/**
 * eCryptfs: Linux filesystem encryption layer
 *
 * Copyright (C) 1997-2003 Erez Zadok
 * Copyright (C) 2001-2003 Stony Brook University
 * Copyright (C) 2004-2007 International Business Machines Corp.
 *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
 *              Michael C. Thompson <mcthomps@us.ibm.com>
 *              Tyler Hicks <tyhicks@ou.edu>
 *
 * 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/file.h>
#include <linux/module.h>
#include <linux/namei.h>
#include <linux/skbuff.h>
#include <linux/crypto.h>
#include <linux/mount.h>
#include <linux/pagemap.h>
#include <linux/key.h>
#include <linux/parser.h>
#include <linux/fs_stack.h>
#include <linux/slab.h>
#include <linux/magic.h>
#include "ecryptfs_kernel.h"

/**
 * Module parameter that defines the ecryptfs_verbosity level.
 */
int ecryptfs_verbosity = 0;

module_param(ecryptfs_verbosity, int, 0);
MODULE_PARM_DESC(ecryptfs_verbosity,
                 "Initial verbosity level (0 or 1; defaults to "
                 "0, which is Quiet)");

/**
 * Module parameter that defines the number of message buffer elements
 */
unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;

module_param(ecryptfs_message_buf_len, uint, 0);
MODULE_PARM_DESC(ecryptfs_message_buf_len,
                 "Number of message buffer elements");

/**
 * Module parameter that defines the maximum guaranteed amount of time to wait
 * for a response from ecryptfsd.  The actual sleep time will be, more than
 * likely, a small amount greater than this specified value, but only less if
 * the message successfully arrives.
 */
signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;

module_param(ecryptfs_message_wait_timeout, long, 0);
MODULE_PARM_DESC(ecryptfs_message_wait_timeout,
                 "Maximum number of seconds that an operation will "
                 "sleep while waiting for a message response from "
                 "userspace");

/**
 * Module parameter that is an estimate of the maximum number of users
 * that will be concurrently using eCryptfs. Set this to the right
 * value to balance performance and memory use.
 */
unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;

module_param(ecryptfs_number_of_users, uint, 0);
MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
                 "concurrent users of eCryptfs");

void __ecryptfs_printk(const char *fmt, ...)
{
        va_list args;
        va_start(args, fmt);
        if (fmt[1] == '7') { /* KERN_DEBUG */
                if (ecryptfs_verbosity >= 1)
                        vprintk(fmt, args);
        } else
                vprintk(fmt, args);
        va_end(args);
}

/**
 * ecryptfs_init_lower_file
 * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
 *                   the lower dentry and the lower mount set
 *
 * eCryptfs only ever keeps a single open file for every lower
 * inode. All I/O operations to the lower inode occur through that
 * file. When the first eCryptfs dentry that interposes with the first
 * lower dentry for that inode is created, this function creates the
 * lower file struct and associates it with the eCryptfs
 * inode. When all eCryptfs files associated with the inode are released, the
 * file is closed.
 *
 * The lower file will be opened with read/write permissions, if
 * possible. Otherwise, it is opened read-only.
 *
 * This function does nothing if a lower file is already
 * associated with the eCryptfs inode.
 *
 * Returns zero on success; non-zero otherwise
 */
static int ecryptfs_init_lower_file(struct dentry *dentry,
                                    struct file **lower_file)
{
        const struct cred *cred = current_cred();
        struct path *path = ecryptfs_dentry_to_lower_path(dentry);
        int rc;

        rc = ecryptfs_privileged_open(lower_file, path->dentry, path->mnt,
                                      cred);
        if (rc) {
                printk(KERN_ERR "Error opening lower file "
                       "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
                       "rc = [%d]\n", path->dentry, path->mnt, rc);
                (*lower_file) = NULL;
        }
        return rc;
}

int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode)
{
        struct ecryptfs_inode_info *inode_info;
        int count, rc = 0;

        inode_info = ecryptfs_inode_to_private(inode);
        mutex_lock(&inode_info->lower_file_mutex);
        count = atomic_inc_return(&inode_info->lower_file_count);
        if (WARN_ON_ONCE(count < 1))
                rc = -EINVAL;
        else if (count == 1) {
                rc = ecryptfs_init_lower_file(dentry,
                                              &inode_info->lower_file);
                if (rc)
                        atomic_set(&inode_info->lower_file_count, 0);
        }
        mutex_unlock(&inode_info->lower_file_mutex);
        return rc;
}

void ecryptfs_put_lower_file(struct inode *inode)
{
        struct ecryptfs_inode_info *inode_info;

        inode_info = ecryptfs_inode_to_private(inode);
        if (atomic_dec_and_mutex_lock(&inode_info->lower_file_count,
                                      &inode_info->lower_file_mutex)) {
                filemap_write_and_wait(inode->i_mapping);
                fput(inode_info->lower_file);
                inode_info->lower_file = NULL;
                mutex_unlock(&inode_info->lower_file_mutex);
        }
}

enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
       ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
       ecryptfs_opt_ecryptfs_key_bytes,
       ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
       ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
       ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
       ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only,
       ecryptfs_opt_check_dev_ruid,
       ecryptfs_opt_err };

static const match_table_t tokens = {
        {ecryptfs_opt_sig, "sig=%s"},
        {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
        {ecryptfs_opt_cipher, "cipher=%s"},
        {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
        {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
        {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
        {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
        {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
        {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
        {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
        {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
        {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
        {ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
        {ecryptfs_opt_check_dev_ruid, "ecryptfs_check_dev_ruid"},
        {ecryptfs_opt_err, NULL}
};

static int ecryptfs_init_global_auth_toks(
        struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
{
        struct ecryptfs_global_auth_tok *global_auth_tok;
        struct ecryptfs_auth_tok *auth_tok;
        int rc = 0;

        list_for_each_entry(global_auth_tok,
                            &mount_crypt_stat->global_auth_tok_list,
                            mount_crypt_stat_list) {
                rc = ecryptfs_keyring_auth_tok_for_sig(
                        &global_auth_tok->global_auth_tok_key, &auth_tok,
                        global_auth_tok->sig);
                if (rc) {
                        printk(KERN_ERR "Could not find valid key in user "
                               "session keyring for sig specified in mount "
                               "option: [%s]\n", global_auth_tok->sig);
                        global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
                        goto out;
                } else {
                        global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
                        up_write(&(global_auth_tok->global_auth_tok_key)->sem);
                }
        }
out:
        return rc;
}

static void ecryptfs_init_mount_crypt_stat(
        struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
{
        memset((void *)mount_crypt_stat, 0,
               sizeof(struct ecryptfs_mount_crypt_stat));
        INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
        mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
        mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
}

/**
 * ecryptfs_parse_options
 * @sb: The ecryptfs super block
 * @options: The options passed to the kernel
 * @check_ruid: set to 1 if device uid should be checked against the ruid
 *
 * Parse mount options:
 * debug=N         - ecryptfs_verbosity level for debug output
 * sig=XXX         - description(signature) of the key to use
 *
 * Returns the dentry object of the lower-level (lower/interposed)
 * directory; We want to mount our stackable file system on top of
 * that lower directory.
 *
 * The signature of the key to use must be the description of a key
 * already in the keyring. Mounting will fail if the key can not be
 * found.
 *
 * Returns zero on success; non-zero on error
 */
static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
                                  uid_t *check_ruid)
{
        char *p;
        int rc = 0;
        int sig_set = 0;
        int cipher_name_set = 0;
        int fn_cipher_name_set = 0;
        int cipher_key_bytes;
        int cipher_key_bytes_set = 0;
        int fn_cipher_key_bytes;
        int fn_cipher_key_bytes_set = 0;
        struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
                &sbi->mount_crypt_stat;
        substring_t args[MAX_OPT_ARGS];
        int token;
        char *sig_src;
        char *cipher_name_dst;
        char *cipher_name_src;
        char *fn_cipher_name_dst;
        char *fn_cipher_name_src;
        char *fnek_dst;
        char *fnek_src;
        char *cipher_key_bytes_src;
        char *fn_cipher_key_bytes_src;
        u8 cipher_code;

        *check_ruid = 0;

        if (!options) {
                rc = -EINVAL;
                goto out;
        }
        ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
        while ((p = strsep(&options, ",")) != NULL) {
                if (!*p)
                        continue;
                token = match_token(p, tokens, args);
                switch (token) {
                case ecryptfs_opt_sig:
                case ecryptfs_opt_ecryptfs_sig:
                        sig_src = args[0].from;
                        rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
                                                          sig_src, 0);
                        if (rc) {
                                printk(KERN_ERR "Error attempting to register "
                                       "global sig; rc = [%d]\n", rc);
                                goto out;
                        }
                        sig_set = 1;
                        break;
                case ecryptfs_opt_cipher:
                case ecryptfs_opt_ecryptfs_cipher:
                        cipher_name_src = args[0].from;
                        cipher_name_dst =
                                mount_crypt_stat->
                                global_default_cipher_name;
                        strncpy(cipher_name_dst, cipher_name_src,
                                ECRYPTFS_MAX_CIPHER_NAME_SIZE);
                        cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
                        cipher_name_set = 1;
                        break;
                case ecryptfs_opt_ecryptfs_key_bytes:
                        cipher_key_bytes_src = args[0].from;
                        cipher_key_bytes =
                                (int)simple_strtol(cipher_key_bytes_src,
                                                   &cipher_key_bytes_src, 0);
                        mount_crypt_stat->global_default_cipher_key_size =
                                cipher_key_bytes;
                        cipher_key_bytes_set = 1;
                        break;
                case ecryptfs_opt_passthrough:
                        mount_crypt_stat->flags |=
                                ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
                        break;
                case ecryptfs_opt_xattr_metadata:
                        mount_crypt_stat->flags |=
                                ECRYPTFS_XATTR_METADATA_ENABLED;
                        break;
                case ecryptfs_opt_encrypted_view:
                        mount_crypt_stat->flags |=
                                ECRYPTFS_XATTR_METADATA_ENABLED;
                        mount_crypt_stat->flags |=
                                ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
                        break;
                case ecryptfs_opt_fnek_sig:
                        fnek_src = args[0].from;
                        fnek_dst =
                                mount_crypt_stat->global_default_fnek_sig;
                        strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
                        mount_crypt_stat->global_default_fnek_sig[
                                ECRYPTFS_SIG_SIZE_HEX] = '\0';
                        rc = ecryptfs_add_global_auth_tok(
                                mount_crypt_stat,
                                mount_crypt_stat->global_default_fnek_sig,
                                ECRYPTFS_AUTH_TOK_FNEK);
                        if (rc) {
                                printk(KERN_ERR "Error attempting to register "
                                       "global fnek sig [%s]; rc = [%d]\n",
                                       mount_crypt_stat->global_default_fnek_sig,
                                       rc);
                                goto out;
                        }
                        mount_crypt_stat->flags |=
                                (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
                                 | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
                        break;
                case ecryptfs_opt_fn_cipher:
                        fn_cipher_name_src = args[0].from;
                        fn_cipher_name_dst =
                                mount_crypt_stat->global_default_fn_cipher_name;
                        strncpy(fn_cipher_name_dst, fn_cipher_name_src,
                                ECRYPTFS_MAX_CIPHER_NAME_SIZE);
                        mount_crypt_stat->global_default_fn_cipher_name[
                                ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
                        fn_cipher_name_set = 1;
                        break;
                case ecryptfs_opt_fn_cipher_key_bytes:
                        fn_cipher_key_bytes_src = args[0].from;
                        fn_cipher_key_bytes =
                                (int)simple_strtol(fn_cipher_key_bytes_src,
                                                   &fn_cipher_key_bytes_src, 0);
                        mount_crypt_stat->global_default_fn_cipher_key_bytes =
                                fn_cipher_key_bytes;
                        fn_cipher_key_bytes_set = 1;
                        break;
                case ecryptfs_opt_unlink_sigs:
                        mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
                        break;
                case ecryptfs_opt_mount_auth_tok_only:
                        mount_crypt_stat->flags |=
                                ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
                        break;
                case ecryptfs_opt_check_dev_ruid:
                        *check_ruid = 1;
                        break;
                case ecryptfs_opt_err:
                default:
                        printk(KERN_WARNING
                               "%s: eCryptfs: unrecognized option [%s]\n",
                               __func__, p);
                }
        }
        if (!sig_set) {
                rc = -EINVAL;
                ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
                                "auth tok signature as a mount "
                                "parameter; see the eCryptfs README\n");
                goto out;
        }
        if (!cipher_name_set) {
                int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);

                BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
                strcpy(mount_crypt_stat->global_default_cipher_name,
                       ECRYPTFS_DEFAULT_CIPHER);
        }
        if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
            && !fn_cipher_name_set)
                strcpy(mount_crypt_stat->global_default_fn_cipher_name,
                       mount_crypt_stat->global_default_cipher_name);
        if (!cipher_key_bytes_set)
                mount_crypt_stat->global_default_cipher_key_size = 0;
        if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
            && !fn_cipher_key_bytes_set)
                mount_crypt_stat->global_default_fn_cipher_key_bytes =
                        mount_crypt_stat->global_default_cipher_key_size;

        cipher_code = ecryptfs_code_for_cipher_string(
                mount_crypt_stat->global_default_cipher_name,
                mount_crypt_stat->global_default_cipher_key_size);
        if (!cipher_code) {
                ecryptfs_printk(KERN_ERR,
                                "eCryptfs doesn't support cipher: %s",
                                mount_crypt_stat->global_default_cipher_name);
                rc = -EINVAL;
                goto out;
        }

        mutex_lock(&key_tfm_list_mutex);
        if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
                                 NULL)) {
                rc = ecryptfs_add_new_key_tfm(
                        NULL, mount_crypt_stat->global_default_cipher_name,
                        mount_crypt_stat->global_default_cipher_key_size);
                if (rc) {
                        printk(KERN_ERR "Error attempting to initialize "
                               "cipher with name = [%s] and key size = [%td]; "
                               "rc = [%d]\n",
                               mount_crypt_stat->global_default_cipher_name,
                               mount_crypt_stat->global_default_cipher_key_size,
                               rc);
                        rc = -EINVAL;
                        mutex_unlock(&key_tfm_list_mutex);
                        goto out;
                }
        }
        if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
            && !ecryptfs_tfm_exists(
                    mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
                rc = ecryptfs_add_new_key_tfm(
                        NULL, mount_crypt_stat->global_default_fn_cipher_name,
                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
                if (rc) {
                        printk(KERN_ERR "Error attempting to initialize "
                               "cipher with name = [%s] and key size = [%td]; "
                               "rc = [%d]\n",
                               mount_crypt_stat->global_default_fn_cipher_name,
                               mount_crypt_stat->global_default_fn_cipher_key_bytes,
                               rc);
                        rc = -EINVAL;
                        mutex_unlock(&key_tfm_list_mutex);
                        goto out;
                }
        }
        mutex_unlock(&key_tfm_list_mutex);
        rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
        if (rc)
                printk(KERN_WARNING "One or more global auth toks could not "
                       "properly register; rc = [%d]\n", rc);
out:
        return rc;
}

struct kmem_cache *ecryptfs_sb_info_cache;
static struct file_system_type ecryptfs_fs_type;

/**
 * ecryptfs_get_sb
 * @fs_type
 * @flags
 * @dev_name: The path to mount over
 * @raw_data: The options passed into the kernel
 */
static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
                        const char *dev_name, void *raw_data)
{
        struct super_block *s;
        struct ecryptfs_sb_info *sbi;
        struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
        struct ecryptfs_dentry_info *root_info;
        const char *err = "Getting sb failed";
        struct inode *inode;
        struct path path;
        uid_t check_ruid;
        int rc;

        sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
        if (!sbi) {
                rc = -ENOMEM;
                goto out;
        }

        rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
        if (rc) {
                err = "Error parsing options";
                goto out;
        }
        mount_crypt_stat = &sbi->mount_crypt_stat;

        s = sget(fs_type, NULL, set_anon_super, flags, NULL);
        if (IS_ERR(s)) {
                rc = PTR_ERR(s);
                goto out;
        }

        rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs", BDI_CAP_MAP_COPY);
        if (rc)
                goto out1;

        ecryptfs_set_superblock_private(s, sbi);
        s->s_bdi = &sbi->bdi;

        /* ->kill_sb() will take care of sbi after that point */
        sbi = NULL;
        s->s_op = &ecryptfs_sops;
        s->s_d_op = &ecryptfs_dops;

        err = "Reading sb failed";
        rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
        if (rc) {
                ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
                goto out1;
        }
        if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
                rc = -EINVAL;
                printk(KERN_ERR "Mount on filesystem of type "
                        "eCryptfs explicitly disallowed due to "
                        "known incompatibilities\n");
                goto out_free;
        }

        if (check_ruid && !uid_eq(path.dentry->d_inode->i_uid, current_uid())) {
                rc = -EPERM;
                printk(KERN_ERR "Mount of device (uid: %d) not owned by "
                       "requested user (uid: %d)\n",
                        i_uid_read(path.dentry->d_inode),
                        from_kuid(&init_user_ns, current_uid()));
                goto out_free;
        }

        ecryptfs_set_superblock_lower(s, path.dentry->d_sb);

        /**
         * Set the POSIX ACL flag based on whether they're enabled in the lower
         * mount.
         */
        s->s_flags = flags & ~MS_POSIXACL;
        s->s_flags |= path.dentry->d_sb->s_flags & MS_POSIXACL;

        /**
         * Force a read-only eCryptfs mount when:
         *   1) The lower mount is ro
         *   2) The ecryptfs_encrypted_view mount option is specified
         */
        if (path.dentry->d_sb->s_flags & MS_RDONLY ||
            mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
                s->s_flags |= MS_RDONLY;

        s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
        s->s_blocksize = path.dentry->d_sb->s_blocksize;
        s->s_magic = ECRYPTFS_SUPER_MAGIC;
        s->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;

        rc = -EINVAL;
        if (s->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
                pr_err("eCryptfs: maximum fs stacking depth exceeded\n");
                goto out_free;
        }

        inode = ecryptfs_get_inode(path.dentry->d_inode, s);
        rc = PTR_ERR(inode);
        if (IS_ERR(inode))
                goto out_free;

        s->s_root = d_make_root(inode);
        if (!s->s_root) {
                rc = -ENOMEM;
                goto out_free;
        }

        rc = -ENOMEM;
        root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
        if (!root_info)
                goto out_free;

        /* ->kill_sb() will take care of root_info */
        ecryptfs_set_dentry_private(s->s_root, root_info);
        root_info->lower_path = path;

        s->s_flags |= MS_ACTIVE;
        return dget(s->s_root);

out_free:
        path_put(&path);
out1:
        deactivate_locked_super(s);
out:
        if (sbi) {
                ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
                kmem_cache_free(ecryptfs_sb_info_cache, sbi);
        }
        printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
        return ERR_PTR(rc);
}

/**
 * ecryptfs_kill_block_super
 * @sb: The ecryptfs super block
 *
 * Used to bring the superblock down and free the private data.
 */
static void ecryptfs_kill_block_super(struct super_block *sb)
{
        struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
        kill_anon_super(sb);
        if (!sb_info)
                return;
        ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
        bdi_destroy(&sb_info->bdi);
        kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
}

static struct file_system_type ecryptfs_fs_type = {
        .owner = THIS_MODULE,
        .name = "ecryptfs",
        .mount = ecryptfs_mount,
        .kill_sb = ecryptfs_kill_block_super,
        .fs_flags = 0
};
MODULE_ALIAS_FS("ecryptfs");

/**
 * inode_info_init_once
 *
 * Initializes the ecryptfs_inode_info_cache when it is created
 */
static void
inode_info_init_once(void *vptr)
{
        struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;

        inode_init_once(&ei->vfs_inode);
}

static struct ecryptfs_cache_info {
        struct kmem_cache **cache;
        const char *name;
        size_t size;
        void (*ctor)(void *obj);
} ecryptfs_cache_infos[] = {
        {
                .cache = &ecryptfs_auth_tok_list_item_cache,
                .name = "ecryptfs_auth_tok_list_item",
                .size = sizeof(struct ecryptfs_auth_tok_list_item),
        },
        {
                .cache = &ecryptfs_file_info_cache,
                .name = "ecryptfs_file_cache",
                .size = sizeof(struct ecryptfs_file_info),
        },
        {
                .cache = &ecryptfs_dentry_info_cache,
                .name = "ecryptfs_dentry_info_cache",
                .size = sizeof(struct ecryptfs_dentry_info),
        },
        {
                .cache = &ecryptfs_inode_info_cache,
                .name = "ecryptfs_inode_cache",
                .size = sizeof(struct ecryptfs_inode_info),
                .ctor = inode_info_init_once,
        },
        {
                .cache = &ecryptfs_sb_info_cache,
                .name = "ecryptfs_sb_cache",
                .size = sizeof(struct ecryptfs_sb_info),
        },
        {
                .cache = &ecryptfs_header_cache,
                .name = "ecryptfs_headers",
                .size = PAGE_CACHE_SIZE,
        },
        {
                .cache = &ecryptfs_xattr_cache,
                .name = "ecryptfs_xattr_cache",
                .size = PAGE_CACHE_SIZE,
        },
        {
                .cache = &ecryptfs_key_record_cache,
                .name = "ecryptfs_key_record_cache",
                .size = sizeof(struct ecryptfs_key_record),
        },
        {
                .cache = &ecryptfs_key_sig_cache,
                .name = "ecryptfs_key_sig_cache",
                .size = sizeof(struct ecryptfs_key_sig),
        },
        {
                .cache = &ecryptfs_global_auth_tok_cache,
                .name = "ecryptfs_global_auth_tok_cache",
                .size = sizeof(struct ecryptfs_global_auth_tok),
        },
        {
                .cache = &ecryptfs_key_tfm_cache,
                .name = "ecryptfs_key_tfm_cache",
                .size = sizeof(struct ecryptfs_key_tfm),
        },
};

static void ecryptfs_free_kmem_caches(void)
{
        int i;

        /*
         * Make sure all delayed rcu free inodes are flushed before we
         * destroy cache.
         */
        rcu_barrier();

        for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
                struct ecryptfs_cache_info *info;

                info = &ecryptfs_cache_infos[i];
                if (*(info->cache))
                        kmem_cache_destroy(*(info->cache));
        }
}

/**
 * ecryptfs_init_kmem_caches
 *
 * Returns zero on success; non-zero otherwise
 */
static int ecryptfs_init_kmem_caches(void)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
                struct ecryptfs_cache_info *info;

                info = &ecryptfs_cache_infos[i];
                *(info->cache) = kmem_cache_create(info->name, info->size,
                                0, SLAB_HWCACHE_ALIGN, info->ctor);
                if (!*(info->cache)) {
                        ecryptfs_free_kmem_caches();
                        ecryptfs_printk(KERN_WARNING, "%s: "
                                        "kmem_cache_create failed\n",
                                        info->name);
                        return -ENOMEM;
                }
        }
        return 0;
}

static struct kobject *ecryptfs_kobj;

static ssize_t version_show(struct kobject *kobj,
                            struct kobj_attribute *attr, char *buff)
{
        return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
}

static struct kobj_attribute version_attr = __ATTR_RO(version);

static struct attribute *attributes[] = {
        &version_attr.attr,
        NULL,
};

static struct attribute_group attr_group = {
        .attrs = attributes,
};

static int do_sysfs_registration(void)
{
        int rc;

        ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
        if (!ecryptfs_kobj) {
                printk(KERN_ERR "Unable to create ecryptfs kset\n");
                rc = -ENOMEM;
                goto out;
        }
        rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
        if (rc) {
                printk(KERN_ERR
                       "Unable to create ecryptfs version attributes\n");
                kobject_put(ecryptfs_kobj);
        }
out:
        return rc;
}

static void do_sysfs_unregistration(void)
{
        sysfs_remove_group(ecryptfs_kobj, &attr_group);
        kobject_put(ecryptfs_kobj);
}

static int __init ecryptfs_init(void)
{
        int rc;

        if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
                rc = -EINVAL;
                ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
                                "larger than the host's page size, and so "
                                "eCryptfs cannot run on this system. The "
                                "default eCryptfs extent size is [%u] bytes; "
                                "the page size is [%lu] bytes.\n",
                                ECRYPTFS_DEFAULT_EXTENT_SIZE,
                                (unsigned long)PAGE_CACHE_SIZE);
                goto out;
        }
        rc = ecryptfs_init_kmem_caches();
        if (rc) {
                printk(KERN_ERR
                       "Failed to allocate one or more kmem_cache objects\n");
                goto out;
        }
        rc = do_sysfs_registration();
        if (rc) {
                printk(KERN_ERR "sysfs registration failed\n");
                goto out_free_kmem_caches;
        }
        rc = ecryptfs_init_kthread();
        if (rc) {
                printk(KERN_ERR "%s: kthread initialization failed; "
                       "rc = [%d]\n", __func__, rc);
                goto out_do_sysfs_unregistration;
        }
        rc = ecryptfs_init_messaging();
        if (rc) {
                printk(KERN_ERR "Failure occurred while attempting to "
                                "initialize the communications channel to "
                                "ecryptfsd\n");
                goto out_destroy_kthread;
        }
        rc = ecryptfs_init_crypto();
        if (rc) {
                printk(KERN_ERR "Failure whilst attempting to init crypto; "
                       "rc = [%d]\n", rc);
                goto out_release_messaging;
        }
        rc = register_filesystem(&ecryptfs_fs_type);
        if (rc) {
                printk(KERN_ERR "Failed to register filesystem\n");
                goto out_destroy_crypto;
        }
        if (ecryptfs_verbosity > 0)
                printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
                        "will be written to the syslog!\n", ecryptfs_verbosity);

        goto out;
out_destroy_crypto:
        ecryptfs_destroy_crypto();
out_release_messaging:
        ecryptfs_release_messaging();
out_destroy_kthread:
        ecryptfs_destroy_kthread();
out_do_sysfs_unregistration:
        do_sysfs_unregistration();
out_free_kmem_caches:
        ecryptfs_free_kmem_caches();
out:
        return rc;
}

static void __exit ecryptfs_exit(void)
{
        int rc;

        rc = ecryptfs_destroy_crypto();
        if (rc)
                printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
                       "rc = [%d]\n", rc);
        ecryptfs_release_messaging();
        ecryptfs_destroy_kthread();
        do_sysfs_unregistration();
        unregister_filesystem(&ecryptfs_fs_type);
        ecryptfs_free_kmem_caches();
}

MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
MODULE_DESCRIPTION("eCryptfs");

MODULE_LICENSE("GPL");

module_init(ecryptfs_init)
module_exit(ecryptfs_exit)