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SubjectRe: [patch 4/4] nfs: clean up sillyrenaming in nfs_rename()
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Miklos,

Don't we need to make the 'dentry' hashed, in sillyrename case?
The d_alloc()ed dentry is unhashed, and it was d_rehash()ed later
(before the patch).

new_dentry = rehash = dentry;
:::
out:
if (rehash)
d_rehash(rehash);

Applying your patch, the 'rehash' is not re-assigned and the 'dentry'
left unhashed. Such dentry which is visible by readdir but its d_hash is
empty, will be a problem in nfs readdir (which calls d_lookup()), I am
afraid.


J. R. Okajima


Miklos Szeredi:
> The d_instantiate(new_dentry, NULL) is superfluous, the dentry is
> already negative. Rehashing this dummy dentry isn't needed either,
> d_move() works fine on an unhashed target.
>
> The re-checking for busy after a failed nfs_sillyrename() is bogus
> too: new_dentry->d_count < 2 would be a bug here.
>
> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
> ---
> fs/nfs/dir.c | 11 ++++-------
> 1 file changed, 4 insertions(+), 7 deletions(-)
>
> Index: linux-2.6/fs/nfs/dir.c
> ===================================================================
> --- linux-2.6.orig/fs/nfs/dir.c 2009-12-02 15:11:19.000000000 +0100
> +++ linux-2.6/fs/nfs/dir.c 2009-12-02 15:11:30.000000000 +0100
> @@ -1611,14 +1611,11 @@ static int nfs_rename(struct inode *old_
>
> /* silly-rename the existing target ... */
> err = nfs_sillyrename(new_dir, new_dentry);
> - if (!err) {
> - new_dentry = rehash = dentry;
> - new_inode = NULL;
> - /* instantiate the replacement target */
> - d_instantiate(new_dentry, NULL);
> - } else if (atomic_read(&new_dentry->d_count) > 1)
> - /* dentry still busy? */
> + if (err)
> goto out;
> +
> + new_dentry = dentry;
> + new_inode = NULL;
> }
> }


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