Re: Don't use d_alloc_anon for open_by_handle

[Christoph Hellwig <hch@xxxxxxxxxxxxx>]

On Fri, May 02, 2008 at 11:55:37AM +1000, xaiki@xxxxxxx wrote:
> One of our DMAPI user found that in some cases inodes weren't getting through
> xfs_inactive() in any reasonable amount of time. Investigation tracked it down
> to the use of d_alloc_anon() combined with another thread accessing the same
> inode via an open().
> 
> So we introduce a stripped down version of d_alloc_anon, that won't try to 
> find
> an existing dentry, nor will hash it.

No, this is even more buggy than using d_alloc_anon.  What really needs
to be done in the handle code is to do the full reconnect logic nfsd
would be doing.  Aka you should be using exportfs_decode_fh and update
xfs's fh_to_dentry method to accept the file handle type used by the
handle interface.