Re: REVIEW: zero existing secondary superblocks with mkfs.xfs -f

[Eric Sandeen <sandeen@sandeen.net>]

Barry Naujok wrote:
> On Thu, 12 Jul 2007 04:06:02 +1000, Eric Sandeen <sandeen@sandeen.net>  
> wrote:

>> +	if (sb.sb_magicnum != XFS_SB_MAGIC || sb.sb_blocksize == 0)
>> +		goto done;
>>
>> Is there any chance we'd be here if the first test weren't already true?
>>  *shrug* harmless though I guess.
> 
> It's quite easy to get there if you run mkfs.xfs -f on non-XFS
> filesystem.

Oh, duh.  Of course.

>> If something goes wrong and the old found SB is full of junk, this is
>> non-fatal, right.
> 
> Yep. Worst that will happen is the pwrite loop fails, and if so, it
> stops and exits. Maybe one subtle enhancement is to make sure the
> pwrite loop doesn't extend beyond the new filesystem size.
> 
>> Out of curiosity, why not just call verify_sb for the sanity checks
>> instead of recreating a subset of them in zero_old_xfs_structures?
> 
> Because that code is in xfs_repair and not mkfs. With mkfs.xfs, we
> don't really care if anything else in the SB is bad.

Maybe a libxfs candidate?  But, ok.  Just a thought.  :)

-Eric

> Barry.
>