Re: d_splice_alias() problem.

Neil Brown
2004-05-03T23:47:10Z

On Friday April 30, Nikita@Namesys.COM 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