Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750989AbWEDDi2 (ORCPT ); Wed, 3 May 2006 23:38:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750987AbWEDDi2 (ORCPT ); Wed, 3 May 2006 23:38:28 -0400 Received: from c-67-177-57-20.hsd1.ut.comcast.net ([67.177.57.20]:26602 "EHLO sshock.homelinux.net") by vger.kernel.org with ESMTP id S1750976AbWEDDi1 (ORCPT ); Wed, 3 May 2006 23:38:27 -0400 Date: Wed, 3 May 2006 21:38:29 -0600 From: Phillip Hellewell To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, viro@ftp.linux.org.uk, mike@halcrow.us, mhalcrow@us.ibm.com, mcthomps@us.ibm.com, toml@us.ibm.com, yoder1@us.ibm.com, James Morris , "Stephen C. Tweedie" , Erez Zadok , David Howells Subject: [PATCH 6/13: eCryptfs] Superblock operations Message-ID: <20060504033829.GE28613@hellewell.homeip.net> References: <20060504031755.GA28257@hellewell.homeip.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060504031755.GA28257@hellewell.homeip.net> X-URL: http://hellewell.homeip.net/ User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8562 Lines: 249 This is the 6th patch in a series of 13 constituting the kernel components of the eCryptfs cryptographic filesystem. eCryptfs superblock operations and inode allocation, deallocation, and initialization functions. Signed-off-by: Phillip Hellewell Signed-off-by: Michael Halcrow --- super.c | 225 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 225 insertions(+) Index: linux-2.6.17-rc3-mm1-ecryptfs/fs/ecryptfs/super.c =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux-2.6.17-rc3-mm1-ecryptfs/fs/ecryptfs/super.c 2006-05-02 19:36:04.000000000 -0600 @@ -0,0 +1,225 @@ +/** + * 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 + * Michael C. Thompson + * + * 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 +#include +#include +#include +#include "ecryptfs_kernel.h" + +kmem_cache_t *ecryptfs_inode_info_cache; + +/** + * Called to bring an inode into existence. + * + * Note that setting the self referencing pointer doesn't work here: + * i.e. ECRYPTFS_INODE_TO_PRIVATE_SM(inode) = ei; + * + * Only handle allocation, setting up structures should be done in + * ecryptfs_read_inode. This is because the kernel, between now and + * then, will 0 out the private data pointer. + * + * @param sb Pointer to the super block of the filesystem + * @return Pointer to a newly allocated inode, NULL otherwise + */ +static struct inode *ecryptfs_alloc_inode(struct super_block *sb) { + struct ecryptfs_inode_info *ecryptfs_inode = NULL; + struct inode *inode = NULL; + + ecryptfs_printk(KERN_DEBUG, "Enter; sb = [%p]\n", sb); + ecryptfs_inode = kmem_cache_alloc(ecryptfs_inode_info_cache, + SLAB_KERNEL); + if (unlikely(!ecryptfs_inode)) { + ecryptfs_printk(KERN_WARNING, + "Failed to allocate new inode\n"); + goto out; + } + ecryptfs_init_crypt_stat(&(ecryptfs_inode->crypt_stat)); + inode = &(ecryptfs_inode->vfs_inode); +out: + ecryptfs_printk(KERN_DEBUG, "Exit; inode = [%p]\n", inode); + return inode; +} + +/** + * This is used during the final destruction of the inode. + * All allocation of memory related to the inode, including allocated + * memory in the crypt_stat struct, will be released here. + * There should be no chance that this deallocation will be missed. + */ +static void ecryptfs_destroy_inode(struct inode *inode) { + struct ecryptfs_crypt_stat *crypt_stat; + + ecryptfs_printk(KERN_DEBUG, "Enter; inode = [%p]\n", inode); + crypt_stat = &(ECRYPTFS_INODE_TO_PRIVATE(inode))->crypt_stat; + ecryptfs_destruct_crypt_stat(crypt_stat); + kmem_cache_free(ecryptfs_inode_info_cache, + ECRYPTFS_INODE_TO_PRIVATE(inode)); + ecryptfs_printk(KERN_DEBUG, "Exit\n"); +} + +/** + * Set up the ecryptfs inode. + */ +static void ecryptfs_read_inode(struct inode *inode) +{ + ecryptfs_printk(KERN_DEBUG, "Enter; inode = [%p]\n", inode); + /* This is where we setup the self-reference in the vfs_inode's + * u.generic_ip. That way we don't have to walk the list again. */ + ECRYPTFS_INODE_TO_PRIVATE_SM(inode) = + list_entry(inode, struct ecryptfs_inode_info, vfs_inode); + ECRYPTFS_INODE_TO_LOWER(inode) = NULL; + inode->i_version++; + inode->i_op = &ecryptfs_main_iops; + inode->i_fop = &ecryptfs_main_fops; + inode->i_mapping->a_ops = &ecryptfs_aops; + ecryptfs_printk(KERN_DEBUG, "Exit\n"); +} + + +/** + * This is called through iput_final(). + * This is function will replace generic_drop_inode. The end result of which + * is we are skipping the check in inode->i_nlink, which we do not use. + */ +static void ecryptfs_drop_inode(struct inode *inode) { + generic_delete_inode(inode); +} + +/** + * Final actions when unmounting a file system. + * This will handle deallocation and release of our private data. + */ +static void ecryptfs_put_super(struct super_block *sb) +{ + struct ecryptfs_sb_info *sb_info = ECRYPTFS_SUPERBLOCK_TO_PRIVATE(sb); + + ecryptfs_printk(KERN_DEBUG, "Enter\n"); + mntput(sb_info->lower_mnt); + key_put(sb_info->mount_crypt_stat.global_auth_tok_key); + kmem_cache_free(ecryptfs_sb_info_cache, sb_info); + ECRYPTFS_SUPERBLOCK_TO_PRIVATE_SM(sb) = NULL; + ecryptfs_printk(KERN_DEBUG, "Exit\n"); +} + +/** + * Get the filesystem statistics. Currently, we let this pass right through + * to the lower filesystem and take no action ourselves. + */ +static int ecryptfs_statfs(struct super_block *sb, struct kstatfs *buf) +{ + int rc = 0; + + ecryptfs_printk(KERN_DEBUG, "Enter\n"); + rc = vfs_statfs(ECRYPTFS_SUPERBLOCK_TO_LOWER(sb), buf); + ecryptfs_printk(KERN_DEBUG, "Exit; rc = [%d]\n", rc); + return rc; +} + +/** + * Called to ask filesystem to change mount options. Not implemented; + * returns -ENOSYS every time. + */ +static int ecryptfs_remount_fs(struct super_block *sb, int *flags, char *data) +{ + ecryptfs_printk(KERN_DEBUG, "Enter\n"); + ecryptfs_printk(KERN_DEBUG, "Exit\n"); + return -ENOSYS; +} + +/** + * Called by iput() when the inode reference count reached zero + * and the inode is not hashed anywhere. Used to clear anything + * that needs to be, before the inode is completely destroyed and put + * on the inode free list. We use this to drop out reference to the + * lower inode. + */ +static void ecryptfs_clear_inode(struct inode *inode) +{ + ecryptfs_printk(KERN_DEBUG, "Enter; inode = [%p]; i_ino = [0x%.16x]\n", + inode, inode->i_ino); + iput(ECRYPTFS_INODE_TO_LOWER(inode)); + ecryptfs_printk(KERN_DEBUG, "Exit\n"); +} + +/** + * Called in do_umount() if the MNT_FORCE flag was used and this + * function is defined. See comment in linux/fs/super.c:do_umount(). + * Used only in nfs, to kill any pending RPC tasks, so that subsequent + * code can actually succeed and won't leave tasks that need handling. + */ +static void ecryptfs_umount_begin(struct vfsmount *vfsmnt, int flags) +{ + struct vfsmount *lower_mnt; + struct super_block *lower_sb; + + ecryptfs_printk(KERN_DEBUG, "Enter\n"); + lower_mnt = ECRYPTFS_SUPERBLOCK_TO_PRIVATE(vfsmnt->mnt_sb)->lower_mnt; + lower_sb = lower_mnt->mnt_sb; + if (lower_sb->s_op->umount_begin) + lower_sb->s_op->umount_begin(lower_mnt, flags); + ecryptfs_printk(KERN_DEBUG, "Exit\n"); +} + +/** + * Prints the directory we are currently mounted over + * + * @return Zero on success; non-zero otherwise + */ +static int ecryptfs_show_options(struct seq_file *m, struct vfsmount *mnt) +{ + struct super_block *sb = mnt->mnt_sb; + int rc = 0; + char *tmp = NULL; + char *path; + + ecryptfs_printk(KERN_DEBUG, "Enter\n"); + tmp = (char *)__get_free_page(GFP_KERNEL); + if (!tmp) { + rc = -ENOMEM; + goto out; + } + path = d_path(ECRYPTFS_DENTRY_TO_LOWER(sb->s_root), + ECRYPTFS_SUPERBLOCK_TO_PRIVATE(sb)->lower_mnt, tmp, + PAGE_SIZE); + seq_printf(m, ",dir=%s", path); + free_page((unsigned long)tmp); +out: + ecryptfs_printk(KERN_DEBUG, "Exit; rc = [%d]\n", rc); + return rc; +} + +struct super_operations ecryptfs_sops = { + .alloc_inode = ecryptfs_alloc_inode, + .destroy_inode = ecryptfs_destroy_inode, + .read_inode = ecryptfs_read_inode, + .drop_inode = ecryptfs_drop_inode, + .put_super = ecryptfs_put_super, + .statfs = ecryptfs_statfs, + .remount_fs = ecryptfs_remount_fs, + .clear_inode = ecryptfs_clear_inode, + .umount_begin = ecryptfs_umount_begin, + .show_options = ecryptfs_show_options +}; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/