Re: [PATCH -V14 03/11] vfs: Add open by file handle support

[Nick Piggin <npiggin@suse.de>]

On Tue, Jun 15, 2010 at 10:42:53PM +0530, Aneesh Kumar K.V wrote:
> diff --git a/fs/open.c b/fs/open.c
> index 43ac798..1c5daa3 100644
> --- a/fs/open.c
> +++ b/fs/open.c
> @@ -1168,3 +1168,201 @@ SYSCALL_DEFINE4(name_to_handle_at, int, dfd, const char __user *, name,
>  	return -ENOSYS;
>  }
>  #endif
> +
> +#ifdef CONFIG_EXPORTFS
> +static struct vfsmount *get_vfsmount_from_fd(int fd)
> +{
> +	int fput_needed;
> +	struct path *path;
> +	struct file *filep;
> +
> +	if (fd == AT_FDCWD) {
> +		struct fs_struct *fs = current->fs;
> +		read_lock(&fs->lock);
> +		path = &fs->pwd;
> +		mntget(path->mnt);
> +		read_unlock(&fs->lock);
> +	} else {
> +		filep = fget_light(fd, &fput_needed);
> +		if (!filep)
> +			return ERR_PTR(-EBADF);
> +		path = &filep->f_path;
> +		mntget(path->mnt);
> +		fput_light(filep, fput_needed);
> +	}
> +	return path->mnt;
> +}

The bulk of this this should probably be in fs/namei.c, factored with
path_init stuff if possible please.