsumHi: (31456)