Re: [Ext2-devel] Re: ext3 htree brelse problems look to be fixed!

[Theodore Ts'o]

On Tue, Mar 04, 2003 at 06:36:54PM -0800, Christopher Li wrote:
> I post a patch for comment on ext2-devel for the
> NFS cookie bug.  Did not get any feedback yet.
> As Ted suggested, it set the cookie to -1 on EOF,
> even though it is not seek able to there.

The patch was almost good enough.  The problem with your simple
version was that on the subsequent call to ext3_dx_readdir, the -1 got
translated to a hash value of fffffffe, and if you were unlucky enough
to have a file whose hash was 0xfffffffe, you'd still end up looping
forever.

See the patch which I just sent to ext2-devel and LKML, which I think
solves both this problem and the conversion-to-htree-while-doing-NFS-readdir 
problem.   What I did was to treated f_pos==-1 as an explicit EOF cookie, 
instead of letting it get translated into large hash value.  I also explicitly 
returned a next_hash value of ~0 when there was no more leaf pages, which 
then got immediately translated into a f_pos value of -1.  This saves an 
extra call to ext3_htree_fill_tree(), a minor optimization.

						- Ted