Re: How does NILFS2 handle directory management

[Jiro SEKIBA <jir-hfpbi5WX9J54Eiagz67IpQ@public.gmane.org>]

Hi,

At Fri, 25 Sep 2009 18:23:34 +0200,
Reinoud Zandijk wrote:

...
> The Ext3 approach also is hacky and shoe-horned. How can it even see if the
> hash table is still OK? an Ext2 system could have radically reformed and
> reformatted the dirents.

The hash table consumes entire block.  First 64 bytes of the block is
fake dirent, whose inode number is 0 (means unused).  So when ext2
(or older code which does not know hash index) will use the hash index block
for normal dirents, the first fake dirent is replaced as normal entry.

So the algorithm still be able to detect the index hash is OK or not,
by checking the fake entry still stay FAKE or not, after older code mounts
the partition.

..

Thanks,

regards,
-- 
Jiro SEKIBA <jir-hfpbi5WX9J54Eiagz67IpQ@public.gmane.org>