[Ocfs2-devel] [PATCH] Track negative dentries

[Wengang Wang]

On 10-06-21 20:36, Joel Becker wrote:
> On Tue, Jun 22, 2010 at 11:23:33AM +0800, Wengang Wang wrote:
> > Actually I meant two dentries in the two run of 'ls -l'.
> > At the first run, a dentry, dentry A, is created. Because fileA doesn't exist,
> > dentry->d_inode is NULL. Then a do_revalidate() is run,
> > ocfs2_dentry_revalidate() returns "not valid" since d_inode is NULL.
> > Thus the dentry A is unhashed from cache by d_invalidate().
> > At the second run of 'ls -l', since dentry A is unhashed, there is no dentry for
> > fileA exist in dentry hash, a new dentry, dentry B, is created. The new dentry B
> > don't have any info about parent ino.
> > 
> > I found that when testing my patch for the "track negative dentries".
> > Maybe I misunderstand something?
> 
> 	When that dentry gets linked into the tree, it will point to its
> d_parent.  So the parent inode is dentryB->d_parent->d_inode.

Yes Joel, I know that link.
I meant there is no parent inode number stored on on dentryB it's self,
thus no way to compare it with dentryB->d_parent->d_inode.
We set the parent inode number info to dentryA(somewhere in d_fsdata).
But it's lost at the second 'ls -l' because dentryB is got instead of dentryA. 

regards,
wengang.