1 files changed, 61 insertions, 901 deletions

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 4948d9bc405..0b45ff42f37 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -13,736 +13,55 @@
 #undef DEBUG
 
 #include <linux/fs.h>
-#include <linux/mount.h>
-#include <linux/module.h>
 #include <linux/kobject.h>
-#include <linux/namei.h>
-#include <linux/idr.h>
-#include <linux/completion.h>
-#include <linux/mutex.h>
+#include <linux/slab.h>
 #include "sysfs.h"
 
-DEFINE_MUTEX(sysfs_mutex);
-DEFINE_MUTEX(sysfs_rename_mutex);
-DEFINE_SPINLOCK(sysfs_assoc_lock);
+DEFINE_SPINLOCK(sysfs_symlink_target_lock);
 
-static DEFINE_SPINLOCK(sysfs_ino_lock);
-static DEFINE_IDA(sysfs_ino_ida);
-
-/**
- *	sysfs_link_sibling - link sysfs_dirent into sibling list
- *	@sd: sysfs_dirent of interest
- *
- *	Link @sd into its sibling list which starts from
- *	sd->s_parent->s_dir.children.
- *
- *	Locking:
- *	mutex_lock(sysfs_mutex)
- */
-static void sysfs_link_sibling(struct sysfs_dirent *sd)
-{
-	struct sysfs_dirent *parent_sd = sd->s_parent;
-	struct sysfs_dirent **pos;
-
-	BUG_ON(sd->s_sibling);
-
-	/* Store directory entries in order by ino.  This allows
-	 * readdir to properly restart without having to add a
-	 * cursor into the s_dir.children list.
-	 */
-	for (pos = &parent_sd->s_dir.children; *pos; pos = &(*pos)->s_sibling) {
-		if (sd->s_ino < (*pos)->s_ino)
-			break;
-	}
-	sd->s_sibling = *pos;
-	*pos = sd;
-}
-
-/**
- *	sysfs_unlink_sibling - unlink sysfs_dirent from sibling list
- *	@sd: sysfs_dirent of interest
- *
- *	Unlink @sd from its sibling list which starts from
- *	sd->s_parent->s_dir.children.
- *
- *	Locking:
- *	mutex_lock(sysfs_mutex)
- */
-static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
-{
-	struct sysfs_dirent **pos;
-
-	for (pos = &sd->s_parent->s_dir.children; *pos;
-	     pos = &(*pos)->s_sibling) {
-		if (*pos == sd) {
-			*pos = sd->s_sibling;
-			sd->s_sibling = NULL;
-			break;
-		}
-	}
-}
-
-/**
- *	sysfs_get_dentry - get dentry for the given sysfs_dirent
- *	@sd: sysfs_dirent of interest
- *
- *	Get dentry for @sd.  Dentry is looked up if currently not
- *	present.  This function descends from the root looking up
- *	dentry for each step.
- *
- *	LOCKING:
- *	mutex_lock(sysfs_rename_mutex)
- *
- *	RETURNS:
- *	Pointer to found dentry on success, ERR_PTR() value on error.
- */
-struct dentry *sysfs_get_dentry(struct sysfs_dirent *sd)
-{
-	struct dentry *dentry = dget(sysfs_sb->s_root);
-
-	while (dentry->d_fsdata != sd) {
-		struct sysfs_dirent *cur;
-		struct dentry *parent;
-
-		/* find the first ancestor which hasn't been looked up */
-		cur = sd;
-		while (cur->s_parent != dentry->d_fsdata)
-			cur = cur->s_parent;
-
-		/* look it up */
-		parent = dentry;
-		mutex_lock(&parent->d_inode->i_mutex);
-		dentry = lookup_one_noperm(cur->s_name, parent);
-		mutex_unlock(&parent->d_inode->i_mutex);
-		dput(parent);
-
-		if (IS_ERR(dentry))
-			break;
-	}
-	return dentry;
-}
-
-/**
- *	sysfs_get_active - get an active reference to sysfs_dirent
- *	@sd: sysfs_dirent to get an active reference to
- *
- *	Get an active reference of @sd.  This function is noop if @sd
- *	is NULL.
- *
- *	RETURNS:
- *	Pointer to @sd on success, NULL on failure.
- */
-static struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
-{
-	if (unlikely(!sd))
-		return NULL;
-
-	while (1) {
-		int v, t;
-
-		v = atomic_read(&sd->s_active);
-		if (unlikely(v < 0))
-			return NULL;
-
-		t = atomic_cmpxchg(&sd->s_active, v, v + 1);
-		if (likely(t == v))
-			return sd;
-		if (t < 0)
-			return NULL;
-
-		cpu_relax();
-	}
-}
-
-/**
- *	sysfs_put_active - put an active reference to sysfs_dirent
- *	@sd: sysfs_dirent to put an active reference to
- *
- *	Put an active reference to @sd.  This function is noop if @sd
- *	is NULL.
- */
-static void sysfs_put_active(struct sysfs_dirent *sd)
-{
-	struct completion *cmpl;
-	int v;
-
-	if (unlikely(!sd))
-		return;
-
-	v = atomic_dec_return(&sd->s_active);
-	if (likely(v != SD_DEACTIVATED_BIAS))
-		return;
-
-	/* atomic_dec_return() is a mb(), we'll always see the updated
-	 * sd->s_sibling.
-	 */
-	cmpl = (void *)sd->s_sibling;
-	complete(cmpl);
-}
-
-/**
- *	sysfs_get_active_two - get active references to sysfs_dirent and parent
- *	@sd: sysfs_dirent of interest
- *
- *	Get active reference to @sd and its parent.  Parent's active
- *	reference is grabbed first.  This function is noop if @sd is
- *	NULL.
- *
- *	RETURNS:
- *	Pointer to @sd on success, NULL on failure.
- */
-struct sysfs_dirent *sysfs_get_active_two(struct sysfs_dirent *sd)
-{
-	if (sd) {
-		if (sd->s_parent && unlikely(!sysfs_get_active(sd->s_parent)))
-			return NULL;
-		if (unlikely(!sysfs_get_active(sd))) {
-			sysfs_put_active(sd->s_parent);
-			return NULL;
-		}
-	}
-	return sd;
-}
-
-/**
- *	sysfs_put_active_two - put active references to sysfs_dirent and parent
- *	@sd: sysfs_dirent of interest
- *
- *	Put active references to @sd and its parent.  This function is
- *	noop if @sd is NULL.
- */
-void sysfs_put_active_two(struct sysfs_dirent *sd)
-{
-	if (sd) {
-		sysfs_put_active(sd);
-		sysfs_put_active(sd->s_parent);
-	}
-}
-
-/**
- *	sysfs_deactivate - deactivate sysfs_dirent
- *	@sd: sysfs_dirent to deactivate
- *
- *	Deny new active references and drain existing ones.
- */
-static void sysfs_deactivate(struct sysfs_dirent *sd)
-{
-	DECLARE_COMPLETION_ONSTACK(wait);
-	int v;
-
-	BUG_ON(sd->s_sibling || !(sd->s_flags & SYSFS_FLAG_REMOVED));
-	sd->s_sibling = (void *)&wait;
-
-	/* atomic_add_return() is a mb(), put_active() will always see
-	 * the updated sd->s_sibling.
-	 */
-	v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active);
-
-	if (v != SD_DEACTIVATED_BIAS)
-		wait_for_completion(&wait);
-
-	sd->s_sibling = NULL;
-}
-
-static int sysfs_alloc_ino(ino_t *pino)
-{
-	int ino, rc;
-
- retry:
-	spin_lock(&sysfs_ino_lock);
-	rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino);
-	spin_unlock(&sysfs_ino_lock);
-
-	if (rc == -EAGAIN) {
-		if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL))
-			goto retry;
-		rc = -ENOMEM;
-	}
-
-	*pino = ino;
-	return rc;
-}
-
-static void sysfs_free_ino(ino_t ino)
-{
-	spin_lock(&sysfs_ino_lock);
-	ida_remove(&sysfs_ino_ida, ino);
-	spin_unlock(&sysfs_ino_lock);
-}
-
-void release_sysfs_dirent(struct sysfs_dirent * sd)
-{
-	struct sysfs_dirent *parent_sd;
-
- repeat:
-	/* Moving/renaming is always done while holding reference.
-	 * sd->s_parent won't change beneath us.
-	 */
-	parent_sd = sd->s_parent;
-
-	if (sysfs_type(sd) == SYSFS_KOBJ_LINK)
-		sysfs_put(sd->s_symlink.target_sd);
-	if (sysfs_type(sd) & SYSFS_COPY_NAME)
-		kfree(sd->s_name);
-	kfree(sd->s_iattr);
-	sysfs_free_ino(sd->s_ino);
-	kmem_cache_free(sysfs_dir_cachep, sd);
-
-	sd = parent_sd;
-	if (sd && atomic_dec_and_test(&sd->s_count))
-		goto repeat;
-}
-
-static void sysfs_d_iput(struct dentry * dentry, struct inode * inode)
-{
-	struct sysfs_dirent * sd = dentry->d_fsdata;
-
-	sysfs_put(sd);
-	iput(inode);
-}
-
-static struct dentry_operations sysfs_dentry_ops = {
-	.d_iput		= sysfs_d_iput,
-};
-
-struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
-{
-	char *dup_name = NULL;
-	struct sysfs_dirent *sd;
-
-	if (type & SYSFS_COPY_NAME) {
-		name = dup_name = kstrdup(name, GFP_KERNEL);
-		if (!name)
-			return NULL;
-	}
-
-	sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
-	if (!sd)
-		goto err_out1;
-
-	if (sysfs_alloc_ino(&sd->s_ino))
-		goto err_out2;
-
-	atomic_set(&sd->s_count, 1);
-	atomic_set(&sd->s_active, 0);
-
-	sd->s_name = name;
-	sd->s_mode = mode;
-	sd->s_flags = type;
-
-	return sd;
-
- err_out2:
-	kmem_cache_free(sysfs_dir_cachep, sd);
- err_out1:
-	kfree(dup_name);
-	return NULL;
-}
-
-static int sysfs_ilookup_test(struct inode *inode, void *arg)
-{
-	struct sysfs_dirent *sd = arg;
-	return inode->i_ino == sd->s_ino;
-}
-
-/**
- *	sysfs_addrm_start - prepare for sysfs_dirent add/remove
- *	@acxt: pointer to sysfs_addrm_cxt to be used
- *	@parent_sd: parent sysfs_dirent
- *
- *	This function is called when the caller is about to add or
- *	remove sysfs_dirent under @parent_sd.  This function acquires
- *	sysfs_mutex, grabs inode for @parent_sd if available and lock
- *	i_mutex of it.  @acxt is used to keep and pass context to
- *	other addrm functions.
- *
- *	LOCKING:
- *	Kernel thread context (may sleep).  sysfs_mutex is locked on
- *	return.  i_mutex of parent inode is locked on return if
- *	available.
- */
-void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,
-		       struct sysfs_dirent *parent_sd)
-{
-	struct inode *inode;
-
-	memset(acxt, 0, sizeof(*acxt));
-	acxt->parent_sd = parent_sd;
-
-	/* Lookup parent inode.  inode initialization and I_NEW
-	 * clearing are protected by sysfs_mutex.  By grabbing it and
-	 * looking up with _nowait variant, inode state can be
-	 * determined reliably.
-	 */
-	mutex_lock(&sysfs_mutex);
-
-	inode = ilookup5_nowait(sysfs_sb, parent_sd->s_ino, sysfs_ilookup_test,
-				parent_sd);
-
-	if (inode && !(inode->i_state & I_NEW)) {
-		/* parent inode available */
-		acxt->parent_inode = inode;
-
-		/* sysfs_mutex is below i_mutex in lock hierarchy.
-		 * First, trylock i_mutex.  If fails, unlock
-		 * sysfs_mutex and lock them in order.
-		 */
-		if (!mutex_trylock(&inode->i_mutex)) {
-			mutex_unlock(&sysfs_mutex);
-			mutex_lock(&inode->i_mutex);
-			mutex_lock(&sysfs_mutex);
-		}
-	} else
-		iput(inode);
-}
-
-/**
- *	sysfs_add_one - add sysfs_dirent to parent
- *	@acxt: addrm context to use
- *	@sd: sysfs_dirent to be added
- *
- *	Get @acxt->parent_sd and set sd->s_parent to it and increment
- *	nlink of parent inode if @sd is a directory and link into the
- *	children list of the parent.
- *
- *	This function should be called between calls to
- *	sysfs_addrm_start() and sysfs_addrm_finish() and should be
- *	passed the same @acxt as passed to sysfs_addrm_start().
- *
- *	LOCKING:
- *	Determined by sysfs_addrm_start().
- *
- *	RETURNS:
- *	0 on success, -EEXIST if entry with the given name already
- *	exists.
- */
-int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
-{
-	if (sysfs_find_dirent(acxt->parent_sd, sd->s_name)) {
-		printk(KERN_WARNING "sysfs: duplicate filename '%s' "
-		       "can not be created\n", sd->s_name);
-		WARN_ON(1);
-		return -EEXIST;
-	}
-
-	sd->s_parent = sysfs_get(acxt->parent_sd);
-
-	if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode)
-		inc_nlink(acxt->parent_inode);
-
-	acxt->cnt++;
-
-	sysfs_link_sibling(sd);
-
-	return 0;
-}
-
-/**
- *	sysfs_remove_one - remove sysfs_dirent from parent
- *	@acxt: addrm context to use
- *	@sd: sysfs_dirent to be removed
- *
- *	Mark @sd removed and drop nlink of parent inode if @sd is a
- *	directory.  @sd is unlinked from the children list.
- *
- *	This function should be called between calls to
- *	sysfs_addrm_start() and sysfs_addrm_finish() and should be
- *	passed the same @acxt as passed to sysfs_addrm_start().
- *
- *	LOCKING:
- *	Determined by sysfs_addrm_start().
- */
-void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
-{
-	BUG_ON(sd->s_flags & SYSFS_FLAG_REMOVED);
-
-	sysfs_unlink_sibling(sd);
-
-	sd->s_flags |= SYSFS_FLAG_REMOVED;
-	sd->s_sibling = acxt->removed;
-	acxt->removed = sd;
-
-	if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode)
-		drop_nlink(acxt->parent_inode);
-
-	acxt->cnt++;
-}
-
-/**
- *	sysfs_drop_dentry - drop dentry for the specified sysfs_dirent
- *	@sd: target sysfs_dirent
- *
- *	Drop dentry for @sd.  @sd must have been unlinked from its
- *	parent on entry to this function such that it can't be looked
- *	up anymore.
- */
-static void sysfs_drop_dentry(struct sysfs_dirent *sd)
+void sysfs_warn_dup(struct kernfs_node *parent, const char *name)
 {
-	struct inode *inode;
-	struct dentry *dentry;
-
-	inode = ilookup(sysfs_sb, sd->s_ino);
-	if (!inode)
-		return;
-
-	/* Drop any existing dentries associated with sd.
-	 *
-	 * For the dentry to be properly freed we need to grab a
-	 * reference to the dentry under the dcache lock,  unhash it,
-	 * and then put it.  The playing with the dentry count allows
-	 * dput to immediately free the dentry  if it is not in use.
-	 */
-repeat:
-	spin_lock(&dcache_lock);
-	list_for_each_entry(dentry, &inode->i_dentry, d_alias) {
-		if (d_unhashed(dentry))
-			continue;
-		dget_locked(dentry);
-		spin_lock(&dentry->d_lock);
-		__d_drop(dentry);
-		spin_unlock(&dentry->d_lock);
-		spin_unlock(&dcache_lock);
-		dput(dentry);
-		goto repeat;
-	}
-	spin_unlock(&dcache_lock);
-
-	/* adjust nlink and update timestamp */
-	mutex_lock(&inode->i_mutex);
+	char *buf, *path = NULL;
 
-	inode->i_ctime = CURRENT_TIME;
-	drop_nlink(inode);
-	if (sysfs_type(sd) == SYSFS_DIR)
-		drop_nlink(inode);
-
-	mutex_unlock(&inode->i_mutex);
-
-	iput(inode);
-}
-
-/**
- *	sysfs_addrm_finish - finish up sysfs_dirent add/remove
- *	@acxt: addrm context to finish up
- *
- *	Finish up sysfs_dirent add/remove.  Resources acquired by
- *	sysfs_addrm_start() are released and removed sysfs_dirents are
- *	cleaned up.  Timestamps on the parent inode are updated.
- *
- *	LOCKING:
- *	All mutexes acquired by sysfs_addrm_start() are released.
- */
-void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt)
-{
-	/* release resources acquired by sysfs_addrm_start() */
-	mutex_unlock(&sysfs_mutex);
-	if (acxt->parent_inode) {
-		struct inode *inode = acxt->parent_inode;
+	buf = kzalloc(PATH_MAX, GFP_KERNEL);
+	if (buf)
+		path = kernfs_path(parent, buf, PATH_MAX);
 
-		/* if added/removed, update timestamps on the parent */
-		if (acxt->cnt)
-			inode->i_ctime = inode->i_mtime = CURRENT_TIME;
+	WARN(1, KERN_WARNING "sysfs: cannot create duplicate filename '%s/%s'\n",
+	     path, name);
 
-		mutex_unlock(&inode->i_mutex);
-		iput(inode);
-	}
-
-	/* kill removed sysfs_dirents */
-	while (acxt->removed) {
-		struct sysfs_dirent *sd = acxt->removed;
-
-		acxt->removed = sd->s_sibling;
-		sd->s_sibling = NULL;
-
-		sysfs_drop_dentry(sd);
-		sysfs_deactivate(sd);
-		sysfs_put(sd);
-	}
-}
-
-/**
- *	sysfs_find_dirent - find sysfs_dirent with the given name
- *	@parent_sd: sysfs_dirent to search under
- *	@name: name to look for
- *
- *	Look for sysfs_dirent with name @name under @parent_sd.
- *
- *	LOCKING:
- *	mutex_lock(sysfs_mutex)
- *
- *	RETURNS:
- *	Pointer to sysfs_dirent if found, NULL if not.
- */
-struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
-				       const unsigned char *name)
-{
-	struct sysfs_dirent *sd;
-
-	for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling)
-		if (!strcmp(sd->s_name, name))
-			return sd;
-	return NULL;
-}
-
-/**
- *	sysfs_get_dirent - find and get sysfs_dirent with the given name
- *	@parent_sd: sysfs_dirent to search under
- *	@name: name to look for
- *
- *	Look for sysfs_dirent with name @name under @parent_sd and get
- *	it if found.
- *
- *	LOCKING:
- *	Kernel thread context (may sleep).  Grabs sysfs_mutex.
- *
- *	RETURNS:
- *	Pointer to sysfs_dirent if found, NULL if not.
- */
-struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
-				      const unsigned char *name)
-{
-	struct sysfs_dirent *sd;
-
-	mutex_lock(&sysfs_mutex);
-	sd = sysfs_find_dirent(parent_sd, name);
-	sysfs_get(sd);
-	mutex_unlock(&sysfs_mutex);
-
-	return sd;
-}
-
-static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
-		      const char *name, struct sysfs_dirent **p_sd)
-{
-	umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
-	struct sysfs_addrm_cxt acxt;
-	struct sysfs_dirent *sd;
-	int rc;
-
-	/* allocate */
-	sd = sysfs_new_dirent(name, mode, SYSFS_DIR);
-	if (!sd)
-		return -ENOMEM;
-	sd->s_dir.kobj = kobj;
-
-	/* link in */
-	sysfs_addrm_start(&acxt, parent_sd);
-	rc = sysfs_add_one(&acxt, sd);
-	sysfs_addrm_finish(&acxt);
-
-	if (rc == 0)
-		*p_sd = sd;
-	else
-		sysfs_put(sd);
-
-	return rc;
-}
-
-int sysfs_create_subdir(struct kobject *kobj, const char *name,
-			struct sysfs_dirent **p_sd)
-{
-	return create_dir(kobj, kobj->sd, name, p_sd);
+	kfree(buf);
 }
 
 /**
- *	sysfs_create_dir - create a directory for an object.
- *	@kobj:		object we're creating directory for. 
+ * sysfs_create_dir_ns - create a directory for an object with a namespace tag
+ * @kobj: object we're creating directory for
+ * @ns: the namespace tag to use
  */
-int sysfs_create_dir(struct kobject * kobj)
+int sysfs_create_dir_ns(struct kobject *kobj, const void *ns)
 {
-	struct sysfs_dirent *parent_sd, *sd;
-	int error = 0;
+	struct kernfs_node *parent, *kn;
 
 	BUG_ON(!kobj);
 
 	if (kobj->parent)
-		parent_sd = kobj->parent->sd;
+		parent = kobj->parent->sd;
 	else
-		parent_sd = &sysfs_root;
+		parent = sysfs_root_kn;
 
-	error = create_dir(kobj, parent_sd, kobject_name(kobj), &sd);
-	if (!error)
-		kobj->sd = sd;
-	return error;
-}
-
-static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
-				struct nameidata *nd)
-{
-	struct dentry *ret = NULL;
-	struct sysfs_dirent *parent_sd = dentry->d_parent->d_fsdata;
-	struct sysfs_dirent *sd;
-	struct inode *inode;
-
-	mutex_lock(&sysfs_mutex);
-
-	sd = sysfs_find_dirent(parent_sd, dentry->d_name.name);
+	if (!parent)
+		return -ENOENT;
 
-	/* no such entry */
-	if (!sd) {
-		ret = ERR_PTR(-ENOENT);
-		goto out_unlock;
+	kn = kernfs_create_dir_ns(parent, kobject_name(kobj),
+				  S_IRWXU | S_IRUGO | S_IXUGO, kobj, ns);
+	if (IS_ERR(kn)) {
+		if (PTR_ERR(kn) == -EEXIST)
+			sysfs_warn_dup(parent, kobject_name(kobj));
+		return PTR_ERR(kn);
 	}
 
-	/* attach dentry and inode */
-	inode = sysfs_get_inode(sd);
-	if (!inode) {
-		ret = ERR_PTR(-ENOMEM);
-		goto out_unlock;
-	}
-
-	/* instantiate and hash dentry */
-	dentry->d_op = &sysfs_dentry_ops;
-	dentry->d_fsdata = sysfs_get(sd);
-	d_instantiate(dentry, inode);
-	d_rehash(dentry);
-
- out_unlock:
-	mutex_unlock(&sysfs_mutex);
-	return ret;
-}
-
-const struct inode_operations sysfs_dir_inode_operations = {
-	.lookup		= sysfs_lookup,
-	.setattr	= sysfs_setattr,
-};
-
-static void remove_dir(struct sysfs_dirent *sd)
-{
-	struct sysfs_addrm_cxt acxt;
-
-	sysfs_addrm_start(&acxt, sd->s_parent);
-	sysfs_remove_one(&acxt, sd);
-	sysfs_addrm_finish(&acxt);
-}
-
-void sysfs_remove_subdir(struct sysfs_dirent *sd)
-{
-	remove_dir(sd);
-}
-
-
-static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd)
-{
-	struct sysfs_addrm_cxt acxt;
-	struct sysfs_dirent **pos;
-
-	if (!dir_sd)
-		return;
-
-	pr_debug("sysfs %s: removing dir\n", dir_sd->s_name);
-	sysfs_addrm_start(&acxt, dir_sd);
-	pos = &dir_sd->s_dir.children;
-	while (*pos) {
-		struct sysfs_dirent *sd = *pos;
-
-		if (sysfs_type(sd) != SYSFS_DIR)
-			sysfs_remove_one(&acxt, sd);
-		else
-			pos = &(*pos)->s_sibling;
-	}
-	sysfs_addrm_finish(&acxt);
-
-	remove_dir(dir_sd);
+	kobj->sd = kn;
+	return 0;
 }
 
 /**
@@ -753,211 +72,52 @@ static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd)
  *	the directory before we remove the directory, and we've inlined
  *	what used to be sysfs_rmdir() below, instead of calling separately.
  */
-
-void sysfs_remove_dir(struct kobject * kobj)
+void sysfs_remove_dir(struct kobject *kobj)
 {
-	struct sysfs_dirent *sd = kobj->sd;
+	struct kernfs_node *kn = kobj->sd;
 
-	spin_lock(&sysfs_assoc_lock);
+	/*
+	 * In general, kboject owner is responsible for ensuring removal
+	 * doesn't race with other operations and sysfs doesn't provide any
+	 * protection; however, when @kobj is used as a symlink target, the
+	 * symlinking entity usually doesn't own @kobj and thus has no
+	 * control over removal.  @kobj->sd may be removed anytime
+	 * and symlink code may end up dereferencing an already freed node.
+	 *
+	 * sysfs_symlink_target_lock synchronizes @kobj->sd
+	 * disassociation against symlink operations so that symlink code
+	 * can safely dereference @kobj->sd.
+	 */
+	spin_lock(&sysfs_symlink_target_lock);
 	kobj->sd = NULL;
-	spin_unlock(&sysfs_assoc_lock);
-
-	__sysfs_remove_dir(sd);
-}
-
-int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
-{
-	struct sysfs_dirent *sd = kobj->sd;
-	struct dentry *parent = NULL;
-	struct dentry *old_dentry = NULL, *new_dentry = NULL;
-	const char *dup_name = NULL;
-	int error;
-
-	mutex_lock(&sysfs_rename_mutex);
+	spin_unlock(&sysfs_symlink_target_lock);
 
-	error = 0;
-	if (strcmp(sd->s_name, new_name) == 0)
-		goto out;	/* nothing to rename */
-
-	/* get the original dentry */
-	old_dentry = sysfs_get_dentry(sd);
-	if (IS_ERR(old_dentry)) {
-		error = PTR_ERR(old_dentry);
-		old_dentry = NULL;
-		goto out;
+	if (kn) {
+		WARN_ON_ONCE(kernfs_type(kn) != KERNFS_DIR);
+		kernfs_remove(kn);
 	}
-
-	parent = old_dentry->d_parent;
-
-	/* lock parent and get dentry for new name */
-	mutex_lock(&parent->d_inode->i_mutex);
-	mutex_lock(&sysfs_mutex);
-
-	error = -EEXIST;
-	if (sysfs_find_dirent(sd->s_parent, new_name))
-		goto out_unlock;
-
-	error = -ENOMEM;
-	new_dentry = d_alloc_name(parent, new_name);
-	if (!new_dentry)
-		goto out_unlock;
-
-	/* rename kobject and sysfs_dirent */
-	error = -ENOMEM;
-	new_name = dup_name = kstrdup(new_name, GFP_KERNEL);
-	if (!new_name)
-		goto out_unlock;
-
-	error = kobject_set_name(kobj, "%s", new_name);
-	if (error)
-		goto out_unlock;
-
-	dup_name = sd->s_name;
-	sd->s_name = new_name;
-
-	/* rename */
-	d_add(new_dentry, NULL);
-	d_move(old_dentry, new_dentry);
-
-	error = 0;
- out_unlock:
-	mutex_unlock(&sysfs_mutex);
-	mutex_unlock(&parent->d_inode->i_mutex);
-	kfree(dup_name);
-	dput(old_dentry);
-	dput(new_dentry);
- out:
-	mutex_unlock(&sysfs_rename_mutex);
-	return error;
 }
 
-int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
+int sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name,
+			const void *new_ns)
 {
-	struct sysfs_dirent *sd = kobj->sd;
-	struct sysfs_dirent *new_parent_sd;
-	struct dentry *old_parent, *new_parent = NULL;
-	struct dentry *old_dentry = NULL, *new_dentry = NULL;
-	int error;
-
-	mutex_lock(&sysfs_rename_mutex);
-	BUG_ON(!sd->s_parent);
-	new_parent_sd = new_parent_kobj->sd ? new_parent_kobj->sd : &sysfs_root;
-
-	error = 0;
-	if (sd->s_parent == new_parent_sd)
-		goto out;	/* nothing to move */
-
-	/* get dentries */
-	old_dentry = sysfs_get_dentry(sd);
-	if (IS_ERR(old_dentry)) {
-		error = PTR_ERR(old_dentry);
-		old_dentry = NULL;
-		goto out;
-	}
-	old_parent = old_dentry->d_parent;
-
-	new_parent = sysfs_get_dentry(new_parent_sd);
-	if (IS_ERR(new_parent)) {
-		error = PTR_ERR(new_parent);
-		new_parent = NULL;
-		goto out;
-	}
-
-again:
-	mutex_lock(&old_parent->d_inode->i_mutex);
-	if (!mutex_trylock(&new_parent->d_inode->i_mutex)) {
-		mutex_unlock(&old_parent->d_inode->i_mutex);
-		goto again;
-	}
-	mutex_lock(&sysfs_mutex);
+	struct kernfs_node *parent;
+	int ret;
 
-	error = -EEXIST;
-	if (sysfs_find_dirent(new_parent_sd, sd->s_name))
-		goto out_unlock;
-
-	error = -ENOMEM;
-	new_dentry = d_alloc_name(new_parent, sd->s_name);
-	if (!new_dentry)
-		goto out_unlock;
-
-	error = 0;
-	d_add(new_dentry, NULL);
-	d_move(old_dentry, new_dentry);
-
-	/* Remove from old parent's list and insert into new parent's list. */
-	sysfs_unlink_sibling(sd);
-	sysfs_get(new_parent_sd);
-	sysfs_put(sd->s_parent);
-	sd->s_parent = new_parent_sd;
-	sysfs_link_sibling(sd);
-
- out_unlock:
-	mutex_unlock(&sysfs_mutex);
-	mutex_unlock(&new_parent->d_inode->i_mutex);
-	mutex_unlock(&old_parent->d_inode->i_mutex);
- out:
-	dput(new_parent);
-	dput(old_dentry);
-	dput(new_dentry);
-	mutex_unlock(&sysfs_rename_mutex);
-	return error;
+	parent = kernfs_get_parent(kobj->sd);
+	ret = kernfs_rename_ns(kobj->sd, parent, new_name, new_ns);
+	kernfs_put(parent);
+	return ret;
 }
 
-/* Relationship between s_mode and the DT_xxx types */
-static inline unsigned char dt_type(struct sysfs_dirent *sd)
+int sysfs_move_dir_ns(struct kobject *kobj, struct kobject *new_parent_kobj,
+		      const void *new_ns)
 {
-	return (sd->s_mode >> 12) & 15;
-}
+	struct kernfs_node *kn = kobj->sd;
+	struct kernfs_node *new_parent;
 
-static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
-{
-	struct dentry *dentry = filp->f_path.dentry;
-	struct sysfs_dirent * parent_sd = dentry->d_fsdata;
-	struct sysfs_dirent *pos;
-	ino_t ino;
+	new_parent = new_parent_kobj && new_parent_kobj->sd ?
+		new_parent_kobj->sd : sysfs_root_kn;
 
-	if (filp->f_pos == 0) {
-		ino = parent_sd->s_ino;
-		if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) == 0)
-			filp->f_pos++;
-	}
-	if (filp->f_pos == 1) {
-		if (parent_sd->s_parent)
-			ino = parent_sd->s_parent->s_ino;
-		else
-			ino = parent_sd->s_ino;
-		if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) == 0)
-			filp->f_pos++;
-	}
-	if ((filp->f_pos > 1) && (filp->f_pos < INT_MAX)) {
-		mutex_lock(&sysfs_mutex);
-
-		/* Skip the dentries we have already reported */
-		pos = parent_sd->s_dir.children;
-		while (pos && (filp->f_pos > pos->s_ino))
-			pos = pos->s_sibling;
-
-		for ( ; pos; pos = pos->s_sibling) {
-			const char * name;
-			int len;
-
-			name = pos->s_name;
-			len = strlen(name);
-			filp->f_pos = ino = pos->s_ino;
-
-			if (filldir(dirent, name, len, filp->f_pos, ino,
-					 dt_type(pos)) < 0)
-				break;
-		}
-		if (!pos)
-			filp->f_pos = INT_MAX;
-		mutex_unlock(&sysfs_mutex);
-	}
-	return 0;
+	return kernfs_rename_ns(kn, new_parent, kn->name, new_ns);
 }
-
-
-const struct file_operations sysfs_dir_operations = {
-	.read		= generic_read_dir,
-	.readdir	= sysfs_readdir,
-};