diff --git a/fs/sdcardfs/file.c b/fs/sdcardfs/file.c
index 23f8cd7..3e60550 100644
--- a/fs/sdcardfs/file.c
+++ b/fs/sdcardfs/file.c
@@ -225,7 +225,11 @@
 	}
 
 	/* save current_cred and override it */
-	OVERRIDE_CRED(sbi, saved_cred, SDCARDFS_I(inode));
+	saved_cred = override_fsids(sbi, SDCARDFS_I(inode));
+	if (!saved_cred) {
+		err = -ENOMEM;
+		goto out_err;
+	}
 
 	file->private_data =
 		kzalloc(sizeof(struct sdcardfs_file_info), GFP_KERNEL);
@@ -251,12 +255,11 @@
 
 	if (err)
 		kfree(SDCARDFS_F(file));
-	else {
+	else
 		sdcardfs_copy_and_fix_attrs(inode, sdcardfs_lower_inode(inode));
-	}
 
 out_revert_cred:
-	REVERT_CRED(saved_cred);
+	revert_fsids(saved_cred);
 out_err:
 	dput(parent);
 	return err;
diff --git a/fs/sdcardfs/inode.c b/fs/sdcardfs/inode.c
index 68e6150..aece856 100644
--- a/fs/sdcardfs/inode.c
+++ b/fs/sdcardfs/inode.c
@@ -21,11 +21,11 @@
 #include "sdcardfs.h"
 #include <linux/fs_struct.h>
 
-/* Do not directly use this function. Use OVERRIDE_CRED() instead. */
-const struct cred * override_fsids(struct sdcardfs_sb_info* sbi, struct sdcardfs_inode_info *info)
+const struct cred *override_fsids(struct sdcardfs_sb_info* sbi,
+				struct sdcardfs_inode_info *info)
 {
-	struct cred * cred;
-	const struct cred * old_cred;
+	struct cred *cred;
+	const struct cred *old_cred;
 	uid_t uid;
 
 	cred = prepare_creds();
@@ -44,8 +44,7 @@
 	return old_cred;
 }
 
-/* Do not directly use this function, use REVERT_CRED() instead. */
-void revert_fsids(const struct cred * old_cred)
+void revert_fsids(const struct cred *old_cred)
 {
 	const struct cred * cur_cred;
 
@@ -75,7 +74,10 @@
 	}
 
 	/* save current_cred and override it */
-	OVERRIDE_CRED(SDCARDFS_SB(dir->i_sb), saved_cred, SDCARDFS_I(dir));
+	saved_cred = override_fsids(SDCARDFS_SB(dir->i_sb),
+					SDCARDFS_I(dir));
+	if (!saved_cred)
+		return -ENOMEM;
 
 	sdcardfs_get_lower_path(dentry, &lower_path);
 	lower_dentry = lower_path.dentry;
@@ -111,53 +113,11 @@
 out_unlock:
 	unlock_dir(lower_parent_dentry);
 	sdcardfs_put_lower_path(dentry, &lower_path);
-	REVERT_CRED(saved_cred);
+	revert_fsids(saved_cred);
 out_eacces:
 	return err;
 }
 
-#if 0
-static int sdcardfs_link(struct dentry *old_dentry, struct inode *dir,
-		       struct dentry *new_dentry)
-{
-	struct dentry *lower_old_dentry;
-	struct dentry *lower_new_dentry;
-	struct dentry *lower_dir_dentry;
-	u64 file_size_save;
-	int err;
-	struct path lower_old_path, lower_new_path;
-
-	OVERRIDE_CRED(SDCARDFS_SB(dir->i_sb));
-
-	file_size_save = i_size_read(d_inode(old_dentry));
-	sdcardfs_get_lower_path(old_dentry, &lower_old_path);
-	sdcardfs_get_lower_path(new_dentry, &lower_new_path);
-	lower_old_dentry = lower_old_path.dentry;
-	lower_new_dentry = lower_new_path.dentry;
-	lower_dir_dentry = lock_parent(lower_new_dentry);
-
-	err = vfs_link(lower_old_dentry, d_inode(lower_dir_dentry),
-		       lower_new_dentry, NULL);
-	if (err || !d_inode(lower_new_dentry))
-		goto out;
-
-	err = sdcardfs_interpose(new_dentry, dir->i_sb, &lower_new_path);
-	if (err)
-		goto out;
-	fsstack_copy_attr_times(dir, d_inode(lower_new_dentry));
-	fsstack_copy_inode_size(dir, d_inode(lower_new_dentry));
-	set_nlink(d_inode(old_dentry),
-		  sdcardfs_lower_inode(d_inode(old_dentry))->i_nlink);
-	i_size_write(d_inode(new_dentry), file_size_save);
-out:
-	unlock_dir(lower_dir_dentry);
-	sdcardfs_put_lower_path(old_dentry, &lower_old_path);
-	sdcardfs_put_lower_path(new_dentry, &lower_new_path);
-	REVERT_CRED();
-	return err;
-}
-#endif
-
 static int sdcardfs_unlink(struct inode *dir, struct dentry *dentry)
 {
 	int err;
@@ -177,7 +137,10 @@
 	}
 
 	/* save current_cred and override it */
-	OVERRIDE_CRED(SDCARDFS_SB(dir->i_sb), saved_cred, SDCARDFS_I(dir));
+	saved_cred = override_fsids(SDCARDFS_SB(dir->i_sb),
+						SDCARDFS_I(dir));
+	if (!saved_cred)
+		return -ENOMEM;
 
 	sdcardfs_get_lower_path(dentry, &lower_path);
 	lower_dentry = lower_path.dentry;
@@ -208,44 +171,13 @@
 	unlock_dir(lower_dir_dentry);
 	dput(lower_dentry);
 	sdcardfs_put_lower_path(dentry, &lower_path);
-	REVERT_CRED(saved_cred);
+	revert_fsids(saved_cred);
 out_eacces:
 	return err;
 }
 
-#if 0
-static int sdcardfs_symlink(struct inode *dir, struct dentry *dentry,
-			  const char *symname)
+static int touch(char *abs_path, mode_t mode)
 {
-	int err;
-	struct dentry *lower_dentry;
-	struct dentry *lower_parent_dentry = NULL;
-	struct path lower_path;
-
-	OVERRIDE_CRED(SDCARDFS_SB(dir->i_sb));
-
-	sdcardfs_get_lower_path(dentry, &lower_path);
-	lower_dentry = lower_path.dentry;
-	lower_parent_dentry = lock_parent(lower_dentry);
-
-	err = vfs_symlink(d_inode(lower_parent_dentry), lower_dentry, symname);
-	if (err)
-		goto out;
-	err = sdcardfs_interpose(dentry, dir->i_sb, &lower_path);
-	if (err)
-		goto out;
-	fsstack_copy_attr_times(dir, sdcardfs_lower_inode(dir));
-	fsstack_copy_inode_size(dir, d_inode(lower_parent_dentry));
-
-out:
-	unlock_dir(lower_parent_dentry);
-	sdcardfs_put_lower_path(dentry, &lower_path);
-	REVERT_CRED();
-	return err;
-}
-#endif
-
-static int touch(char *abs_path, mode_t mode) {
 	struct file *filp = filp_open(abs_path, O_RDWR|O_CREAT|O_EXCL|O_NOFOLLOW, mode);
 	if (IS_ERR(filp)) {
 		if (PTR_ERR(filp) == -EEXIST) {
@@ -287,7 +219,10 @@
 	}
 
 	/* save current_cred and override it */
-	OVERRIDE_CRED(SDCARDFS_SB(dir->i_sb), saved_cred, SDCARDFS_I(dir));
+	saved_cred = override_fsids(SDCARDFS_SB(dir->i_sb),
+						SDCARDFS_I(dir));
+	if (!saved_cred)
+		return -ENOMEM;
 
 	/* check disk space */
 	if (!check_min_free_space(dentry, 0, 1)) {
@@ -359,14 +294,23 @@
 
 	/* When creating /Android/data and /Android/obb, mark them as .nomedia */
 	if (make_nomedia_in_obb ||
-		((pi->perm == PERM_ANDROID) && (qstr_case_eq(&dentry->d_name, &q_data)))) {
-		REVERT_CRED(saved_cred);
-		OVERRIDE_CRED(SDCARDFS_SB(dir->i_sb), saved_cred, SDCARDFS_I(d_inode(dentry)));
+		((pi->perm == PERM_ANDROID)
+				&& (qstr_case_eq(&dentry->d_name, &q_data)))) {
+		revert_fsids(saved_cred);
+		saved_cred = override_fsids(sbi,
+					SDCARDFS_I(d_inode(dentry)));
+		if (!saved_cred) {
+			pr_err("sdcardfs: failed to set up .nomedia in %s: %d\n",
+						lower_path.dentry->d_name.name,
+						-ENOMEM);
+			goto out;
+		}
 		set_fs_pwd(current->fs, &lower_path);
 		touch_err = touch(".nomedia", 0664);
 		if (touch_err) {
-			printk(KERN_ERR "sdcardfs: failed to create .nomedia in %s: %d\n",
-							lower_path.dentry->d_name.name, touch_err);
+			pr_err("sdcardfs: failed to create .nomedia in %s: %d\n",
+						lower_path.dentry->d_name.name,
+						touch_err);
 			goto out;
 		}
 	}
@@ -376,7 +320,7 @@
 out_unlock:
 	sdcardfs_put_lower_path(dentry, &lower_path);
 out_revert:
-	REVERT_CRED(saved_cred);
+	revert_fsids(saved_cred);
 out_eacces:
 	return err;
 }
@@ -399,7 +343,10 @@
 	}
 
 	/* save current_cred and override it */
-	OVERRIDE_CRED(SDCARDFS_SB(dir->i_sb), saved_cred, SDCARDFS_I(dir));
+	saved_cred = override_fsids(SDCARDFS_SB(dir->i_sb),
+						SDCARDFS_I(dir));
+	if (!saved_cred)
+		return -ENOMEM;
 
 	/* sdcardfs_get_real_lower(): in case of remove an user's obb dentry
 	 * the dentry on the original path should be deleted. */
@@ -423,44 +370,11 @@
 out:
 	unlock_dir(lower_dir_dentry);
 	sdcardfs_put_real_lower(dentry, &lower_path);
-	REVERT_CRED(saved_cred);
+	revert_fsids(saved_cred);
 out_eacces:
 	return err;
 }
 
-#if 0
-static int sdcardfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
-			dev_t dev)
-{
-	int err;
-	struct dentry *lower_dentry;
-	struct dentry *lower_parent_dentry = NULL;
-	struct path lower_path;
-
-	OVERRIDE_CRED(SDCARDFS_SB(dir->i_sb));
-
-	sdcardfs_get_lower_path(dentry, &lower_path);
-	lower_dentry = lower_path.dentry;
-	lower_parent_dentry = lock_parent(lower_dentry);
-
-	err = vfs_mknod(d_inode(lower_parent_dentry), lower_dentry, mode, dev);
-	if (err)
-		goto out;
-
-	err = sdcardfs_interpose(dentry, dir->i_sb, &lower_path);
-	if (err)
-		goto out;
-	fsstack_copy_attr_times(dir, sdcardfs_lower_inode(dir));
-	fsstack_copy_inode_size(dir, d_inode(lower_parent_dentry));
-
-out:
-	unlock_dir(lower_parent_dentry);
-	sdcardfs_put_lower_path(dentry, &lower_path);
-	REVERT_CRED();
-	return err;
-}
-#endif
-
 /*
  * The locking rules in sdcardfs_rename are complex.  We could use a simpler
  * superblock-level name-space lock for renames and copy-ups.
@@ -488,7 +402,10 @@
 	}
 
 	/* save current_cred and override it */
-	OVERRIDE_CRED(SDCARDFS_SB(old_dir->i_sb), saved_cred, SDCARDFS_I(new_dir));
+	saved_cred = override_fsids(SDCARDFS_SB(old_dir->i_sb),
+						SDCARDFS_I(new_dir));
+	if (!saved_cred)
+		return -ENOMEM;
 
 	sdcardfs_get_real_lower(old_dentry, &lower_old_path);
 	sdcardfs_get_lower_path(new_dentry, &lower_new_path);
@@ -535,7 +452,7 @@
 	dput(lower_new_dir_dentry);
 	sdcardfs_put_real_lower(old_dentry, &lower_old_path);
 	sdcardfs_put_lower_path(new_dentry, &lower_new_path);
-	REVERT_CRED(saved_cred);
+	revert_fsids(saved_cred);
 out_eacces:
 	return err;
 }
@@ -654,32 +571,7 @@
 	if (IS_POSIXACL(inode))
 		printk(KERN_WARNING "%s: This may be undefined behavior... \n", __func__);
 	err = generic_permission(&tmp, mask);
-	/* XXX
-	 * Original sdcardfs code calls inode_permission(lower_inode,.. )
-	 * for checking inode permission. But doing such things here seems
-	 * duplicated work, because the functions called after this func,
-	 * such as vfs_create, vfs_unlink, vfs_rename, and etc,
-	 * does exactly same thing, i.e., they calls inode_permission().
-	 * So we just let they do the things.
-	 * If there are any security hole, just uncomment following if block.
-	 */
-#if 0
-	if (!err) {
-		/*
-		 * Permission check on lower_inode(=EXT4).
-		 * we check it with AID_MEDIA_RW permission
-		 */
-		struct inode *lower_inode;
-		OVERRIDE_CRED(SDCARDFS_SB(inode->sb));
-
-		lower_inode = sdcardfs_lower_inode(inode);
-		err = inode_permission(lower_inode, mask);
-
-		REVERT_CRED();
-	}
-#endif
 	return err;
-
 }
 
 static int sdcardfs_setattr_wrn(struct dentry *dentry, struct iattr *ia)
@@ -758,7 +650,10 @@
 		goto out_err;
 
 	/* save current_cred and override it */
-	OVERRIDE_CRED(SDCARDFS_SB(dentry->d_sb), saved_cred, SDCARDFS_I(inode));
+	saved_cred = override_fsids(SDCARDFS_SB(dentry->d_sb),
+						SDCARDFS_I(inode));
+	if (!saved_cred)
+		return -ENOMEM;
 
 	sdcardfs_get_lower_path(dentry, &lower_path);
 	lower_dentry = lower_path.dentry;
@@ -823,7 +718,7 @@
 
 out:
 	sdcardfs_put_lower_path(dentry, &lower_path);
-	REVERT_CRED(saved_cred);
+	revert_fsids(saved_cred);
 out_err:
 	return err;
 }
@@ -910,13 +805,6 @@
 	.setattr	= sdcardfs_setattr_wrn,
 	.setattr2	= sdcardfs_setattr,
 	.getattr	= sdcardfs_getattr,
-	/* XXX Following operations are implemented,
-	 *     but FUSE(sdcard) or FAT does not support them
-	 *     These methods are *NOT* perfectly tested.
-	.symlink	= sdcardfs_symlink,
-	.link		= sdcardfs_link,
-	.mknod		= sdcardfs_mknod,
-	 */
 };
 
 const struct inode_operations sdcardfs_main_iops = {
diff --git a/fs/sdcardfs/lookup.c b/fs/sdcardfs/lookup.c
index 6b595e8..a806926 100644
--- a/fs/sdcardfs/lookup.c
+++ b/fs/sdcardfs/lookup.c
@@ -368,7 +368,12 @@
         }
 
 	/* save current_cred and override it */
-	OVERRIDE_CRED_PTR(SDCARDFS_SB(dir->i_sb), saved_cred, SDCARDFS_I(dir));
+	saved_cred = override_fsids(SDCARDFS_SB(dir->i_sb),
+						SDCARDFS_I(dir));
+	if (!saved_cred) {
+		ret = ERR_PTR(-ENOMEM);
+		goto out_err;
+	}
 
 	sdcardfs_get_lower_path(parent, &lower_parent_path);
 
@@ -400,7 +405,7 @@
 
 out:
 	sdcardfs_put_lower_path(parent, &lower_parent_path);
-	REVERT_CRED(saved_cred);
+	revert_fsids(saved_cred);
 out_err:
 	dput(parent);
 	return ret;
diff --git a/fs/sdcardfs/sdcardfs.h b/fs/sdcardfs/sdcardfs.h
index f3cced3..a9cebd2 100644
--- a/fs/sdcardfs/sdcardfs.h
+++ b/fs/sdcardfs/sdcardfs.h
@@ -85,31 +85,6 @@
 		(x)->i_mode = ((x)->i_mode & S_IFMT) | 0775;\
 	} while (0)
 
-/* OVERRIDE_CRED() and REVERT_CRED()
- * 	OVERRID_CRED()
- * 		backup original task->cred
- * 		and modifies task->cred->fsuid/fsgid to specified value.
- *	REVERT_CRED()
- * 		restore original task->cred->fsuid/fsgid.
- * These two macro should be used in pair, and OVERRIDE_CRED() should be
- * placed at the beginning of a function, right after variable declaration.
- */
-#define OVERRIDE_CRED(sdcardfs_sbi, saved_cred, info)		\
-	saved_cred = override_fsids(sdcardfs_sbi, info);	\
-	if (!saved_cred) { return -ENOMEM; }
-
-#define OVERRIDE_CRED_PTR(sdcardfs_sbi, saved_cred, info)	\
-	saved_cred = override_fsids(sdcardfs_sbi, info);	\
-	if (!saved_cred) { return ERR_PTR(-ENOMEM); }
-
-#define REVERT_CRED(saved_cred)	revert_fsids(saved_cred)
-
-#define DEBUG_CRED()		\
-	printk("KAKJAGI: %s:%d fsuid %d fsgid %d\n", 	\
-		__FUNCTION__, __LINE__, 		\
-		(int)current->cred->fsuid, 		\
-		(int)current->cred->fsgid);
-
 /* Android 5.0 support */
 
 /* Permission mode for a specific node. Controls how file permissions