Re: Dealing with ext3 and sparse_super

[abeiro]

> > Making a ext3 filesystem with mkfs.ext3, and then using tune2fs -O 
> > ^sparse_super doesn't solve the problem, as parted will remain 
> > complaining about 'strange layout'.
>
> e2fsck must be run after this. As the man page says:
>
>        After  setting  or clearing sparse_super and filetype filesystem
>        features, e2fsck(8) must be run on the filesystem to return the
>        filesystem  to a consistent state.  Tune2fs will print a message
>        requesting that the system administrator run e2fsck(8) if neces-
>        sary.

I did this. e2fsck took a long time repairing filesystem, but results were the
same, parted complains about 'strange layout' even when tune2fs says
sparse_super is not enabled.

As sparse_super change the location of backup superblocks, i did some 
more tests

- Made and ext3 fs (mkfs.ext3 /dev/hdc1)
- Destroy superblock (dd if=/dev/zero of=/dev/hdc1 count=1 bs=4096)
- Find backup superblocks (e2fsck, and used some C code from mine)

I've found that I can destroy main superblock, and fsck just recovers it from
backup superblocks. But if resize a partition with parted (with or without
sparse_super enabled), then destroy main superblock, e2fsck can't recover
superblock. Where the backup superblocks go?.

This happens when blocksize is 4096 bytes; Doing the same in partitions 
below 1G
where blocksize is 1024 seems to work. libparted is still complaining about
'strange layout', but resized partitions have all their backup 
superblocks. Any
clue why this can happen?