Re: [PATCH 7/13: eCryptfs] Dentry operations

From: Timothy R. Chavez
Date: Fri May 05 2006 - 12:46:39 EST


On Wed, 2006-05-03 at 21:39 -0600, Phillip Hellewell wrote:
> This is the 7th patch in a series of 13 constituting the kernel
> components of the eCryptfs cryptographic filesystem.
>
> eCryptfs dentry operations.
>
> Signed-off-by: Phillip Hellewell <phillip@xxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Michael Halcrow <mhalcrow@xxxxxxxxxx>
>

Hello,

Just two really really trivial comments for you all.

-tim

> ---
>
> dentry.c | 91 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 91 insertions(+)
>
> Index: linux-2.6.17-rc3-mm1-ecryptfs/fs/ecryptfs/dentry.c
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6.17-rc3-mm1-ecryptfs/fs/ecryptfs/dentry.c 2006-05-02 19:36:00.000000000 -0600
> @@ -0,0 +1,91 @@
> +/**
> + * eCryptfs: Linux filesystem encryption layer
> + *
> + * Copyright (C) 1997-2003 Erez Zadok
> + * Copyright (C) 2001-2003 Stony Brook University
> + * Copyright (C) 2004-2006 International Business Machines Corp.
> + * Author(s): Michael A. Halcrow <mahalcro@xxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of the
> + * License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
> + * 02111-1307, USA.
> + */
> +
> +#include <linux/dcache.h>
> +#include <linux/namei.h>
> +#include "ecryptfs_kernel.h"
> +
> +/**
> + * Called when the VFS needs to revalidate a dentry. This
> + * is called whenever a name lookup finds a dentry in the
> + * dcache. Most filesystems leave this as NULL, because all their
> + * dentries in the dcache are valid.
> + *
> + * @param dentry ecryptfs dentry
> + * @param nd
> + * @return 1 if valid, 0 otherwise
> + */
> +static int ecryptfs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
> +{
> + int err = 1;
> + struct dentry *lower_dentry;
> + struct dentry *saved_dentry;
> + struct vfsmount *saved_vfsmount;
> +
> + ecryptfs_printk(KERN_DEBUG, "Enter; dentry->d_name.name = [%s]\n",
> + dentry->d_name.name);
> + lower_dentry = ECRYPTFS_DENTRY_TO_LOWER(dentry);
> + if (!lower_dentry) {
> + err = 0;
> + goto out;
> + }
> + if (!lower_dentry->d_op || !lower_dentry->d_op->d_revalidate)
> + goto out;
> + saved_dentry = nd->dentry;
> + saved_vfsmount = nd->mnt;
> + nd->dentry = lower_dentry;
> + nd->mnt = ECRYPTFS_SUPERBLOCK_TO_PRIVATE(dentry->d_sb)->lower_mnt;
> + err = lower_dentry->d_op->d_revalidate(lower_dentry, nd);
> + nd->dentry = saved_dentry;
> + nd->mnt = saved_vfsmount;
> +out:
> + ecryptfs_printk(KERN_DEBUG, "Exit; err = [%d]\n", err);
> + return err;
> +}
> +
> +kmem_cache_t *ecryptfs_dentry_info_cache;

Can this be made static?

[..]
> +
> +/**
> + * Called when a dentry is really deallocated.
> + */
> +static void ecryptfs_d_release(struct dentry *dentry)
> +{
> + struct dentry *lower_dentry;
> +
> + ecryptfs_printk(KERN_DEBUG, "Enter; dentry->d_name->name = [%s]\n",
> + dentry->d_name.name);

Such a stupid thing to point out, I know, but ecryptfs_printk reports
dentry->d_name->name, when it should be dentry->d_name.name *cough* :)

> + lower_dentry = ECRYPTFS_DENTRY_TO_LOWER(dentry);
> + if (ECRYPTFS_DENTRY_TO_PRIVATE(dentry))
> + kmem_cache_free(ecryptfs_dentry_info_cache,
> + ECRYPTFS_DENTRY_TO_PRIVATE(dentry));
> + if (lower_dentry)
> + dput(lower_dentry);
> + ecryptfs_printk(KERN_DEBUG, "Exit\n");
> + return;
> +}
> +
> +struct dentry_operations ecryptfs_dops = {
> + .d_revalidate = ecryptfs_d_revalidate,
> + .d_release = ecryptfs_d_release,
> +};
> -
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