Re: How were some of the lustre e2fsprogs test cases generated?

[Andreas Dilger <adilger@sun.com>]

On Feb 18, 2008  19:36 -0500, Theodore Ts'o wrote:
> One minor correction --- the clusterfs e2fsprogs extents code checks
> to see if the ee_leaf_hi field is non-zero, and complains if so.
> However, it ignores the ee_start_hi field for interior (non-leaf)
> nodes in the extent tree, and a number of tests do have non-zero
> ee_start_hi fields which cause my version of e2fsprogs to (rightly)
> complain.
> 
> If you fix this, a whole bunch of tests will fail as a result, and not
> exercise the code paths that the tests were apparently trying to
> exercise.  Which is what is causing me a bit of worry and wonder about
> how those test cases were originally generated....

The original CFS extents kernel patch had a bug where the _hi fields
were not initialized correctly to zero.  The CFS exents e2fsck
patches would clear the _hi fields in the extents and index blocks,
but I disabled that in the upstream patch submission because it will
be incorrect for 48-bit filesystems.

That's the "high_bits_ok" check in e2fsck_ext_block_verify() for error
PR_1_EXTENT_HI, that only allows the high bits when there are > 2^32
blocks in the filesystem.  It's possible I made a mistake when I added
that part of the patch, but the regression tests still passed.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.