fs/sdcardfs/main.c - kernel/msm-4.9 - Gitiles

 /*
  * fs/sdcardfs/main.c
  *
  * Copyright (c) 2013 Samsung Electronics Co. Ltd
  *   Authors: Daeho Jeong, Woojoong Lee, Seunghwan Hyun,
  *               Sunghwan Yun, Sungjong Seo
  *
  * This program has been developed as a stackable file system based on
  * the WrapFS which written by
  *
  * Copyright (c) 1998-2011 Erez Zadok
  * Copyright (c) 2009     Shrikar Archak
  * Copyright (c) 2003-2011 Stony Brook University
  * Copyright (c) 2003-2011 The Research Foundation of SUNY
  *
  * This file is dual licensed.  It may be redistributed and/or modified
  * under the terms of the Apache 2.0 License OR version 2 of the GNU
  * General Public License.
  */

 #include "sdcardfs.h"
 #include <linux/module.h>
 #include <linux/types.h>
 #include <linux/parser.h>

 enum {
 	Opt_fsuid,
 	Opt_fsgid,
 	Opt_gid,
 	Opt_debug,
 	Opt_mask,
 	Opt_multiuser,
 	Opt_userid,
 	Opt_reserved_mb,
 	Opt_err,
 };

 static const match_table_t sdcardfs_tokens = {
 	{Opt_fsuid, "fsuid=%u"},
 	{Opt_fsgid, "fsgid=%u"},
 	{Opt_gid, "gid=%u"},
 	{Opt_debug, "debug"},
 	{Opt_mask, "mask=%u"},
 	{Opt_userid, "userid=%d"},
 	{Opt_multiuser, "multiuser"},
 	{Opt_reserved_mb, "reserved_mb=%u"},
 	{Opt_err, NULL}
 };

 static int parse_options(struct super_block *sb, char *options, int silent,
 				int *debug, struct sdcardfs_vfsmount_options *vfsopts,
 				struct sdcardfs_mount_options *opts)
 {
 	char *p;
 	substring_t args[MAX_OPT_ARGS];
 	int option;

 	/* by default, we use AID_MEDIA_RW as uid, gid */
 	opts->fs_low_uid = AID_MEDIA_RW;
 	opts->fs_low_gid = AID_MEDIA_RW;
 	vfsopts->mask = 0;
 	opts->multiuser = false;
 	opts->fs_user_id = 0;
 	vfsopts->gid = 0;
 	/* by default, 0MB is reserved */
 	opts->reserved_mb = 0;

 	*debug = 0;

 	if (!options)
 		return 0;

 	while ((p = strsep(&options, ",")) != NULL) {
 		int token;

 		if (!*p)
 			continue;

 		token = match_token(p, sdcardfs_tokens, args);

 		switch (token) {
 		case Opt_debug:
 			*debug = 1;
 			break;
 		case Opt_fsuid:
 			if (match_int(&args[0], &option))
 				return 0;
 			opts->fs_low_uid = option;
 			break;
 		case Opt_fsgid:
 			if (match_int(&args[0], &option))
 				return 0;
 			opts->fs_low_gid = option;
 			break;
 		case Opt_gid:
 			if (match_int(&args[0], &option))
 				return 0;
 			vfsopts->gid = option;
 			break;
 		case Opt_userid:
 			if (match_int(&args[0], &option))
 				return 0;
 			opts->fs_user_id = option;
 			break;
 		case Opt_mask:
 			if (match_int(&args[0], &option))
 				return 0;
 			vfsopts->mask = option;
 			break;
 		case Opt_multiuser:
 			opts->multiuser = true;
 			break;
 		case Opt_reserved_mb:
 			if (match_int(&args[0], &option))
 				return 0;
 			opts->reserved_mb = option;
 			break;
 		/* unknown option */
 		default:
 			if (!silent)
 				pr_err("Unrecognized mount option \"%s\" or missing value", p);
 			return -EINVAL;
 		}
 	}

 	if (*debug) {
 		pr_info("sdcardfs : options - debug:%d\n", *debug);
 		pr_info("sdcardfs : options - uid:%d\n",
 							opts->fs_low_uid);
 		pr_info("sdcardfs : options - gid:%d\n",
 							opts->fs_low_gid);
 	}

 	return 0;
 }

 int parse_options_remount(struct super_block *sb, char *options, int silent,
 				struct sdcardfs_vfsmount_options *vfsopts)
 {
 	char *p;
 	substring_t args[MAX_OPT_ARGS];
 	int option;
 	int debug;

 	if (!options)
 		return 0;

 	while ((p = strsep(&options, ",")) != NULL) {
 		int token;

 		if (!*p)
 			continue;

 		token = match_token(p, sdcardfs_tokens, args);

 		switch (token) {
 		case Opt_debug:
 			debug = 1;
 			break;
 		case Opt_gid:
 			if (match_int(&args[0], &option))
 				return 0;
 			vfsopts->gid = option;

 			break;
 		case Opt_mask:
 			if (match_int(&args[0], &option))
 				return 0;
 			vfsopts->mask = option;
 			break;
 		case Opt_multiuser:
 		case Opt_userid:
 		case Opt_fsuid:
 		case Opt_fsgid:
 		case Opt_reserved_mb:
 			pr_warn("Option \"%s\" can't be changed during remount\n", p);
 			break;
 		/* unknown option */
 		default:
 			if (!silent)
 				pr_err("Unrecognized mount option \"%s\" or missing value", p);
 			return -EINVAL;
 		}
 	}

 	if (debug) {
 		pr_info("sdcardfs : options - debug:%d\n", debug);
 		pr_info("sdcardfs : options - gid:%d\n", vfsopts->gid);
 		pr_info("sdcardfs : options - mask:%d\n", vfsopts->mask);
 	}

 	return 0;
 }

 #if 0
 /*
  * our custom d_alloc_root work-alike
  *
  * we can't use d_alloc_root if we want to use our own interpose function
  * unchanged, so we simply call our own "fake" d_alloc_root
  */
 static struct dentry *sdcardfs_d_alloc_root(struct super_block *sb)
 {
 	struct dentry *ret = NULL;

 	if (sb) {
 		static const struct qstr name = {
 			.name = "/",
 			.len = 1
 		};

 		ret = d_alloc(NULL, &name);
 		if (ret) {
 			d_set_d_op(ret, &sdcardfs_ci_dops);
 			ret->d_sb = sb;
 			ret->d_parent = ret;
 		}
 	}
 	return ret;
 }
 #endif

 DEFINE_MUTEX(sdcardfs_super_list_lock);
 EXPORT_SYMBOL_GPL(sdcardfs_super_list_lock);
 LIST_HEAD(sdcardfs_super_list);
 EXPORT_SYMBOL_GPL(sdcardfs_super_list);

 /*
  * There is no need to lock the sdcardfs_super_info's rwsem as there is no
  * way anyone can have a reference to the superblock at this point in time.
  */
 static int sdcardfs_read_super(struct vfsmount *mnt, struct super_block *sb,
 		const char *dev_name, void *raw_data, int silent)
 {
 	int err = 0;
 	int debug;
 	struct super_block *lower_sb;
 	struct path lower_path;
 	struct sdcardfs_sb_info *sb_info;
 	struct sdcardfs_vfsmount_options *mnt_opt = mnt->data;
 	struct inode *inode;

 	pr_info("sdcardfs version 2.0\n");

 	if (!dev_name) {
 		pr_err("sdcardfs: read_super: missing dev_name argument\n");
 		err = -EINVAL;
 		goto out;
 	}

 	pr_info("sdcardfs: dev_name -> %s\n", dev_name);
 	pr_info("sdcardfs: options -> %s\n", (char *)raw_data);
 	pr_info("sdcardfs: mnt -> %p\n", mnt);

 	/* parse lower path */
 	err = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY,
 			&lower_path);
 	if (err) {
 		pr_err("sdcardfs: error accessing lower directory '%s'\n", dev_name);
 		goto out;
 	}

 	/* allocate superblock private data */
 	sb->s_fs_info = kzalloc(sizeof(struct sdcardfs_sb_info), GFP_KERNEL);
 	if (!SDCARDFS_SB(sb)) {
 		pr_crit("sdcardfs: read_super: out of memory\n");
 		err = -ENOMEM;
 		goto out_free;
 	}

 	sb_info = sb->s_fs_info;
 	/* parse options */
 	err = parse_options(sb, raw_data, silent, &debug, mnt_opt, &sb_info->options);
 	if (err) {
 		pr_err("sdcardfs: invalid options\n");
 		goto out_freesbi;
 	}

 	/* set the lower superblock field of upper superblock */
 	lower_sb = lower_path.dentry->d_sb;
 	atomic_inc(&lower_sb->s_active);
 	sdcardfs_set_lower_super(sb, lower_sb);

 	/* inherit maxbytes from lower file system */
 	sb->s_maxbytes = lower_sb->s_maxbytes;

 	/*
 	 * Our c/m/atime granularity is 1 ns because we may stack on file
 	 * systems whose granularity is as good.
 	 */
 	sb->s_time_gran = 1;

 	sb->s_magic = SDCARDFS_SUPER_MAGIC;
 	sb->s_op = &sdcardfs_sops;

 	/* get a new inode and allocate our root dentry */
 	inode = sdcardfs_iget(sb, d_inode(lower_path.dentry), 0);
 	if (IS_ERR(inode)) {
 		err = PTR_ERR(inode);
 		goto out_sput;
 	}
 	sb->s_root = d_make_root(inode);
 	if (!sb->s_root) {
 		err = -ENOMEM;
 		goto out_iput;
 	}
 	d_set_d_op(sb->s_root, &sdcardfs_ci_dops);

 	/* link the upper and lower dentries */
 	sb->s_root->d_fsdata = NULL;
 	err = new_dentry_private_data(sb->s_root);
 	if (err)
 		goto out_freeroot;

 	/* set the lower dentries for s_root */
 	sdcardfs_set_lower_path(sb->s_root, &lower_path);

 	/*
 	 * No need to call interpose because we already have a positive
 	 * dentry, which was instantiated by d_make_root.  Just need to
 	 * d_rehash it.
 	 */
 	d_rehash(sb->s_root);

 	/* setup permission policy */
 	sb_info->obbpath_s = kzalloc(PATH_MAX, GFP_KERNEL);
 	mutex_lock(&sdcardfs_super_list_lock);
 	if (sb_info->options.multiuser) {
 		setup_derived_state(d_inode(sb->s_root), PERM_PRE_ROOT,
 					sb_info->options.fs_user_id, AID_ROOT,
 					false, d_inode(sb->s_root));
 		snprintf(sb_info->obbpath_s, PATH_MAX, "%s/obb", dev_name);
 	} else {
 		setup_derived_state(d_inode(sb->s_root), PERM_ROOT,
 					sb_info->options.fs_user_id, AID_ROOT,
 					false, d_inode(sb->s_root));
 		snprintf(sb_info->obbpath_s, PATH_MAX, "%s/Android/obb", dev_name);
 	}
 	fixup_tmp_permissions(d_inode(sb->s_root));
 	sb_info->sb = sb;
 	list_add(&sb_info->list, &sdcardfs_super_list);
 	mutex_unlock(&sdcardfs_super_list_lock);

 	if (!silent)
 		pr_info("sdcardfs: mounted on top of %s type %s\n",
 				dev_name, lower_sb->s_type->name);
 	goto out; /* all is well */

 	/* no longer needed: free_dentry_private_data(sb->s_root); */
 out_freeroot:
 	dput(sb->s_root);
 out_iput:
 	iput(inode);
 out_sput:
 	/* drop refs we took earlier */
 	atomic_dec(&lower_sb->s_active);
 out_freesbi:
 	kfree(SDCARDFS_SB(sb));
 	sb->s_fs_info = NULL;
 out_free:
 	path_put(&lower_path);

 out:
 	return err;
 }

 /* A feature which supports mount_nodev() with options */
 static struct dentry *mount_nodev_with_options(struct vfsmount *mnt,
 			struct file_system_type *fs_type, int flags,
 			const char *dev_name, void *data,
 			int (*fill_super)(struct vfsmount *, struct super_block *,
 						const char *, void *, int))

 {
 	int error;
 	struct super_block *s = sget(fs_type, NULL, set_anon_super, flags, NULL);

 	if (IS_ERR(s))
 		return ERR_CAST(s);

 	s->s_flags = flags;

 	error = fill_super(mnt, s, dev_name, data, flags & MS_SILENT ? 1 : 0);
 	if (error) {
 		deactivate_locked_super(s);
 		return ERR_PTR(error);
 	}
 	s->s_flags |= MS_ACTIVE;
 	return dget(s->s_root);
 }

 static struct dentry *sdcardfs_mount(struct vfsmount *mnt,
 		struct file_system_type *fs_type, int flags,
 			    const char *dev_name, void *raw_data)
 {
 	/*
 	 * dev_name is a lower_path_name,
 	 * raw_data is a option string.
 	 */
 	return mount_nodev_with_options(mnt, fs_type, flags, dev_name,
 						raw_data, sdcardfs_read_super);
 }

 static struct dentry *sdcardfs_mount_wrn(struct file_system_type *fs_type,
 		    int flags, const char *dev_name, void *raw_data)
 {
 	WARN(1, "sdcardfs does not support mount. Use mount2.\n");
 	return ERR_PTR(-EINVAL);
 }

 void *sdcardfs_alloc_mnt_data(void)
 {
 	return kmalloc(sizeof(struct sdcardfs_vfsmount_options), GFP_KERNEL);
 }

 void sdcardfs_kill_sb(struct super_block *sb)
 {
 	struct sdcardfs_sb_info *sbi;

 	if (sb->s_magic == SDCARDFS_SUPER_MAGIC) {
 		sbi = SDCARDFS_SB(sb);
 		mutex_lock(&sdcardfs_super_list_lock);
 		list_del(&sbi->list);
 		mutex_unlock(&sdcardfs_super_list_lock);
 	}
 	generic_shutdown_super(sb);
 }

 static struct file_system_type sdcardfs_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= SDCARDFS_NAME,
 	.mount		= sdcardfs_mount_wrn,
 	.mount2		= sdcardfs_mount,
 	.alloc_mnt_data = sdcardfs_alloc_mnt_data,
 	.kill_sb	= sdcardfs_kill_sb,
 	.fs_flags	= 0,
 };
 MODULE_ALIAS_FS(SDCARDFS_NAME);

 static int __init init_sdcardfs_fs(void)
 {
 	int err;

 	pr_info("Registering sdcardfs " SDCARDFS_VERSION "\n");

 	err = sdcardfs_init_inode_cache();
 	if (err)
 		goto out;
 	err = sdcardfs_init_dentry_cache();
 	if (err)
 		goto out;
 	err = packagelist_init();
 	if (err)
 		goto out;
 	err = register_filesystem(&sdcardfs_fs_type);
 out:
 	if (err) {
 		sdcardfs_destroy_inode_cache();
 		sdcardfs_destroy_dentry_cache();
 		packagelist_exit();
 	}
 	return err;
 }

 static void __exit exit_sdcardfs_fs(void)
 {
 	sdcardfs_destroy_inode_cache();
 	sdcardfs_destroy_dentry_cache();
 	packagelist_exit();
 	unregister_filesystem(&sdcardfs_fs_type);
 	pr_info("Completed sdcardfs module unload\n");
 }

 /* Original wrapfs authors */
 MODULE_AUTHOR("Erez Zadok, Filesystems and Storage Lab, Stony Brook University (http://www.fsl.cs.sunysb.edu/)");

 /* Original sdcardfs authors */
 MODULE_AUTHOR("Woojoong Lee, Daeho Jeong, Kitae Lee, Yeongjin Gil System Memory Lab., Samsung Electronics");

 /* Current maintainer */
 MODULE_AUTHOR("Daniel Rosenberg, Google");
 MODULE_DESCRIPTION("Sdcardfs " SDCARDFS_VERSION);
 MODULE_LICENSE("GPL");

 module_init(init_sdcardfs_fs);
 module_exit(exit_sdcardfs_fs);
	/*
	* fs/sdcardfs/main.c
	*
	* Copyright (c) 2013 Samsung Electronics Co. Ltd
	* Authors: Daeho Jeong, Woojoong Lee, Seunghwan Hyun,
	* Sunghwan Yun, Sungjong Seo
	*
	* This program has been developed as a stackable file system based on
	* the WrapFS which written by
	*
	* Copyright (c) 1998-2011 Erez Zadok
	* Copyright (c) 2009 Shrikar Archak
	* Copyright (c) 2003-2011 Stony Brook University
	* Copyright (c) 2003-2011 The Research Foundation of SUNY
	*
	* This file is dual licensed. It may be redistributed and/or modified
	* under the terms of the Apache 2.0 License OR version 2 of the GNU
	* General Public License.
	*/

	#include "sdcardfs.h"
	#include <linux/module.h>
	#include <linux/types.h>
	#include <linux/parser.h>

	enum {
	Opt_fsuid,
	Opt_fsgid,
	Opt_gid,
	Opt_debug,
	Opt_mask,
	Opt_multiuser,
	Opt_userid,
	Opt_reserved_mb,
	Opt_err,
	};

	static const match_table_t sdcardfs_tokens = {
	{Opt_fsuid, "fsuid=%u"},
	{Opt_fsgid, "fsgid=%u"},
	{Opt_gid, "gid=%u"},
	{Opt_debug, "debug"},
	{Opt_mask, "mask=%u"},
	{Opt_userid, "userid=%d"},
	{Opt_multiuser, "multiuser"},
	{Opt_reserved_mb, "reserved_mb=%u"},
	{Opt_err, NULL}
	};

	static int parse_options(struct super_block sb, char options, int silent,
	int debug, struct sdcardfs_vfsmount_options vfsopts,
	struct sdcardfs_mount_options *opts)
	{
	char *p;
	substring_t args[MAX_OPT_ARGS];
	int option;

	/* by default, we use AID_MEDIA_RW as uid, gid */
	opts->fs_low_uid = AID_MEDIA_RW;
	opts->fs_low_gid = AID_MEDIA_RW;
	vfsopts->mask = 0;
	opts->multiuser = false;
	opts->fs_user_id = 0;
	vfsopts->gid = 0;
	/* by default, 0MB is reserved */
	opts->reserved_mb = 0;

	*debug = 0;

	if (!options)
	return 0;

	while ((p = strsep(&options, ",")) != NULL) {
	int token;

	if (!*p)
	continue;

	token = match_token(p, sdcardfs_tokens, args);

	switch (token) {
	case Opt_debug:
	*debug = 1;
	break;
	case Opt_fsuid:
	if (match_int(&args[0], &option))
	return 0;
	opts->fs_low_uid = option;
	break;
	case Opt_fsgid:
	if (match_int(&args[0], &option))
	return 0;
	opts->fs_low_gid = option;
	break;
	case Opt_gid:
	if (match_int(&args[0], &option))
	return 0;
	vfsopts->gid = option;
	break;
	case Opt_userid:
	if (match_int(&args[0], &option))
	return 0;
	opts->fs_user_id = option;
	break;
	case Opt_mask:
	if (match_int(&args[0], &option))
	return 0;
	vfsopts->mask = option;
	break;
	case Opt_multiuser:
	opts->multiuser = true;
	break;
	case Opt_reserved_mb:
	if (match_int(&args[0], &option))
	return 0;
	opts->reserved_mb = option;
	break;
	/* unknown option */
	default:
	if (!silent)
	pr_err("Unrecognized mount option \"%s\" or missing value", p);
	return -EINVAL;
	}
	}

	if (*debug) {
	pr_info("sdcardfs : options - debug:%d\n", *debug);
	pr_info("sdcardfs : options - uid:%d\n",
	opts->fs_low_uid);
	pr_info("sdcardfs : options - gid:%d\n",
	opts->fs_low_gid);
	}

	return 0;
	}

	int parse_options_remount(struct super_block sb, char options, int silent,
	struct sdcardfs_vfsmount_options *vfsopts)
	{
	char *p;
	substring_t args[MAX_OPT_ARGS];
	int option;
	int debug;

	if (!options)
	return 0;

	while ((p = strsep(&options, ",")) != NULL) {
	int token;

	if (!*p)
	continue;

	token = match_token(p, sdcardfs_tokens, args);

	switch (token) {
	case Opt_debug:
	debug = 1;
	break;
	case Opt_gid:
	if (match_int(&args[0], &option))
	return 0;
	vfsopts->gid = option;

	break;
	case Opt_mask:
	if (match_int(&args[0], &option))
	return 0;
	vfsopts->mask = option;
	break;
	case Opt_multiuser:
	case Opt_userid:
	case Opt_fsuid:
	case Opt_fsgid:
	case Opt_reserved_mb:
	pr_warn("Option \"%s\" can't be changed during remount\n", p);
	break;
	/* unknown option */
	default:
	if (!silent)
	pr_err("Unrecognized mount option \"%s\" or missing value", p);
	return -EINVAL;
	}
	}

	if (debug) {
	pr_info("sdcardfs : options - debug:%d\n", debug);
	pr_info("sdcardfs : options - gid:%d\n", vfsopts->gid);
	pr_info("sdcardfs : options - mask:%d\n", vfsopts->mask);
	}

	return 0;
	}

	#if 0
	/*
	* our custom d_alloc_root work-alike
	*
	* we can't use d_alloc_root if we want to use our own interpose function
	* unchanged, so we simply call our own "fake" d_alloc_root
	*/
	static struct dentry sdcardfs_d_alloc_root(struct super_block sb)
	{
	struct dentry *ret = NULL;

	if (sb) {
	static const struct qstr name = {
	.name = "/",
	.len = 1
	};

	ret = d_alloc(NULL, &name);
	if (ret) {
	d_set_d_op(ret, &sdcardfs_ci_dops);
	ret->d_sb = sb;
	ret->d_parent = ret;
	}
	}
	return ret;
	}
	#endif

	DEFINE_MUTEX(sdcardfs_super_list_lock);
	EXPORT_SYMBOL_GPL(sdcardfs_super_list_lock);
	LIST_HEAD(sdcardfs_super_list);
	EXPORT_SYMBOL_GPL(sdcardfs_super_list);

	/*
	* There is no need to lock the sdcardfs_super_info's rwsem as there is no
	* way anyone can have a reference to the superblock at this point in time.
	*/
	static int sdcardfs_read_super(struct vfsmount mnt, struct super_block sb,
	const char dev_name, void raw_data, int silent)
	{
	int err = 0;
	int debug;
	struct super_block *lower_sb;
	struct path lower_path;
	struct sdcardfs_sb_info *sb_info;
	struct sdcardfs_vfsmount_options *mnt_opt = mnt->data;
	struct inode *inode;

	pr_info("sdcardfs version 2.0\n");

	if (!dev_name) {
	pr_err("sdcardfs: read_super: missing dev_name argument\n");
	err = -EINVAL;
	goto out;
	}

	pr_info("sdcardfs: dev_name -> %s\n", dev_name);
	pr_info("sdcardfs: options -> %s\n", (char *)raw_data);
	pr_info("sdcardfs: mnt -> %p\n", mnt);

	/* parse lower path */
	err = kern_path(dev_name, LOOKUP_FOLLOW \| LOOKUP_DIRECTORY,
	&lower_path);
	if (err) {
	pr_err("sdcardfs: error accessing lower directory '%s'\n", dev_name);
	goto out;
	}

	/* allocate superblock private data */
	sb->s_fs_info = kzalloc(sizeof(struct sdcardfs_sb_info), GFP_KERNEL);
	if (!SDCARDFS_SB(sb)) {
	pr_crit("sdcardfs: read_super: out of memory\n");
	err = -ENOMEM;
	goto out_free;
	}

	sb_info = sb->s_fs_info;
	/* parse options */
	err = parse_options(sb, raw_data, silent, &debug, mnt_opt, &sb_info->options);
	if (err) {
	pr_err("sdcardfs: invalid options\n");
	goto out_freesbi;
	}

	/* set the lower superblock field of upper superblock */
	lower_sb = lower_path.dentry->d_sb;
	atomic_inc(&lower_sb->s_active);
	sdcardfs_set_lower_super(sb, lower_sb);

	/* inherit maxbytes from lower file system */
	sb->s_maxbytes = lower_sb->s_maxbytes;

	/*
	* Our c/m/atime granularity is 1 ns because we may stack on file
	* systems whose granularity is as good.
	*/
	sb->s_time_gran = 1;

	sb->s_magic = SDCARDFS_SUPER_MAGIC;
	sb->s_op = &sdcardfs_sops;

	/* get a new inode and allocate our root dentry */
	inode = sdcardfs_iget(sb, d_inode(lower_path.dentry), 0);
	if (IS_ERR(inode)) {
	err = PTR_ERR(inode);
	goto out_sput;
	}
	sb->s_root = d_make_root(inode);
	if (!sb->s_root) {
	err = -ENOMEM;
	goto out_iput;
	}
	d_set_d_op(sb->s_root, &sdcardfs_ci_dops);

	/* link the upper and lower dentries */
	sb->s_root->d_fsdata = NULL;
	err = new_dentry_private_data(sb->s_root);
	if (err)
	goto out_freeroot;

	/* set the lower dentries for s_root */
	sdcardfs_set_lower_path(sb->s_root, &lower_path);

	/*
	* No need to call interpose because we already have a positive
	* dentry, which was instantiated by d_make_root. Just need to
	* d_rehash it.
	*/
	d_rehash(sb->s_root);

	/* setup permission policy */
	sb_info->obbpath_s = kzalloc(PATH_MAX, GFP_KERNEL);
	mutex_lock(&sdcardfs_super_list_lock);
	if (sb_info->options.multiuser) {
	setup_derived_state(d_inode(sb->s_root), PERM_PRE_ROOT,
	sb_info->options.fs_user_id, AID_ROOT,
	false, d_inode(sb->s_root));
	snprintf(sb_info->obbpath_s, PATH_MAX, "%s/obb", dev_name);
	} else {
	setup_derived_state(d_inode(sb->s_root), PERM_ROOT,
	sb_info->options.fs_user_id, AID_ROOT,
	false, d_inode(sb->s_root));
	snprintf(sb_info->obbpath_s, PATH_MAX, "%s/Android/obb", dev_name);
	}
	fixup_tmp_permissions(d_inode(sb->s_root));
	sb_info->sb = sb;
	list_add(&sb_info->list, &sdcardfs_super_list);
	mutex_unlock(&sdcardfs_super_list_lock);

	if (!silent)
	pr_info("sdcardfs: mounted on top of %s type %s\n",
	dev_name, lower_sb->s_type->name);
	goto out; /* all is well */

	/* no longer needed: free_dentry_private_data(sb->s_root); */
	out_freeroot:
	dput(sb->s_root);
	out_iput:
	iput(inode);
	out_sput:
	/* drop refs we took earlier */
	atomic_dec(&lower_sb->s_active);
	out_freesbi:
	kfree(SDCARDFS_SB(sb));
	sb->s_fs_info = NULL;
	out_free:
	path_put(&lower_path);

	out:
	return err;
	}

	/* A feature which supports mount_nodev() with options */
	static struct dentry mount_nodev_with_options(struct vfsmount mnt,
	struct file_system_type *fs_type, int flags,
	const char dev_name, void data,
	int (fill_super)(struct vfsmount , struct super_block *,
	const char , void , int))

	{
	int error;
	struct super_block *s = sget(fs_type, NULL, set_anon_super, flags, NULL);

	if (IS_ERR(s))
	return ERR_CAST(s);

	s->s_flags = flags;

	error = fill_super(mnt, s, dev_name, data, flags & MS_SILENT ? 1 : 0);
	if (error) {
	deactivate_locked_super(s);
	return ERR_PTR(error);
	}
	s->s_flags \|= MS_ACTIVE;
	return dget(s->s_root);
	}

	static struct dentry sdcardfs_mount(struct vfsmount mnt,
	struct file_system_type *fs_type, int flags,
	const char dev_name, void raw_data)
	{
	/*
	* dev_name is a lower_path_name,
	* raw_data is a option string.
	*/
	return mount_nodev_with_options(mnt, fs_type, flags, dev_name,
	raw_data, sdcardfs_read_super);
	}

	static struct dentry sdcardfs_mount_wrn(struct file_system_type fs_type,
	int flags, const char dev_name, void raw_data)
	{
	WARN(1, "sdcardfs does not support mount. Use mount2.\n");
	return ERR_PTR(-EINVAL);
	}

	void *sdcardfs_alloc_mnt_data(void)
	{
	return kmalloc(sizeof(struct sdcardfs_vfsmount_options), GFP_KERNEL);
	}

	void sdcardfs_kill_sb(struct super_block *sb)
	{
	struct sdcardfs_sb_info *sbi;

	if (sb->s_magic == SDCARDFS_SUPER_MAGIC) {
	sbi = SDCARDFS_SB(sb);
	mutex_lock(&sdcardfs_super_list_lock);
	list_del(&sbi->list);
	mutex_unlock(&sdcardfs_super_list_lock);
	}
	generic_shutdown_super(sb);
	}

	static struct file_system_type sdcardfs_fs_type = {
	.owner = THIS_MODULE,
	.name = SDCARDFS_NAME,
	.mount = sdcardfs_mount_wrn,
	.mount2 = sdcardfs_mount,
	.alloc_mnt_data = sdcardfs_alloc_mnt_data,
	.kill_sb = sdcardfs_kill_sb,
	.fs_flags = 0,
	};
	MODULE_ALIAS_FS(SDCARDFS_NAME);

	static int __init init_sdcardfs_fs(void)
	{
	int err;

	pr_info("Registering sdcardfs " SDCARDFS_VERSION "\n");

	err = sdcardfs_init_inode_cache();
	if (err)
	goto out;
	err = sdcardfs_init_dentry_cache();
	if (err)
	goto out;
	err = packagelist_init();
	if (err)
	goto out;
	err = register_filesystem(&sdcardfs_fs_type);
	out:
	if (err) {
	sdcardfs_destroy_inode_cache();
	sdcardfs_destroy_dentry_cache();
	packagelist_exit();
	}
	return err;
	}

	static void __exit exit_sdcardfs_fs(void)
	{
	sdcardfs_destroy_inode_cache();
	sdcardfs_destroy_dentry_cache();
	packagelist_exit();
	unregister_filesystem(&sdcardfs_fs_type);
	pr_info("Completed sdcardfs module unload\n");
	}

	/* Original wrapfs authors */
	MODULE_AUTHOR("Erez Zadok, Filesystems and Storage Lab, Stony Brook University (http://www.fsl.cs.sunysb.edu/)");

	/* Original sdcardfs authors */
	MODULE_AUTHOR("Woojoong Lee, Daeho Jeong, Kitae Lee, Yeongjin Gil System Memory Lab., Samsung Electronics");

	/* Current maintainer */
	MODULE_AUTHOR("Daniel Rosenberg, Google");
	MODULE_DESCRIPTION("Sdcardfs " SDCARDFS_VERSION);
	MODULE_LICENSE("GPL");

	module_init(init_sdcardfs_fs);
	module_exit(exit_sdcardfs_fs);