Port of sdcardfs to 4.4

Change-Id: I25b99ecf214e72ebf6a57ec3085972542a8d7951
Signed-off-by: Daniel Rosenberg <drosen@google.com>

12 files changed, 252 insertions, 506 deletions

diff --git a/fs/sdcardfs/Kconfig b/fs/sdcardfs/Kconfig
index 657f4958e8d6..d995f3eaae6d 100644
--- a/fs/sdcardfs/Kconfig
+++ b/fs/sdcardfs/Kconfig
@@ -1,6 +1,5 @@
 config SDCARD_FS
 	tristate "sdcard file system"
-	depends on EXPERIMENTAL
 	default n
 	help
 	  Sdcardfs is based on Wrapfs file system.
diff --git a/fs/sdcardfs/dentry.c b/fs/sdcardfs/dentry.c
index 4572a5403bb2..dbbcfd091fc7 100644
--- a/fs/sdcardfs/dentry.c
+++ b/fs/sdcardfs/dentry.c
@@ -26,7 +26,7 @@
  *          0: tell VFS to invalidate dentry
  *          1: dentry is valid
  */
-static int sdcardfs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
+static int sdcardfs_d_revalidate(struct dentry *dentry, unsigned int flags)
 {
 	int err = 1;
 	struct path parent_lower_path, lower_path;
@@ -35,7 +35,7 @@ static int sdcardfs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
 	struct dentry *lower_cur_parent_dentry = NULL;
 	struct dentry *lower_dentry = NULL;
 
-	if (nd && nd->flags & LOOKUP_RCU)
+	if (flags & LOOKUP_RCU)
 		return -ECHILD;
 
 	spin_lock(&dentry->d_lock);
@@ -119,7 +119,7 @@ static void sdcardfs_d_release(struct dentry *dentry)
 }
 
 static int sdcardfs_hash_ci(const struct dentry *dentry,
-				const struct inode *inode, struct qstr *qstr)
+				struct qstr *qstr)
 {
 	/*
 	 * This function is copy of vfat_hashi.
@@ -148,8 +148,7 @@ static int sdcardfs_hash_ci(const struct dentry *dentry,
  * Case insensitive compare of two vfat names.
  */
 static int sdcardfs_cmp_ci(const struct dentry *parent,
-		const struct inode *pinode,
-		const struct dentry *dentry, const struct inode *inode,
+		const struct dentry *dentry,
 		unsigned int len, const char *str, const struct qstr *name)
 {
 	/* This function is copy of vfat_cmpi */
diff --git a/fs/sdcardfs/file.c b/fs/sdcardfs/file.c
index bcacb947c874..f9c5eaafc619 100644
--- a/fs/sdcardfs/file.c
+++ b/fs/sdcardfs/file.c
@@ -50,8 +50,8 @@ static ssize_t sdcardfs_read(struct file *file, char __user *buf,
 	err = vfs_read(lower_file, buf, count, ppos);
 	/* update our inode atime upon a successful lower read */
 	if (err >= 0)
-		fsstack_copy_attr_atime(dentry->d_inode,
-					lower_file->f_path.dentry->d_inode);
+		fsstack_copy_attr_atime(d_inode(dentry),
+					file_inode(lower_file));
 
 	return err;
 }
@@ -59,7 +59,7 @@ static ssize_t sdcardfs_read(struct file *file, char __user *buf,
 static ssize_t sdcardfs_write(struct file *file, const char __user *buf,
 			    size_t count, loff_t *ppos)
 {
-	int err = 0;
+	int err;
 	struct file *lower_file;
 	struct dentry *dentry = file->f_path.dentry;
 
@@ -73,29 +73,29 @@ static ssize_t sdcardfs_write(struct file *file, const char __user *buf,
 	err = vfs_write(lower_file, buf, count, ppos);
 	/* update our inode times+sizes upon a successful lower write */
 	if (err >= 0) {
-		fsstack_copy_inode_size(dentry->d_inode,
-					lower_file->f_path.dentry->d_inode);
-		fsstack_copy_attr_times(dentry->d_inode,
-					lower_file->f_path.dentry->d_inode);
+		fsstack_copy_inode_size(d_inode(dentry),
+					file_inode(lower_file));
+		fsstack_copy_attr_times(d_inode(dentry),
+					file_inode(lower_file));
 	}
 
 	return err;
 }
 
-static int sdcardfs_readdir(struct file *file, void *dirent, filldir_t filldir)
+static int sdcardfs_readdir(struct file *file, struct dir_context *ctx)
 {
-	int err = 0;
+	int err;
 	struct file *lower_file = NULL;
 	struct dentry *dentry = file->f_path.dentry;
 
 	lower_file = sdcardfs_lower_file(file);
 
 	lower_file->f_pos = file->f_pos;
-	err = vfs_readdir(lower_file, filldir, dirent);
+	err = iterate_dir(lower_file, ctx);
 	file->f_pos = lower_file->f_pos;
 	if (err >= 0)		/* copy the atime */
-		fsstack_copy_attr_atime(dentry->d_inode,
-					lower_file->f_path.dentry->d_inode);
+		fsstack_copy_attr_atime(d_inode(dentry),
+					file_inode(lower_file));
 	return err;
 }
 
@@ -191,7 +191,6 @@ static int sdcardfs_mmap(struct file *file, struct vm_area_struct *vma)
 	 */
 	file_accessed(file);
 	vma->vm_ops = &sdcardfs_vm_ops;
-	vma->vm_flags |= VM_CAN_NONLINEAR;
 
 	file->f_mapping->a_ops = &sdcardfs_aops; /* set our aops */
 	if (!SDCARDFS_F(file)->lower_vm_ops) /* save for our ->fault */
@@ -242,8 +241,8 @@ static int sdcardfs_open(struct inode *inode, struct file *file)
 
 	/* open lower object and link sdcardfs's file struct to lower's */
 	sdcardfs_get_lower_path(file->f_path.dentry, &lower_path);
-	lower_file = dentry_open(lower_path.dentry, lower_path.mnt,
-				 file->f_flags, current_cred());
+	lower_file = dentry_open(&lower_path, file->f_flags, current_cred());
+	path_put(&lower_path);
 	if (IS_ERR(lower_file)) {
 		err = PTR_ERR(lower_file);
 		lower_file = sdcardfs_lower_file(file);
@@ -275,8 +274,10 @@ static int sdcardfs_flush(struct file *file, fl_owner_t id)
 	struct file *lower_file = NULL;
 
 	lower_file = sdcardfs_lower_file(file);
-	if (lower_file && lower_file->f_op && lower_file->f_op->flush)
+	if (lower_file && lower_file->f_op && lower_file->f_op->flush) {
+		filemap_write_and_wait(file->f_mapping);
 		err = lower_file->f_op->flush(lower_file, id);
+	}
 
 	return err;
 }
@@ -296,19 +297,23 @@ static int sdcardfs_file_release(struct inode *inode, struct file *file)
 	return 0;
 }
 
-static int
-sdcardfs_fsync(struct file *file, int datasync)
+static int sdcardfs_fsync(struct file *file, loff_t start, loff_t end,
+			int datasync)
 {
 	int err;
 	struct file *lower_file;
 	struct path lower_path;
 	struct dentry *dentry = file->f_path.dentry;
 
+	err = __generic_file_fsync(file, start, end, datasync);
+	if (err)
+		goto out;
+
 	lower_file = sdcardfs_lower_file(file);
 	sdcardfs_get_lower_path(dentry, &lower_path);
-	err = vfs_fsync(lower_file, datasync);
+	err = vfs_fsync_range(lower_file, start, end, datasync);
 	sdcardfs_put_lower_path(dentry, &lower_path);
-
+out:
 	return err;
 }
 
@@ -344,7 +349,7 @@ const struct file_operations sdcardfs_main_fops = {
 const struct file_operations sdcardfs_dir_fops = {
 	.llseek		= generic_file_llseek,
 	.read		= generic_read_dir,
-	.readdir	= sdcardfs_readdir,
+	.iterate	= sdcardfs_readdir,
 	.unlocked_ioctl	= sdcardfs_unlocked_ioctl,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl	= sdcardfs_compat_ioctl,
diff --git a/fs/sdcardfs/hashtable.h b/fs/sdcardfs/hashtable.h
deleted file mode 100644
index 1e770f3df148..000000000000
--- a/fs/sdcardfs/hashtable.h
+++ /dev/null
@@ -1,190 +0,0 @@
-/*
- * Statically sized hash table implementation
- * (C) 2012  Sasha Levin <levinsasha928@gmail.com>
- */
-
-#ifndef _LINUX_HASHTABLE_H
-#define _LINUX_HASHTABLE_H
-
-#include <linux/list.h>
-#include <linux/types.h>
-#include <linux/kernel.h>
-#include <linux/hash.h>
-#include <linux/rculist.h>
-
-#define DEFINE_HASHTABLE(name, bits)                                            \
-        struct hlist_head name[1 << (bits)] =                                   \
-                        { [0 ... ((1 << (bits)) - 1)] = HLIST_HEAD_INIT }
-
-#define DECLARE_HASHTABLE(name, bits)                                           \
-        struct hlist_head name[1 << (bits)]
-
-#define HASH_SIZE(name) (ARRAY_SIZE(name))
-#define HASH_BITS(name) ilog2(HASH_SIZE(name))
-
-/* Use hash_32 when possible to allow for fast 32bit hashing in 64bit kernels. */
-#define hash_min(val, bits)                                                     \
-        (sizeof(val) <= 4 ? hash_32(val, bits) : hash_long(val, bits))
-
-static inline void __hash_init(struct hlist_head *ht, unsigned int sz)
-{
-        unsigned int i;
-
-        for (i = 0; i < sz; i++)
-                INIT_HLIST_HEAD(&ht[i]);
-}
-
-/**
- * hash_init - initialize a hash table
- * @hashtable: hashtable to be initialized
- *
- * Calculates the size of the hashtable from the given parameter, otherwise
- * same as hash_init_size.
- *
- * This has to be a macro since HASH_BITS() will not work on pointers since
- * it calculates the size during preprocessing.
- */
-#define hash_init(hashtable) __hash_init(hashtable, HASH_SIZE(hashtable))
-
-/**
- * hash_add - add an object to a hashtable
- * @hashtable: hashtable to add to
- * @node: the &struct hlist_node of the object to be added
- * @key: the key of the object to be added
- */
-#define hash_add(hashtable, node, key)                                          \
-        hlist_add_head(node, &hashtable[hash_min(key, HASH_BITS(hashtable))])
-
-/**
- * hash_add_rcu - add an object to a rcu enabled hashtable
- * @hashtable: hashtable to add to
- * @node: the &struct hlist_node of the object to be added
- * @key: the key of the object to be added
- */
-#define hash_add_rcu(hashtable, node, key)                                      \
-        hlist_add_head_rcu(node, &hashtable[hash_min(key, HASH_BITS(hashtable))])
-
-/**
- * hash_hashed - check whether an object is in any hashtable
- * @node: the &struct hlist_node of the object to be checked
- */
-static inline bool hash_hashed(struct hlist_node *node)
-{
-        return !hlist_unhashed(node);
-}
-
-static inline bool __hash_empty(struct hlist_head *ht, unsigned int sz)
-{
-        unsigned int i;
-
-        for (i = 0; i < sz; i++)
-                if (!hlist_empty(&ht[i]))
-                        return false;
-
-        return true;
-}
-
-/**
- * hash_empty - check whether a hashtable is empty
- * @hashtable: hashtable to check
- *
- * This has to be a macro since HASH_BITS() will not work on pointers since
- * it calculates the size during preprocessing.
- */
-#define hash_empty(hashtable) __hash_empty(hashtable, HASH_SIZE(hashtable))
-
-/**
- * hash_del - remove an object from a hashtable
- * @node: &struct hlist_node of the object to remove
- */
-static inline void hash_del(struct hlist_node *node)
-{
-        hlist_del_init(node);
-}
-
-/**
- * hash_del_rcu - remove an object from a rcu enabled hashtable
- * @node: &struct hlist_node of the object to remove
- */
-static inline void hash_del_rcu(struct hlist_node *node)
-{
-        hlist_del_init_rcu(node);
-}
-
-/**
- * hash_for_each - iterate over a hashtable
- * @name: hashtable to iterate
- * @bkt: integer to use as bucket loop cursor
- * @obj: the type * to use as a loop cursor for each entry
- * @member: the name of the hlist_node within the struct
- */
-#define hash_for_each(name, bkt, obj, member, pos)                           \
-        for ((bkt) = 0, obj = NULL; obj == NULL && (bkt) < HASH_SIZE(name);\
-                        (bkt)++)\
-                hlist_for_each_entry(obj, pos, &name[bkt], member)
-
-/**
- * hash_for_each_rcu - iterate over a rcu enabled hashtable
- * @name: hashtable to iterate
- * @bkt: integer to use as bucket loop cursor
- * @obj: the type * to use as a loop cursor for each entry
- * @member: the name of the hlist_node within the struct
- */
-#define hash_for_each_rcu(name, bkt, obj, member)                       \
-        for ((bkt) = 0, obj = NULL; obj == NULL && (bkt) < HASH_SIZE(name);\
-                        (bkt)++)\
-                hlist_for_each_entry_rcu(obj, &name[bkt], member)
-
-/**
- * hash_for_each_safe - iterate over a hashtable safe against removal of
- * hash entry
- * @name: hashtable to iterate
- * @bkt: integer to use as bucket loop cursor
- * @tmp: a &struct used for temporary storage
- * @obj: the type * to use as a loop cursor for each entry
- * @member: the name of the hlist_node within the struct
- */
-#define hash_for_each_safe(name, bkt, tmp, obj, member, pos)                 \
-        for ((bkt) = 0, obj = NULL; (bkt) < HASH_SIZE(name);\
-                        (bkt)++)\
-                hlist_for_each_entry_safe(obj, pos, tmp, &name[bkt], member)
-
-/**
- * hash_for_each_possible - iterate over all possible objects hashing to the
- * same bucket
- * @name: hashtable to iterate
- * @obj: the type * to use as a loop cursor for each entry
- * @member: the name of the hlist_node within the struct
- * @key: the key of the objects to iterate over
- */
-#define hash_for_each_possible(name, obj, member, key, pos)                  \
-        hlist_for_each_entry(obj, pos, &name[hash_min(key, HASH_BITS(name))], member)
-
-/**
- * hash_for_each_possible_rcu - iterate over all possible objects hashing to the
- * same bucket in an rcu enabled hashtable
- * in a rcu enabled hashtable
- * @name: hashtable to iterate
- * @obj: the type * to use as a loop cursor for each entry
- * @member: the name of the hlist_node within the struct
- * @key: the key of the objects to iterate over
- */
-#define hash_for_each_possible_rcu(name, obj, member, key)              \
-        hlist_for_each_entry_rcu(obj, &name[hash_min(key, HASH_BITS(name))],\
-                member)
-
-/**
- * hash_for_each_possible_safe - iterate over all possible objects hashing to the
- * same bucket safe against removals
- * @name: hashtable to iterate
- * @obj: the type * to use as a loop cursor for each entry
- * @tmp: a &struct used for temporary storage
- * @member: the name of the hlist_node within the struct
- * @key: the key of the objects to iterate over
- */
-#define hash_for_each_possible_safe(name, obj, tmp, member, key)        \
-        hlist_for_each_entry_safe(obj, tmp,\
-                &name[hash_min(key, HASH_BITS(name))], member)
-
-
-#endif
diff --git a/fs/sdcardfs/inode.c b/fs/sdcardfs/inode.c
index e8ed04250ed1..75c622bac2f5 100644
--- a/fs/sdcardfs/inode.c
+++ b/fs/sdcardfs/inode.c
@@ -30,8 +30,8 @@ const struct cred * override_fsids(struct sdcardfs_sb_info* sbi)
 	if (!cred)
 		return NULL;
 
-	cred->fsuid = sbi->options.fs_low_uid;
-	cred->fsgid = sbi->options.fs_low_gid;
+	cred->fsuid = make_kuid(&init_user_ns, sbi->options.fs_low_uid);
+	cred->fsgid = make_kgid(&init_user_ns, sbi->options.fs_low_gid);
 
 	old_cred = override_creds(cred);
 
@@ -49,12 +49,12 @@ void revert_fsids(const struct cred * old_cred)
 }
 
 static int sdcardfs_create(struct inode *dir, struct dentry *dentry,
-			 int mode, struct nameidata *nd)
+			 umode_t mode, bool want_excl)
 {
-	int err = 0;
+	int err;
 	struct dentry *lower_dentry;
 	struct dentry *lower_parent_dentry = NULL;
-	struct path lower_path, saved_path;
+	struct path lower_path;
 	struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dentry->d_sb);
 	const struct cred *saved_cred = NULL;
 
@@ -74,18 +74,9 @@ static int sdcardfs_create(struct inode *dir, struct dentry *dentry,
 	lower_dentry = lower_path.dentry;
 	lower_parent_dentry = lock_parent(lower_dentry);
 
-	err = mnt_want_write(lower_path.mnt);
-	if (err)
-		goto out_unlock;
-
-	pathcpy(&saved_path, &nd->path);
-	pathcpy(&nd->path, &lower_path);
-
 	/* set last 16bytes of mode field to 0664 */
 	mode = (mode & S_IFMT) | 00664;
-	err = vfs_create(lower_parent_dentry->d_inode, lower_dentry, mode, nd);
-
-	pathcpy(&nd->path, &saved_path);
+	err = vfs_create(d_inode(lower_parent_dentry), lower_dentry, mode, want_excl);
 	if (err)
 		goto out;
 
@@ -93,11 +84,9 @@ static int sdcardfs_create(struct inode *dir, struct dentry *dentry,
 	if (err)
 		goto out;
 	fsstack_copy_attr_times(dir, sdcardfs_lower_inode(dir));
-	fsstack_copy_inode_size(dir, lower_parent_dentry->d_inode);
+	fsstack_copy_inode_size(dir, d_inode(lower_parent_dentry));
 
 out:
-	mnt_drop_write(lower_path.mnt);
-out_unlock:
 	unlock_dir(lower_parent_dentry);
 	sdcardfs_put_lower_path(dentry, &lower_path);
 	REVERT_CRED(saved_cred);
@@ -118,33 +107,27 @@ static int sdcardfs_link(struct dentry *old_dentry, struct inode *dir,
 
 	OVERRIDE_CRED(SDCARDFS_SB(dir->i_sb));
 
-	file_size_save = i_size_read(old_dentry->d_inode);
+	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 = mnt_want_write(lower_new_path.mnt);
-	if (err)
-		goto out_unlock;
-
-	err = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
-		       lower_new_dentry);
-	if (err || !lower_new_dentry->d_inode)
+	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, lower_new_dentry->d_inode);
-	fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
-	old_dentry->d_inode->i_nlink =
-		  sdcardfs_lower_inode(old_dentry->d_inode)->i_nlink;
-	i_size_write(new_dentry->d_inode, file_size_save);
+	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:
-	mnt_drop_write(lower_new_path.mnt);
-out_unlock:
 	unlock_dir(lower_dir_dentry);
 	sdcardfs_put_lower_path(old_dentry, &lower_old_path);
 	sdcardfs_put_lower_path(new_dentry, &lower_new_path);
@@ -180,10 +163,7 @@ static int sdcardfs_unlink(struct inode *dir, struct dentry *dentry)
 	dget(lower_dentry);
 	lower_dir_dentry = lock_parent(lower_dentry);
 
-	err = mnt_want_write(lower_path.mnt);
-	if (err)
-		goto out_unlock;
-	err = vfs_unlink(lower_dir_inode, lower_dentry);
+	err = vfs_unlink(lower_dir_inode, lower_dentry, NULL);
 
 	/*
 	 * Note: unlinking on top of NFS can cause silly-renamed files.
@@ -198,13 +178,11 @@ static int sdcardfs_unlink(struct inode *dir, struct dentry *dentry)
 		goto out;
 	fsstack_copy_attr_times(dir, lower_dir_inode);
 	fsstack_copy_inode_size(dir, lower_dir_inode);
-	dentry->d_inode->i_nlink =
-		  sdcardfs_lower_inode(dentry->d_inode)->i_nlink;
-	dentry->d_inode->i_ctime = dir->i_ctime;
+	set_nlink(d_inode(dentry),
+		  sdcardfs_lower_inode(d_inode(dentry))->i_nlink);
+	d_inode(dentry)->i_ctime = dir->i_ctime;
 	d_drop(dentry); /* this is needed, else LTP fails (VFS won't do it) */
 out:
-	mnt_drop_write(lower_path.mnt);
-out_unlock:
 	unlock_dir(lower_dir_dentry);
 	dput(lower_dentry);
 	sdcardfs_put_lower_path(dentry, &lower_path);
@@ -217,7 +195,7 @@ out_eacces:
 static int sdcardfs_symlink(struct inode *dir, struct dentry *dentry,
 			  const char *symname)
 {
-	int err = 0;
+	int err;
 	struct dentry *lower_dentry;
 	struct dentry *lower_parent_dentry = NULL;
 	struct path lower_path;
@@ -228,21 +206,16 @@ static int sdcardfs_symlink(struct inode *dir, struct dentry *dentry,
 	lower_dentry = lower_path.dentry;
 	lower_parent_dentry = lock_parent(lower_dentry);
 
-	err = mnt_want_write(lower_path.mnt);
-	if (err)
-		goto out_unlock;
-	err = vfs_symlink(lower_parent_dentry->d_inode, lower_dentry, symname);
+	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, lower_parent_dentry->d_inode);
+	fsstack_copy_inode_size(dir, d_inode(lower_parent_dentry));
 
 out:
-	mnt_drop_write(lower_path.mnt);
-out_unlock:
 	unlock_dir(lower_parent_dentry);
 	sdcardfs_put_lower_path(dentry, &lower_path);
 	REVERT_CRED();
@@ -266,9 +239,9 @@ static int touch(char *abs_path, mode_t mode) {
 	return 0;
 }
 
-static int sdcardfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+static int sdcardfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 {
-	int err = 0;
+	int err;
 	int make_nomedia_in_obb = 0;
 	struct dentry *lower_dentry;
 	struct dentry *lower_parent_dentry = NULL;
@@ -306,13 +279,9 @@ static int sdcardfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 	lower_dentry = lower_path.dentry;
 	lower_parent_dentry = lock_parent(lower_dentry);
 
-	err = mnt_want_write(lower_path.mnt);
-	if (err)
-		goto out_unlock;
-
 	/* set last 16bytes of mode field to 0775 */
 	mode = (mode & S_IFMT) | 00775;
-	err = vfs_mkdir(lower_parent_dentry->d_inode, lower_dentry, mode);
+	err = vfs_mkdir(d_inode(lower_parent_dentry), lower_dentry, mode);
 
 	if (err)
 		goto out;
@@ -341,9 +310,9 @@ static int sdcardfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 		goto out;
 
 	fsstack_copy_attr_times(dir, sdcardfs_lower_inode(dir));
-	fsstack_copy_inode_size(dir, lower_parent_dentry->d_inode);
+	fsstack_copy_inode_size(dir, d_inode(lower_parent_dentry));
 	/* update number of links on parent directory */
-	dir->i_nlink = sdcardfs_lower_inode(dir)->i_nlink;
+	set_nlink(dir, sdcardfs_lower_inode(dir)->i_nlink);
 
 	if ((sbi->options.derive == DERIVE_UNIFIED) && (!strcasecmp(dentry->d_name.name, "obb"))
 		&& (pi->perm == PERM_ANDROID) && (pi->userid == 0))
@@ -388,8 +357,6 @@ static int sdcardfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 		kfree(nomedia_fullpath);
 	}
 out:
-	mnt_drop_write(lower_path.mnt);
-out_unlock:
 	unlock_dir(lower_parent_dentry);
 	sdcardfs_put_lower_path(dentry, &lower_path);
 out_revert:
@@ -427,23 +394,18 @@ static int sdcardfs_rmdir(struct inode *dir, struct dentry *dentry)
 	lower_dentry = lower_path.dentry;
 	lower_dir_dentry = lock_parent(lower_dentry);
 
-	err = mnt_want_write(lower_path.mnt);
-	if (err)
-		goto out_unlock;
-	err = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
+	err = vfs_rmdir(d_inode(lower_dir_dentry), lower_dentry);
 	if (err)
 		goto out;
 
 	d_drop(dentry);	/* drop our dentry on success (why not VFS's job?) */
-	if (dentry->d_inode)
-		clear_nlink(dentry->d_inode);
-	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
-	fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
-	dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
+	if (d_inode(dentry))
+		clear_nlink(d_inode(dentry));
+	fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
+	fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
+	set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
 
 out:
-	mnt_drop_write(lower_path.mnt);
-out_unlock:
 	unlock_dir(lower_dir_dentry);
 	sdcardfs_put_real_lower(dentry, &lower_path);
 	REVERT_CRED(saved_cred);
@@ -452,10 +414,10 @@ out_eacces:
 }
 
 #if 0
-static int sdcardfs_mknod(struct inode *dir, struct dentry *dentry, int mode,
+static int sdcardfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
 			dev_t dev)
 {
-	int err = 0;
+	int err;
 	struct dentry *lower_dentry;
 	struct dentry *lower_parent_dentry = NULL;
 	struct path lower_path;
@@ -466,10 +428,7 @@ static int sdcardfs_mknod(struct inode *dir, struct dentry *dentry, int mode,
 	lower_dentry = lower_path.dentry;
 	lower_parent_dentry = lock_parent(lower_dentry);
 
-	err = mnt_want_write(lower_path.mnt);
-	if (err)
-		goto out_unlock;
-	err = vfs_mknod(lower_parent_dentry->d_inode, lower_dentry, mode, dev);
+	err = vfs_mknod(d_inode(lower_parent_dentry), lower_dentry, mode, dev);
 	if (err)
 		goto out;
 
@@ -477,11 +436,9 @@ static int sdcardfs_mknod(struct inode *dir, struct dentry *dentry, int mode,
 	if (err)
 		goto out;
 	fsstack_copy_attr_times(dir, sdcardfs_lower_inode(dir));
-	fsstack_copy_inode_size(dir, lower_parent_dentry->d_inode);
+	fsstack_copy_inode_size(dir, d_inode(lower_parent_dentry));
 
 out:
-	mnt_drop_write(lower_path.mnt);
-out_unlock:
 	unlock_dir(lower_parent_dentry);
 	sdcardfs_put_lower_path(dentry, &lower_path);
 	REVERT_CRED();
@@ -541,43 +498,33 @@ static int sdcardfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 		goto out;
 	}
 
-	err = mnt_want_write(lower_old_path.mnt);
+	err = vfs_rename(d_inode(lower_old_dir_dentry), lower_old_dentry,
+			 d_inode(lower_new_dir_dentry), lower_new_dentry,
+			 NULL, 0);
 	if (err)
 		goto out;
-	err = mnt_want_write(lower_new_path.mnt);
-	if (err)
-		goto out_drop_old_write;
-
-	err = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
-			 lower_new_dir_dentry->d_inode, lower_new_dentry);
-	if (err)
-		goto out_err;
 
 	/* Copy attrs from lower dir, but i_uid/i_gid */
-	fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
-	fsstack_copy_inode_size(new_dir, lower_new_dir_dentry->d_inode);
+	fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
+	fsstack_copy_inode_size(new_dir, d_inode(lower_new_dir_dentry));
 	fix_derived_permission(new_dir);
 	if (new_dir != old_dir) {
-		fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
-		fsstack_copy_inode_size(old_dir, lower_old_dir_dentry->d_inode);
+		fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
+		fsstack_copy_inode_size(old_dir, d_inode(lower_old_dir_dentry));
 		fix_derived_permission(old_dir);
 		/* update the derived permission of the old_dentry
 		 * with its new parent
 		 */
 		new_parent = dget_parent(new_dentry);
 		if(new_parent) {
-			if(old_dentry->d_inode) {
+			if(d_inode(old_dentry)) {
 				get_derived_permission(new_parent, old_dentry);
-				fix_derived_permission(old_dentry->d_inode);
+				fix_derived_permission(d_inode(old_dentry));
 			}
 			dput(new_parent);
 		}
 	}
 
-out_err:
-	mnt_drop_write(lower_new_path.mnt);
-out_drop_old_write:
-	mnt_drop_write(lower_old_path.mnt);
 out:
 	unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 	dput(lower_old_dir_dentry);
@@ -599,17 +546,17 @@ static int sdcardfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz
 
 	sdcardfs_get_lower_path(dentry, &lower_path);
 	lower_dentry = lower_path.dentry;
-	if (!lower_dentry->d_inode->i_op ||
-	    !lower_dentry->d_inode->i_op->readlink) {
+	if (!d_inode(lower_dentry)->i_op ||
+	    !d_inode(lower_dentry)->i_op->readlink) {
 		err = -EINVAL;
 		goto out;
 	}
 
-	err = lower_dentry->d_inode->i_op->readlink(lower_dentry,
+	err = d_inode(lower_dentry)->i_op->readlink(lower_dentry,
 						    buf, bufsiz);
 	if (err < 0)
 		goto out;
-	fsstack_copy_attr_atime(dentry->d_inode, lower_dentry->d_inode);
+	fsstack_copy_attr_atime(d_inode(dentry), d_inode(lower_dentry));
 
 out:
 	sdcardfs_put_lower_path(dentry, &lower_path);
@@ -618,7 +565,7 @@ out:
 #endif
 
 #if 0
-static void *sdcardfs_follow_link(struct dentry *dentry, struct nameidata *nd)
+static const char *sdcardfs_follow_link(struct dentry *dentry, void **cookie)
 {
 	char *buf;
 	int len = PAGE_SIZE, err;
@@ -628,7 +575,7 @@ static void *sdcardfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 	buf = kmalloc(len, GFP_KERNEL);
 	if (!buf) {
 		buf = ERR_PTR(-ENOMEM);
-		goto out;
+		return buf;
 	}
 
 	/* read the symlink, and then we will follow it */
@@ -642,35 +589,19 @@ static void *sdcardfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 	} else {
 		buf[err] = '\0';
 	}
-out:
-	nd_set_link(nd, buf);
-	return NULL;
-}
-#endif
-
-#if 0
-/* this @nd *IS* still used */
-static void sdcardfs_put_link(struct dentry *dentry, struct nameidata *nd,
-			    void *cookie)
-{
-	char *buf = nd_get_link(nd);
-	if (!IS_ERR(buf))	/* free the char* */
-		kfree(buf);
+	return *cookie = buf;
 }
 #endif
 
-static int sdcardfs_permission(struct inode *inode, int mask, unsigned int flags)
+static int sdcardfs_permission(struct inode *inode, int mask)
 {
 	int err;
 
-	if (flags & IPERM_FLAG_RCU)
-		return -ECHILD;
-
 	/*
 	 * Permission check on sdcardfs inode.
 	 * Calling process should have AID_SDCARD_RW permission
 	 */
-	err = generic_permission(inode, mask, 0, inode->i_op->check_acl);
+	err = generic_permission(inode, mask);
 
 	/* XXX
 	 * Original sdcardfs code calls inode_permission(lower_inode,.. )
@@ -700,49 +631,9 @@ static int sdcardfs_permission(struct inode *inode, int mask, unsigned int flags
 
 }
 
-static int sdcardfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
-		 struct kstat *stat)
-{
-	struct dentry *lower_dentry;
-	struct inode *inode;
-	struct inode *lower_inode;
-	struct path lower_path;
-	struct dentry *parent;
-	struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dentry->d_sb);
-
-	parent = dget_parent(dentry);
-	if(!check_caller_access_to_name(parent->d_inode, dentry->d_name.name,
-						sbi->options.derive, 0, 0)) {
-		printk(KERN_INFO "%s: need to check the caller's gid in packages.list\n"
-						 "  dentry: %s, task:%s\n",
-						 __func__, dentry->d_name.name, current->comm);
-		dput(parent);
-		return -EACCES;
-	}
-	dput(parent);
-
-	inode = dentry->d_inode;
-
-	sdcardfs_get_lower_path(dentry, &lower_path);
-	lower_dentry = lower_path.dentry;
-	lower_inode = sdcardfs_lower_inode(inode);
-
-	fsstack_copy_attr_all(inode, lower_inode);
-	fsstack_copy_inode_size(inode, lower_inode);
-	/* if the dentry has been moved from other location
-	 * so, on this stage, its derived permission must be
-	 * rechecked from its private field.
-	 */
-	fix_derived_permission(inode);
-
-	generic_fillattr(inode, stat);
-	sdcardfs_put_lower_path(dentry, &lower_path);
-	return 0;
-}
-
 static int sdcardfs_setattr(struct dentry *dentry, struct iattr *ia)
 {
-	int err = 0;
+	int err;
 	struct dentry *lower_dentry;
 	struct inode *inode;
 	struct inode *lower_inode;
@@ -752,7 +643,7 @@ static int sdcardfs_setattr(struct dentry *dentry, struct iattr *ia)
 	struct dentry *parent;
 	int has_rw;
 
-	inode = dentry->d_inode;
+	inode = d_inode(dentry);
 
 	/*
 	 * Check if user has permission to change inode.  We don't check if
@@ -766,7 +657,7 @@ static int sdcardfs_setattr(struct dentry *dentry, struct iattr *ia)
 		/* check the Android group ID */
 		has_rw = get_caller_has_rw_locked(sbi->pkgl_id, sbi->options.derive);
 		parent = dget_parent(dentry);
-		if(!check_caller_access_to_name(parent->d_inode, dentry->d_name.name,
+		if(!check_caller_access_to_name(d_inode(parent), dentry->d_name.name,
 						sbi->options.derive, 1, has_rw)) {
 			printk(KERN_INFO "%s: need to check the caller's gid in packages.list\n"
 							 "  dentry: %s, task:%s\n",
@@ -819,13 +710,14 @@ static int sdcardfs_setattr(struct dentry *dentry, struct iattr *ia)
 
 	/* notify the (possibly copied-up) lower inode */
 	/*
-	 * Note: we use lower_dentry->d_inode, because lower_inode may be
+	 * Note: we use d_inode(lower_dentry), because lower_inode may be
 	 * unlinked (no inode->i_sb and i_ino==0.  This happens if someone
 	 * tries to open(), unlink(), then ftruncate() a file.
 	 */
-	mutex_lock(&lower_dentry->d_inode->i_mutex);
-	err = notify_change(lower_dentry, &lower_ia); /* note: lower_ia */
-	mutex_unlock(&lower_dentry->d_inode->i_mutex);
+	mutex_lock(&d_inode(lower_dentry)->i_mutex);
+	err = notify_change(lower_dentry, &lower_ia, /* note: lower_ia */
+			NULL);
+	mutex_unlock(&d_inode(lower_dentry)->i_mutex);
 	if (current->mm)
 		up_write(&current->mm->mmap_sem);
 	if (err)
@@ -848,6 +740,46 @@ out_err:
 	return err;
 }
 
+static int sdcardfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
+		 struct kstat *stat)
+{
+	struct dentry *lower_dentry;
+	struct inode *inode;
+	struct inode *lower_inode;
+	struct path lower_path;
+	struct dentry *parent;
+	struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dentry->d_sb);
+
+	parent = dget_parent(dentry);
+	if(!check_caller_access_to_name(d_inode(parent), dentry->d_name.name,
+						sbi->options.derive, 0, 0)) {
+		printk(KERN_INFO "%s: need to check the caller's gid in packages.list\n"
+						 "  dentry: %s, task:%s\n",
+						 __func__, dentry->d_name.name, current->comm);
+		dput(parent);
+		return -EACCES;
+	}
+	dput(parent);
+
+	inode = d_inode(dentry);
+
+	sdcardfs_get_lower_path(dentry, &lower_path);
+	lower_dentry = lower_path.dentry;
+	lower_inode = sdcardfs_lower_inode(inode);
+
+	fsstack_copy_attr_all(inode, lower_inode);
+	fsstack_copy_inode_size(inode, lower_inode);
+	/* if the dentry has been moved from other location
+	 * so, on this stage, its derived permission must be
+	 * rechecked from its private field.
+	 */
+	fix_derived_permission(inode);
+
+	generic_fillattr(inode, stat);
+	sdcardfs_put_lower_path(dentry, &lower_path);
+	return 0;
+}
+
 const struct inode_operations sdcardfs_symlink_iops = {
 	.permission	= sdcardfs_permission,
 	.setattr	= sdcardfs_setattr,
@@ -856,14 +788,16 @@ const struct inode_operations sdcardfs_symlink_iops = {
 	 *     These methods are *NOT* perfectly tested.
 	.readlink	= sdcardfs_readlink,
 	.follow_link	= sdcardfs_follow_link,
-	.put_link	= sdcardfs_put_link,
+	.put_link	= kfree_put_link,
 	 */
 };
 
 const struct inode_operations sdcardfs_dir_iops = {
 	.create		= sdcardfs_create,
 	.lookup		= sdcardfs_lookup,
+#if 0
 	.permission	= sdcardfs_permission,
+#endif
 	.unlink		= sdcardfs_unlink,
 	.mkdir		= sdcardfs_mkdir,
 	.rmdir		= sdcardfs_rmdir,
diff --git a/fs/sdcardfs/lookup.c b/fs/sdcardfs/lookup.c
index c0b12375b1bf..a4b94df99f32 100644
--- a/fs/sdcardfs/lookup.c
+++ b/fs/sdcardfs/lookup.c
@@ -79,8 +79,7 @@ static int sdcardfs_inode_set(struct inode *inode, void *lower_inode)
 	return 0;
 }
 
-static struct inode *sdcardfs_iget(struct super_block *sb,
-				 struct inode *lower_inode)
+struct inode *sdcardfs_iget(struct super_block *sb, struct inode *lower_inode)
 {
 	struct sdcardfs_inode_info *info;
 	struct inode *inode; /* the new inode to return */
@@ -206,14 +205,13 @@ out:
  * Fills in lower_parent_path with <dentry,mnt> on success.
  */
 static struct dentry *__sdcardfs_lookup(struct dentry *dentry,
-		struct nameidata *nd, struct path *lower_parent_path)
+		unsigned int flags, struct path *lower_parent_path)
 {
 	int err = 0;
 	struct vfsmount *lower_dir_mnt;
 	struct dentry *lower_dir_dentry = NULL;
 	struct dentry *lower_dentry;
 	const char *name;
-	struct nameidata lower_nd;
 	struct path lower_path;
 	struct qstr this;
 	struct sdcardfs_sb_info *sbi;
@@ -234,10 +232,10 @@ static struct dentry *__sdcardfs_lookup(struct dentry *dentry,
 	/* Use vfs_path_lookup to check if the dentry exists or not */
 	if (sbi->options.lower_fs == LOWER_FS_EXT4) {
 		err = vfs_path_lookup(lower_dir_dentry, lower_dir_mnt, name,
-				LOOKUP_CASE_INSENSITIVE, &lower_nd);
+				LOOKUP_CASE_INSENSITIVE, &lower_path);
 	} else if (sbi->options.lower_fs == LOWER_FS_FAT) {
 		err = vfs_path_lookup(lower_dir_dentry, lower_dir_mnt, name, 0,
-				&lower_nd);
+				&lower_path);
 	}
 
 	/* no error: handle positive dentries */
@@ -253,7 +251,7 @@ static struct dentry *__sdcardfs_lookup(struct dentry *dentry,
 			 * and the base obbpath will be copyed to the lower_path variable.
 			 * if an error returned, there's no change in the lower_path
 			 * 		returns: -ERRNO if error (0: no error) */
-			err = setup_obb_dentry(dentry, &lower_nd.path);
+			err = setup_obb_dentry(dentry, &lower_path);
 
 			if(err) {
 				/* if the sbi->obbpath is not available, we can optionally
@@ -267,8 +265,8 @@ static struct dentry *__sdcardfs_lookup(struct dentry *dentry,
 			}
 		}
 
-		sdcardfs_set_lower_path(dentry, &lower_nd.path);
-		err = sdcardfs_interpose(dentry, dentry->d_sb, &lower_nd.path);
+		sdcardfs_set_lower_path(dentry, &lower_path);
+		err = sdcardfs_interpose(dentry, dentry->d_sb, &lower_path);
 		if (err) /* path_put underlying path on error */
 			sdcardfs_put_reset_lower_path(dentry);
 		goto out;
@@ -306,10 +304,7 @@ setup_lower:
 	 * the VFS will continue the process of making this negative dentry
 	 * into a positive one.
 	 */
-	if (nd) {
-		if (nd->flags & (LOOKUP_CREATE|LOOKUP_RENAME_TARGET))
-			err = 0;
-	} else
+	if (flags & (LOOKUP_CREATE|LOOKUP_RENAME_TARGET))
 		err = 0;
 
 out:
@@ -328,7 +323,7 @@ out:
  * @nd : nameidata of parent inode
  */
 struct dentry *sdcardfs_lookup(struct inode *dir, struct dentry *dentry,
-			     struct nameidata *nd)
+			     unsigned int flags)
 {
 	struct dentry *ret = NULL, *parent;
 	struct path lower_parent_path;
@@ -359,7 +354,7 @@ struct dentry *sdcardfs_lookup(struct inode *dir, struct dentry *dentry,
 		goto out;
 	}
 
-	ret = __sdcardfs_lookup(dentry, nd, &lower_parent_path);
+	ret = __sdcardfs_lookup(dentry, flags, &lower_parent_path);
 	if (IS_ERR(ret))
 	{
 		goto out;
diff --git a/fs/sdcardfs/main.c b/fs/sdcardfs/main.c
index 1fdceffec72c..9d04ae8ceb46 100644
--- a/fs/sdcardfs/main.c
+++ b/fs/sdcardfs/main.c
@@ -156,6 +156,7 @@ invalid_option:
 	return 0;
 }
 
+#if 0
 /*
  * our custom d_alloc_root work-alike
  *
@@ -181,6 +182,7 @@ static struct dentry *sdcardfs_d_alloc_root(struct super_block *sb)
 	}
 	return ret;
 }
+#endif
 
 /*
  * There is no need to lock the sdcardfs_super_info's rwsem as there is no
@@ -195,6 +197,7 @@ static int sdcardfs_read_super(struct super_block *sb, const char *dev_name,
 	struct path lower_path;
 	struct sdcardfs_sb_info *sb_info;
 	void *pkgl_id;
+	struct inode *inode;
 
 	printk(KERN_INFO "sdcardfs version 2.0\n");
 
@@ -259,12 +262,18 @@ static int sdcardfs_read_super(struct super_block *sb, const char *dev_name,
 	sb->s_magic = SDCARDFS_SUPER_MAGIC;
 	sb->s_op = &sdcardfs_sops;
 
-	/* see comment next to the definition of sdcardfs_d_alloc_root */
-	sb->s_root = sdcardfs_d_alloc_root(sb);
+	/* get a new inode and allocate our root dentry */
+	inode = sdcardfs_iget(sb, lower_path.dentry->d_inode);
+	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_sput;
+		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;
@@ -275,56 +284,60 @@ static int sdcardfs_read_super(struct super_block *sb, const char *dev_name,
 	/* set the lower dentries for s_root */
 	sdcardfs_set_lower_path(sb->s_root, &lower_path);
 
-	/* call interpose to create the upper level inode */
-	err = sdcardfs_interpose(sb->s_root, sb, &lower_path);
-	if (!err) {
-		/* setup permission policy */
-		switch(sb_info->options.derive) {
-			case DERIVE_NONE:
-				setup_derived_state(sb->s_root->d_inode,
-					PERM_ROOT, 0, AID_ROOT, AID_SDCARD_RW, 00775);
-				sb_info->obbpath_s = NULL;
-				break;
-			case DERIVE_LEGACY:
-				/* Legacy behavior used to support internal multiuser layout which
-				 * places user_id at the top directory level, with the actual roots
-				 * just below that. Shared OBB path is also at top level. */
-				setup_derived_state(sb->s_root->d_inode,
-				        PERM_LEGACY_PRE_ROOT, 0, AID_ROOT, AID_SDCARD_R, 00771);
-				/* initialize the obbpath string and lookup the path
-				 * sb_info->obb_path will be deactivated by path_put
-				 * on sdcardfs_put_super */
-				sb_info->obbpath_s = kzalloc(PATH_MAX, GFP_KERNEL);
-				snprintf(sb_info->obbpath_s, PATH_MAX, "%s/obb", dev_name);
-				err =  prepare_dir(sb_info->obbpath_s,
-							sb_info->options.fs_low_uid,
-							sb_info->options.fs_low_gid, 00755);
-				if(err)
-					printk(KERN_ERR "sdcardfs: %s: %d, error on creating %s\n",
-							__func__,__LINE__, sb_info->obbpath_s);
-				break;
-			case DERIVE_UNIFIED:
-				/* Unified multiuser layout which places secondary user_id under
-				 * /Android/user and shared OBB path under /Android/obb. */
-				setup_derived_state(sb->s_root->d_inode,
-						PERM_ROOT, 0, AID_ROOT, AID_SDCARD_R, 00771);
-
-				sb_info->obbpath_s = kzalloc(PATH_MAX, GFP_KERNEL);
-				snprintf(sb_info->obbpath_s, PATH_MAX, "%s/Android/obb", dev_name);
-				break;
-		}
-		fix_derived_permission(sb->s_root->d_inode);
+	/*
+	 * 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);
 
-		if (!silent)
-			printk(KERN_INFO "sdcardfs: mounted on top of %s type %s\n",
-						dev_name, lower_sb->s_type->name);
-		goto out;
+	/* setup permission policy */
+	switch(sb_info->options.derive) {
+		case DERIVE_NONE:
+			setup_derived_state(sb->s_root->d_inode,
+					PERM_ROOT, 0, AID_ROOT, AID_SDCARD_RW, 00775);
+			sb_info->obbpath_s = NULL;
+			break;
+		case DERIVE_LEGACY:
+			/* Legacy behavior used to support internal multiuser layout which
+			 * places user_id at the top directory level, with the actual roots
+			 * just below that. Shared OBB path is also at top level. */
+			setup_derived_state(sb->s_root->d_inode,
+					PERM_LEGACY_PRE_ROOT, 0, AID_ROOT, AID_SDCARD_R, 00771);
+			/* initialize the obbpath string and lookup the path
+			 * sb_info->obb_path will be deactivated by path_put
+			 * on sdcardfs_put_super */
+			sb_info->obbpath_s = kzalloc(PATH_MAX, GFP_KERNEL);
+			snprintf(sb_info->obbpath_s, PATH_MAX, "%s/obb", dev_name);
+			err =  prepare_dir(sb_info->obbpath_s,
+					sb_info->options.fs_low_uid,
+					sb_info->options.fs_low_gid, 00755);
+			if(err)
+				printk(KERN_ERR "sdcardfs: %s: %d, error on creating %s\n",
+						__func__,__LINE__, sb_info->obbpath_s);
+			break;
+		case DERIVE_UNIFIED:
+			/* Unified multiuser layout which places secondary user_id under
+			 * /Android/user and shared OBB path under /Android/obb. */
+			setup_derived_state(sb->s_root->d_inode,
+					PERM_ROOT, 0, AID_ROOT, AID_SDCARD_R, 00771);
+
+			sb_info->obbpath_s = kzalloc(PATH_MAX, GFP_KERNEL);
+			snprintf(sb_info->obbpath_s, PATH_MAX, "%s/Android/obb", dev_name);
+			break;
 	}
-	/* else error: fall through */
+	fix_derived_permission(sb->s_root->d_inode);
+
+	if (!silent)
+		printk(KERN_INFO "sdcardfs: mounted on top of %s type %s\n",
+				dev_name, lower_sb->s_type->name);
+	goto out; /* all is well */
 
-	free_dentry_private_data(sb->s_root);
+	/* 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);
@@ -346,7 +359,7 @@ static struct dentry *mount_nodev_with_options(struct file_system_type *fs_type,
 
 {
 	int error;
-	struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL);
+	struct super_block *s = sget(fs_type, NULL, set_anon_super, flags, NULL);
 
 	if (IS_ERR(s))
 		return ERR_CAST(s);
@@ -378,7 +391,7 @@ static struct file_system_type sdcardfs_fs_type = {
 	.name		= SDCARDFS_NAME,
 	.mount		= sdcardfs_mount,
 	.kill_sb	= generic_shutdown_super,
-	.fs_flags	= FS_REVAL_DOT,
+	.fs_flags	= 0,
 };
 
 static int __init init_sdcardfs_fs(void)
diff --git a/fs/sdcardfs/mmap.c b/fs/sdcardfs/mmap.c
index c807d7f18f8b..e21f64675a80 100644
--- a/fs/sdcardfs/mmap.c
+++ b/fs/sdcardfs/mmap.c
@@ -48,9 +48,8 @@ static int sdcardfs_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 	return err;
 }
 
-static ssize_t sdcardfs_direct_IO(int rw, struct kiocb *iocb,
-			      const struct iovec *iov, loff_t offset,
-			      unsigned long nr_segs)
+static ssize_t sdcardfs_direct_IO(struct kiocb *iocb,
+		struct iov_iter *iter, loff_t pos)
 {
 	/*
      * This function returns zero on purpose in order to support direct IO.
diff --git a/fs/sdcardfs/packagelist.c b/fs/sdcardfs/packagelist.c
index c786d8f92203..d7ba8d4a423e 100644
--- a/fs/sdcardfs/packagelist.c
+++ b/fs/sdcardfs/packagelist.c
@@ -20,7 +20,7 @@
 
 #include "sdcardfs.h"
 #include "strtok.h"
-#include "hashtable.h"
+#include <linux/hashtable.h>
 #include <linux/syscalls.h>
 #include <linux/kthread.h>
 #include <linux/inotify.h>
@@ -29,8 +29,8 @@
 #define STRING_BUF_SIZE		(512)
 
 struct hashtable_entry {
-        struct hlist_node hlist;
-        void *key;
+	struct hlist_node hlist;
+	void *key;
 	int value;
 };
 
@@ -67,12 +67,12 @@ static unsigned int str_hash(void *key) {
 }
 
 static int contain_appid_key(struct packagelist_data *pkgl_dat, void *appid) {
-        struct hashtable_entry *hash_cur;
-	struct hlist_node *h_n;
+	struct hashtable_entry *hash_cur;
+
+	hash_for_each_possible(pkgl_dat->appid_with_rw, hash_cur, hlist, (unsigned int)appid)
 
-        hash_for_each_possible(pkgl_dat->appid_with_rw,	hash_cur, hlist, (unsigned int)appid, h_n)
-                if (appid == hash_cur->key)
-                        return 1;
+		if (appid == hash_cur->key)
+			return 1;
 	return 0;
 }
 
@@ -87,7 +87,7 @@ int get_caller_has_rw_locked(void *pkgl_id, derive_t derive) {
 		return 1;
 	}
 
-	appid = multiuser_get_app_id(current_fsuid());
+	appid = multiuser_get_app_id(from_kuid(&init_user_ns, current_fsuid()));
 	mutex_lock(&pkgl_dat->hashtable_lock);
 	ret = contain_appid_key(pkgl_dat, (void *)appid);
 	mutex_unlock(&pkgl_dat->hashtable_lock);
@@ -98,13 +98,12 @@ appid_t get_appid(void *pkgl_id, const char *app_name)
 {
 	struct packagelist_data *pkgl_dat = (struct packagelist_data *)pkgl_id;
 	struct hashtable_entry *hash_cur;
-	struct hlist_node *h_n;
 	unsigned int hash = str_hash((void *)app_name);
 	appid_t ret_id;
 
 	//printk(KERN_INFO "sdcardfs: %s: %s, %u\n", __func__, (char *)app_name, hash);
 	mutex_lock(&pkgl_dat->hashtable_lock);
-	hash_for_each_possible(pkgl_dat->package_to_appid, hash_cur, hlist, hash, h_n) {
+	hash_for_each_possible(pkgl_dat->package_to_appid, hash_cur, hlist, hash) {
 		//printk(KERN_INFO "sdcardfs: %s: %s\n", __func__, (char *)hash_cur->key);
 		if (!strcasecmp(app_name, hash_cur->key)) {
 			ret_id = (appid_t)hash_cur->value;
@@ -140,7 +139,7 @@ int check_caller_access_to_name(struct inode *parent_node, const char* name,
 
 	/* Root always has access; access for any other UIDs should always
 	 * be controlled through packages.list. */
-	if (current_fsuid() == 0) {
+	if (from_kuid(&init_user_ns, current_fsuid()) == 0) {
 		return 1;
 	}
 
@@ -148,7 +147,8 @@ int check_caller_access_to_name(struct inode *parent_node, const char* name,
 	 * parent or holds sdcard_rw. */
 	if (w_ok) {
 		if (parent_node &&
-			(current_fsuid() == SDCARDFS_I(parent_node)->d_uid)) {
+			(from_kuid(&init_user_ns, current_fsuid()) ==
+			 SDCARDFS_I(parent_node)->d_uid)) {
 			return 1;
 		}
 		return has_rw;
@@ -174,11 +174,10 @@ int open_flags_to_access_mode(int open_flags) {
 static int insert_str_to_int(struct packagelist_data *pkgl_dat, void *key, int value) {
 	struct hashtable_entry *hash_cur;
 	struct hashtable_entry *new_entry;
-	struct hlist_node *h_n;
 	unsigned int hash = str_hash(key);
 
 	//printk(KERN_INFO "sdcardfs: %s: %s: %d, %u\n", __func__, (char *)key, value, hash);
-	hash_for_each_possible(pkgl_dat->package_to_appid, hash_cur, hlist, hash, h_n) {
+	hash_for_each_possible(pkgl_dat->package_to_appid, hash_cur, hlist, hash) {
 		if (!strcasecmp(key, hash_cur->key)) {
 			hash_cur->value = value;
 			return 0;
@@ -202,11 +201,10 @@ static void remove_str_to_int(struct hashtable_entry *h_entry) {
 static int insert_int_to_null(struct packagelist_data *pkgl_dat, void *key, int value) {
 	struct hashtable_entry *hash_cur;
 	struct hashtable_entry *new_entry;
-	struct hlist_node *h_n;
 
 	//printk(KERN_INFO "sdcardfs: %s: %d: %d\n", __func__, (int)key, value);
 	hash_for_each_possible(pkgl_dat->appid_with_rw,	hash_cur, hlist,
-					(unsigned int)key, h_n) {
+					(unsigned int)key) {
 		if (key == hash_cur->key) {
 			hash_cur->value = value;
 			return 0;
@@ -230,14 +228,13 @@ static void remove_int_to_null(struct hashtable_entry *h_entry) {
 static void remove_all_hashentrys(struct packagelist_data *pkgl_dat)
 {
 	struct hashtable_entry *hash_cur;
-	struct hlist_node *h_n;
 	struct hlist_node *h_t;
 	int i;
 
-	hash_for_each_safe(pkgl_dat->package_to_appid, i, h_t, hash_cur, hlist, h_n)
+	hash_for_each_safe(pkgl_dat->package_to_appid, i, h_t, hash_cur, hlist)
 		remove_str_to_int(hash_cur);
-	hash_for_each_safe(pkgl_dat->appid_with_rw, i, h_t, hash_cur, hlist, h_n)
-                remove_int_to_null(hash_cur);
+	hash_for_each_safe(pkgl_dat->appid_with_rw, i, h_t, hash_cur, hlist)
+		remove_int_to_null(hash_cur);
 
 	hash_init(pkgl_dat->package_to_appid);
 	hash_init(pkgl_dat->appid_with_rw);
diff --git a/fs/sdcardfs/sdcardfs.h b/fs/sdcardfs/sdcardfs.h
index 90f8b24e4a52..51f6c7912584 100644
--- a/fs/sdcardfs/sdcardfs.h
+++ b/fs/sdcardfs/sdcardfs.h
@@ -69,8 +69,8 @@
 
 #define fix_derived_permission(x)	\
 	do {						\
-		(x)->i_uid = SDCARDFS_I(x)->d_uid;	\
-		(x)->i_gid = SDCARDFS_I(x)->d_gid;	\
+		(x)->i_uid = make_kuid(&init_user_ns, SDCARDFS_I(x)->d_uid);	\
+		(x)->i_gid = make_kgid(&init_user_ns, SDCARDFS_I(x)->d_gid);	\
 		(x)->i_mode = ((x)->i_mode & S_IFMT) | SDCARDFS_I(x)->d_mode;\
 	} while (0)
 
@@ -159,7 +159,9 @@ extern void sdcardfs_destroy_dentry_cache(void);
 extern int new_dentry_private_data(struct dentry *dentry);
 extern void free_dentry_private_data(struct dentry *dentry);
 extern struct dentry *sdcardfs_lookup(struct inode *dir, struct dentry *dentry,
-				    struct nameidata *nd);
+				unsigned int flags);
+extern struct inode *sdcardfs_iget(struct super_block *sb,
+				 struct inode *lower_inode);
 extern int sdcardfs_interpose(struct dentry *dentry, struct super_block *sb,
 			    struct path *lower_path);
 
@@ -387,13 +389,13 @@ extern int setup_obb_dentry(struct dentry *dentry, struct path *lower_path);
 static inline struct dentry *lock_parent(struct dentry *dentry)
 {
 	struct dentry *dir = dget_parent(dentry);
-	mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
+	mutex_lock_nested(&d_inode(dir)->i_mutex, I_MUTEX_PARENT);
 	return dir;
 }
 
 static inline void unlock_dir(struct dentry *dir)
 {
-	mutex_unlock(&dir->d_inode->i_mutex);
+	mutex_unlock(&d_inode(dir)->i_mutex);
 	dput(dir);
 }
 
@@ -402,16 +404,9 @@ static inline int prepare_dir(const char *path_s, uid_t uid, gid_t gid, mode_t m
 	int err;
 	struct dentry *dent;
 	struct iattr attrs;
-	struct nameidata nd;
+	struct path parent;
 
-	err = kern_path_parent(path_s, &nd);
-	if (err) {
-		if (err == -EEXIST)
-			err = 0;
-		goto out;
-	}
-
-	dent = lookup_create(&nd, 1);
+	dent = kern_path_locked(path_s, &parent);
 	if (IS_ERR(dent)) {
 		err = PTR_ERR(dent);
 		if (err == -EEXIST)
@@ -419,29 +414,27 @@ static inline int prepare_dir(const char *path_s, uid_t uid, gid_t gid, mode_t m
 		goto out_unlock;
 	}
 
-	err = vfs_mkdir(nd.path.dentry->d_inode, dent, mode);
+	err = vfs_mkdir(d_inode(parent.dentry), dent, mode);
 	if (err) {
 		if (err == -EEXIST)
 			err = 0;
 		goto out_dput;
 	}
 
-	attrs.ia_uid = uid;
-	attrs.ia_gid = gid;
+	attrs.ia_uid = make_kuid(&init_user_ns, uid);
+	attrs.ia_gid = make_kgid(&init_user_ns, gid);
 	attrs.ia_valid = ATTR_UID | ATTR_GID;
-	mutex_lock(&dent->d_inode->i_mutex);
-	notify_change(dent, &attrs);
-	mutex_unlock(&dent->d_inode->i_mutex);
+	mutex_lock(&d_inode(dent)->i_mutex);
+	notify_change(dent, &attrs, NULL);
+	mutex_unlock(&d_inode(dent)->i_mutex);
 
 out_dput:
 	dput(dent);
 
 out_unlock:
 	/* parent dentry locked by lookup_create */
-	mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
-	path_put(&nd.path);
-
-out:
+	mutex_unlock(&d_inode(parent.dentry)->i_mutex);
+	path_put(&parent);
 	return err;
 }
 
diff --git a/fs/sdcardfs/super.c b/fs/sdcardfs/super.c
index 1d206c82dfdf..f153ce1b8cf3 100644
--- a/fs/sdcardfs/super.c
+++ b/fs/sdcardfs/super.c
@@ -122,7 +122,7 @@ static void sdcardfs_evict_inode(struct inode *inode)
 	struct inode *lower_inode;
 
 	truncate_inode_pages(&inode->i_data, 0);
-	end_writeback(inode);
+	clear_inode(inode);
 	/*
 	 * Decrement a reference to a lower_inode, which was incremented
 	 * by our read_inode when it was created initially.
@@ -193,9 +193,9 @@ static void sdcardfs_umount_begin(struct super_block *sb)
 		lower_sb->s_op->umount_begin(lower_sb);
 }
 
-static int sdcardfs_show_options(struct seq_file *m, struct vfsmount *mnt)
+static int sdcardfs_show_options(struct seq_file *m, struct dentry *root)
 {
-	struct sdcardfs_sb_info *sbi = SDCARDFS_SB(mnt->mnt_sb);
+	struct sdcardfs_sb_info *sbi = SDCARDFS_SB(root->d_sb);
 	struct sdcardfs_mount_options *opts = &sbi->options;
 
 	if (opts->fs_low_uid != 0)
diff --git a/include/linux/namei.h b/include/linux/namei.h
index e95212f693d6..8b6b620aecc2 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -79,6 +79,8 @@ extern struct dentry *user_path_create(int, const char __user *, struct path *,
 extern void done_path_create(struct path *, struct dentry *);
 extern struct dentry *kern_path_locked(const char *, struct path *);
 extern int kern_path_mountpoint(int, const char *, struct path *, unsigned int);
+extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
+		const char *, unsigned int, struct path *);
 
 extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
 extern struct dentry *lookup_one_len_unlocked(const char *, struct dentry *, int);