Re: [PATCH v3 04/10] fs/ntfs3: Add file operations and implementation

Al Viro
2020-08-28T15:46:02Z

On Fri, Aug 28, 2020 at 07:39:32AM -0700, Konstantin Komarov wrote:

> +static struct dentry *__ntfs_lookup(struct inode *dir, struct dentry *dentry,
> + struct ntfs_fnd *fnd)
> +{
> + struct dentry *d;
> + struct inode *inode;
> +
> + inode = dir_search(dir, &dentry->d_name, fnd);
> +
> + if (!inode) {
> + d_add(dentry, NULL);
> + d = NULL;
> + goto out;
> + }
> +
> + if (IS_ERR(inode)) {
> + d = ERR_CAST(inode);
> + goto out;
> + }
> +
> + d = d_splice_alias(inode, dentry);
> + if (IS_ERR(d)) {
> + iput(inode);
> + goto out;
> + }
> +
> +out:
> + return d;
> +}

This is bollocks. First and foremost, d_splice_alias() *does* iput() on
failure, so you've got double-put there. What's more
* d_splice_alias(ERR_PTR(err), dentry) return err
* d_splice_alias(NULL, dentry) is equivalent to d_add(dentry, NULL) and returns NULL

IOW, all that boilerplate could be replaced with one line:

return d_splice_alias(dir_search(dir, &dentry->d_name, fnd), dentry);