Re: d_splice_alias() problem.

[Neil Brown]

On Friday April 30, Nikita@xxxxxxxxxxx wrote:
> 
> Also, Al Viro pointed to me that it's not clear why DCACHE_DISCONNECTED
> dentry is DCACHE_HASHED at all. If it were unhashed, last dput (done by
> nfsd thread) would destroy it, truncating file if necessary.
> 

This causes other problems (I vaguely remember).
It means that every NFS request on such a file would cause the dentry
to be created and then destroyed.  If the filesystem is keeping state
in the dentry, this gets lost.  I think some filesystems discard
preallocated space when the dentry is destroyed.  Even if not, there
is a performance hit. 

NeilBrown
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