Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030323AbVKCDu7 (ORCPT ); Wed, 2 Nov 2005 22:50:59 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030329AbVKCDu7 (ORCPT ); Wed, 2 Nov 2005 22:50:59 -0500 Received: from c-67-182-200-232.hsd1.ut.comcast.net ([67.182.200.232]:34798 "EHLO sshock.homelinux.net") by vger.kernel.org with ESMTP id S1030326AbVKCDu6 (ORCPT ); Wed, 2 Nov 2005 22:50:58 -0500 Date: Wed, 2 Nov 2005 20:51:20 -0700 From: Phillip Hellewell To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Cc: phillip@hellewell.homeip.net, mike@halcrow.us, mhalcrow@us.ibm.com, mcthomps@us.ibm.com, yoder1@us.ibm.com Subject: [PATCH 6/12: eCryptfs] Superblock operations Message-ID: <20051103035120.GF3005@sshock.rn.byu.edu> References: <20051103033220.GD2772@sshock.rn.byu.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20051103033220.GD2772@sshock.rn.byu.edu> 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: 9405 Lines: 264 eCryptfs superblock operations and inode allocation/deallocation/initialization functions. Signed off by: Phillip Hellewell Signed off by: Michael Halcrow Signed off by: Michael Thompson Signed off by: Kent Yoder super.c | 246 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 246 insertions(+) --- linux-2.6.14-rc5-mm1/fs/ecryptfs/super.c 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.14-rc5-mm1-ecryptfs/fs/ecryptfs/super.c 2005-11-01 14:40:17.000000000 -0600 @@ -0,0 +1,246 @@ +/** + * eCryptfs: Linux filesystem encryption layer + * + * Copyright (c) 1997-2003 Erez Zadok + * Copyright (c) 2001-2003 Stony Brook University + * Copyright (c) 2005 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. + */ + +#ifdef HAVE_CONFIG_H +# include +#endif /* HAVE_CONFIG_H */ +#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. 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(1, KERN_NOTICE, "Enter; sb = [%p]\n", sb); + ecryptfs_inode = ecryptfs_kmem_cache_alloc(ecryptfs_inode_info_cache, + SLAB_KERNEL); + if (unlikely(!ecryptfs_inode)) { + ecryptfs_printk(1, KERN_WARNING, + "Failed to allocate new inode\n"); + goto out; + } + ecryptfs_init_crypt_stats(&(ecryptfs_inode->crypt_stats)); + inode = &(ecryptfs_inode->vfs_inode); + out: + ecryptfs_printk(1, KERN_NOTICE, "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_stats 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_stats *crypt_stats; + ecryptfs_printk(1, KERN_NOTICE, "Enter; inode = [%p]\n", inode); + crypt_stats = &(INODE_TO_PRIVATE(inode))->crypt_stats; + ecryptfs_destruct_crypt_stats(crypt_stats); + ecryptfs_kmem_cache_free(ecryptfs_inode_info_cache, + INODE_TO_PRIVATE(inode)); + ecryptfs_printk(1, KERN_NOTICE, "Exit\n"); +} + +/** + * Return a pointer to our ecryptfs_inode_info struct. + * This is specified by the kernel documentation for the alloc_inode & + * destroy_inode change. We use this function to get a handle to our + * ecryptfs specific data. + * + * @param inode The inode component of the ecryptfs_inode_info we want to find + * @return Handle to our ecryptfs_inode_info + */ +static inline struct ecryptfs_inode_info *ECRYPTFS_I(struct inode *inode) +{ + return list_entry(inode, struct ecryptfs_inode_info, vfs_inode); +} + +/** + * Set up the ecryptfs inode. + */ +static void ecryptfs_read_inode(struct inode *inode) +{ + ecryptfs_printk(1, KERN_NOTICE, "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. */ + INODE_TO_PRIVATE_SM(inode) = ECRYPTFS_I(inode); + 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(1, KERN_NOTICE, "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 = SUPERBLOCK_TO_PRIVATE(sb); + ecryptfs_printk(1, KERN_NOTICE, "Enter\n"); + mntput(sb_info->lower_mnt); + key_put(sb_info->mount_crypt_stats.global_auth_tok_key); + ecryptfs_kmem_cache_free(ecryptfs_sb_info_cache, sb_info); + SUPERBLOCK_TO_PRIVATE_SM(sb) = NULL; + ecryptfs_printk(1, KERN_NOTICE, "Exit\n"); +} + +/** + * Get the filesystem statistics. Currently, we let this pass right through + * to the lower filesystem and take no action ourselves + * + * TODO: Any stats need to be transposed? + */ +static int ecryptfs_statfs(struct super_block *sb, struct kstatfs *buf) +{ + int err = 0; + ecryptfs_printk(1, KERN_NOTICE, "Enter\n"); + err = vfs_statfs(SUPERBLOCK_TO_LOWER(sb), buf); + ecryptfs_printk(1, KERN_NOTICE, "Exit; err = [%d]\n",err); + return err; +} + +/** + * TODO: Not implemented. + * Called to ask filesystem to change mount options. + */ +static int ecryptfs_remount_fs(struct super_block *sb, int *flags, char *data) +{ + ecryptfs_printk(1, KERN_NOTICE, "Enter\n"); + ecryptfs_printk(1, KERN_NOTICE, "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. + * + * TODO: Why do we just not drop the reference to the lower inode in + * ecryptfs_destroy_inode? + */ +static void ecryptfs_clear_inode(struct inode *inode) +{ + ecryptfs_printk(1, KERN_NOTICE, "Enter; inode = [%p]; i_ino = [%lu]\n", + inode, inode->i_ino); + ecryptfs_iput(INODE_TO_LOWER(inode)); + ecryptfs_printk(1, KERN_NOTICE, "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. + * + * PS. I wonder if this is somehow useful to undo damage that was + * left in the kernel after a user level file server (such as amd) + * dies. + */ +static void ecryptfs_umount_begin(struct super_block *sb) +{ + struct super_block *lower_sb; + ecryptfs_printk(1, KERN_NOTICE, "Enter\n"); + /* TODO: Explain why we are umounting the lower superblock */ + lower_sb = SUPERBLOCK_TO_LOWER(sb); + if (lower_sb->s_op->umount_begin) + lower_sb->s_op->umount_begin(lower_sb); + ecryptfs_printk(1, KERN_NOTICE, "Exit\n"); +} + +/* TODO: Where is this normally declared? */ +int seq_printf(struct seq_file *m, const char *f, ...); + +/** + * 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 ret = 0; + char *tmp = NULL; + char *path; + ecryptfs_printk(1, KERN_NOTICE, "Enter\n"); + tmp = (char *)__get_free_page(GFP_KERNEL); + if (!tmp) { + ret = -ENOMEM; + goto out; + } + /* TODO: wrap? */ + path = d_path(DENTRY_TO_LOWER(sb->s_root), + SUPERBLOCK_TO_PRIVATE(sb)->lower_mnt, tmp, PAGE_SIZE); + seq_printf(m, ",dir=%s", path); + free_page((unsigned long)tmp); + out: + ecryptfs_printk(1, KERN_NOTICE, "Exit; ret = [%d]\n",ret); + return ret; +} + +/* TODO: Provide operations? (quota stuff, dirty, sync) */ +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/