move d_rcu from overlapping d_child to overlapping d_alias

commit 946e51f2 upstream.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[bwh: Backported to 3.2:
 - Apply name changes in all the different places we use d_alias and d_child
 - Move the WARN_ON() in __d_free() to d_free() as we don't have dentry_free()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

arch/powerpc/platforms/cell/spufs/inode.c

@@ -165,7 +165,7 @@ static void spufs_prune_dir(struct dentry *dir)
 	struct dentry *dentry, *tmp;
 
 	mutex_lock(&dir->d_inode->i_mutex);
-	list_for_each_entry_safe(dentry, tmp, &dir->d_subdirs, d_u.d_child) {
+	list_for_each_entry_safe(dentry, tmp, &dir->d_subdirs, d_child) {
 		spin_lock(&dentry->d_lock);
 		if (!(d_unhashed(dentry)) && dentry->d_inode) {
 			dget_dlock(dentry);
@@ -223,7 +223,7 @@ static int spufs_fill_dir(struct dentry *dir,
 	 * - free child's inode if possible
 	 * - free child
 	 */
-	list_for_each_entry_safe(dentry, tmp, &dir->d_subdirs, d_u.d_child) {
+	list_for_each_entry_safe(dentry, tmp, &dir->d_subdirs, d_child) {
 		dput(dentry);
 	}
 

drivers/usb/core/inode.c

@@ -212,7 +212,7 @@ static void update_bus(struct dentry *bus)
 
 	mutex_lock(&bus->d_inode->i_mutex);
 
-	list_for_each_entry(dev, &bus->d_subdirs, d_u.d_child)
+	list_for_each_entry(dev, &bus->d_subdirs, d_child)
 		if (dev->d_inode)
 			update_dev(dev);
 
@@ -229,7 +229,7 @@ static void update_sb(struct super_block *sb)
 
 	mutex_lock_nested(&root->d_inode->i_mutex, I_MUTEX_PARENT);
 
-	list_for_each_entry(bus, &root->d_subdirs, d_u.d_child) {
+	list_for_each_entry(bus, &root->d_subdirs, d_child) {
 		if (bus->d_inode) {
 			switch (S_IFMT & bus->d_inode->i_mode) {
 			case S_IFDIR:
@@ -345,7 +345,7 @@ static int usbfs_empty (struct dentry *dentry)
 
 	spin_lock(&dentry->d_lock);
 	list_for_each(list, &dentry->d_subdirs) {
-		struct dentry *de = list_entry(list, struct dentry, d_u.d_child);
+		struct dentry *de = list_entry(list, struct dentry, d_child);
 
 		spin_lock_nested(&de->d_lock, DENTRY_D_LOCK_NESTED);
 		if (usbfs_positive(de)) {

fs/9p/vfs_inode_dotl.c

@@ -81,7 +81,7 @@ static struct dentry *v9fs_dentry_from_dir_inode(struct inode *inode)
 	spin_lock(&inode->i_lock);
 	/* Directory should have only one entry. */
 	BUG_ON(S_ISDIR(inode->i_mode) && !list_is_singular(&inode->i_dentry));
-	dentry = list_entry(inode->i_dentry.next, struct dentry, d_alias);
+	dentry = list_entry(inode->i_dentry.next, struct dentry, d_u.d_alias);
 	spin_unlock(&inode->i_lock);
 	return dentry;
 }

fs/affs/amigaffs.c

@@ -132,7 +132,7 @@ affs_fix_dcache(struct dentry *dentry, u32 entry_ino)
 	head = &inode->i_dentry;
 	next = head->next;
 	while (next != head) {
-		dentry = list_entry(next, struct dentry, d_alias);
+		dentry = list_entry(next, struct dentry, d_u.d_alias);
 		if (entry_ino == (u32)(long)dentry->d_fsdata) {
 			dentry->d_fsdata = data;
 			break;

fs/autofs4/expire.c

@@ -100,7 +100,7 @@ static struct dentry *get_next_positive_subdir(struct dentry *prev,
 	p = prev;
 	spin_lock(&p->d_lock);
 again:
-	next = p->d_u.d_child.next;
+	next = p->d_child.next;
 start:
 	if (next == &root->d_subdirs) {
 		spin_unlock(&p->d_lock);
@@ -109,7 +109,7 @@ static struct dentry *get_next_positive_subdir(struct dentry *prev,
 		return NULL;
 	}
 
-	q = list_entry(next, struct dentry, d_u.d_child);
+	q = list_entry(next, struct dentry, d_child);
 
 	spin_lock_nested(&q->d_lock, DENTRY_D_LOCK_NESTED);
 	/* Negative dentry - try next */
@@ -165,13 +165,13 @@ static struct dentry *get_next_positive_dentry(struct dentry *prev,
 				goto relock;
 			}
 			spin_unlock(&p->d_lock);
-			next = p->d_u.d_child.next;
+			next = p->d_child.next;
 			p = parent;
 			if (next != &parent->d_subdirs)
 				break;
 		}
 	}
-	ret = list_entry(next, struct dentry, d_u.d_child);
+	ret = list_entry(next, struct dentry, d_child);
 
 	spin_lock_nested(&ret->d_lock, DENTRY_D_LOCK_NESTED);
 	/* Negative dentry - try next */
@@ -455,7 +455,7 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb,
 	spin_lock(&sbi->lookup_lock);
 	spin_lock(&expired->d_parent->d_lock);
 	spin_lock_nested(&expired->d_lock, DENTRY_D_LOCK_NESTED);
-	list_move(&expired->d_parent->d_subdirs, &expired->d_u.d_child);
+	list_move(&expired->d_parent->d_subdirs, &expired->d_child);
 	spin_unlock(&expired->d_lock);
 	spin_unlock(&expired->d_parent->d_lock);
 	spin_unlock(&sbi->lookup_lock);

fs/autofs4/root.c

@@ -651,7 +651,7 @@ static void autofs_clear_leaf_automount_flags(struct dentry *dentry)
 	/* only consider parents below dentrys in the root */
 	if (IS_ROOT(parent->d_parent))
 		return;
-	d_child = &dentry->d_u.d_child;
+	d_child = &dentry->d_child;
 	/* Set parent managed if it's becoming empty */
 	if (d_child->next == &parent->d_subdirs &&
 	    d_child->prev == &parent->d_subdirs)

fs/ceph/dir.c

@@ -104,7 +104,7 @@ static unsigned fpos_off(loff_t p)
 /*
  * When possible, we try to satisfy a readdir by peeking at the
  * dcache.  We make this work by carefully ordering dentries on
- * d_u.d_child when we initially get results back from the MDS, and
+ * d_child when we initially get results back from the MDS, and
  * falling back to a "normal" sync readdir if any dentries in the dir
  * are dropped.
  *
@@ -140,11 +140,11 @@ static int __dcache_readdir(struct file *filp,
 		p = parent->d_subdirs.prev;
 		dout(" initial p %p/%p\n", p->prev, p->next);
 	} else {
-		p = last->d_u.d_child.prev;
+		p = last->d_child.prev;
 	}
 
 more:
-	dentry = list_entry(p, struct dentry, d_u.d_child);
+	dentry = list_entry(p, struct dentry, d_child);
 	di = ceph_dentry(dentry);
 	while (1) {
 		dout(" p %p/%p %s d_subdirs %p/%p\n", p->prev, p->next,
@@ -166,7 +166,7 @@ static int __dcache_readdir(struct file *filp,
 		     !dentry->d_inode ? " null" : "");
 		spin_unlock(&dentry->d_lock);
 		p = p->prev;
-		dentry = list_entry(p, struct dentry, d_u.d_child);
+		dentry = list_entry(p, struct dentry, d_child);
 		di = ceph_dentry(dentry);
 	}
 

fs/ceph/inode.c

@@ -868,9 +868,9 @@ static void ceph_set_dentry_offset(struct dentry *dn)
 
 	spin_lock(&dir->d_lock);
 	spin_lock_nested(&dn->d_lock, DENTRY_D_LOCK_NESTED);
-	list_move(&dn->d_u.d_child, &dir->d_subdirs);
+	list_move(&dn->d_child, &dir->d_subdirs);
 	dout("set_dentry_offset %p %lld (%p %p)\n", dn, di->offset,
-	     dn->d_u.d_child.prev, dn->d_u.d_child.next);
+	     dn->d_child.prev, dn->d_child.next);
 	spin_unlock(&dn->d_lock);
 	spin_unlock(&dir->d_lock);
 }
@@ -1256,7 +1256,7 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req,
 			/* reorder parent's d_subdirs */
 			spin_lock(&parent->d_lock);
 			spin_lock_nested(&dn->d_lock, DENTRY_D_LOCK_NESTED);
-			list_move(&dn->d_u.d_child, &parent->d_subdirs);
+			list_move(&dn->d_child, &parent->d_subdirs);
 			spin_unlock(&dn->d_lock);
 			spin_unlock(&parent->d_lock);
 		}

fs/cifs/inode.c

@@ -823,7 +823,7 @@ inode_has_hashed_dentries(struct inode *inode)
 	struct dentry *dentry;
 
 	spin_lock(&inode->i_lock);
-	list_for_each_entry(dentry, &inode->i_dentry, d_alias) {
+	list_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
 		if (!d_unhashed(dentry) || IS_ROOT(dentry)) {
 			spin_unlock(&inode->i_lock);
 			return true;

fs/coda/cache.c

@@ -95,7 +95,7 @@ static void coda_flag_children(struct dentry *parent, int flag)
 	spin_lock(&parent->d_lock);
 	list_for_each(child, &parent->d_subdirs)
 	{
-		de = list_entry(child, struct dentry, d_u.d_child);
+		de = list_entry(child, struct dentry, d_child);
 		/* don't know what to do with negative dentries */
 		if ( ! de->d_inode ) 
 			continue;

fs/dcache.c

@@ -42,7 +42,7 @@
 /*
  * Usage:
  * dcache->d_inode->i_lock protects:
- *   - i_dentry, d_alias, d_inode of aliases
+ *   - i_dentry, d_u.d_alias, d_inode of aliases
  * dcache_hash_bucket lock protects:
  *   - the dcache hash table
  * s_anon bl list spinlock protects:
@@ -57,7 +57,7 @@
  *   - d_unhashed()
  *   - d_parent and d_subdirs
  *   - childrens' d_child and d_parent
- *   - d_alias, d_inode
+ *   - d_u.d_alias, d_inode
  *
  * Ordering:
  * dentry->d_inode->i_lock
@@ -140,7 +140,6 @@ static void __d_free(struct rcu_head *head)
 {
 	struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu);
 
-	WARN_ON(!list_empty(&dentry->d_alias));
 	if (dname_external(dentry))
 		kfree(dentry->d_name.name);
 	kmem_cache_free(dentry_cache, dentry); 
@@ -151,6 +150,7 @@ static void __d_free(struct rcu_head *head)
  */
 static void d_free(struct dentry *dentry)
 {
+	WARN_ON(!list_empty(&dentry->d_u.d_alias));
 	BUG_ON(dentry->d_count);
 	this_cpu_dec(nr_dentry);
 	if (dentry->d_op && dentry->d_op->d_release)
@@ -189,7 +189,7 @@ static void dentry_iput(struct dentry * dentry)
 	struct inode *inode = dentry->d_inode;
 	if (inode) {
 		dentry->d_inode = NULL;
-		list_del_init(&dentry->d_alias);
+		list_del_init(&dentry->d_u.d_alias);
 		spin_unlock(&dentry->d_lock);
 		spin_unlock(&inode->i_lock);
 		if (!inode->i_nlink)
@@ -213,7 +213,7 @@ static void dentry_unlink_inode(struct dentry * dentry)
 {
 	struct inode *inode = dentry->d_inode;
 	dentry->d_inode = NULL;
-	list_del_init(&dentry->d_alias);
+	list_del_init(&dentry->d_u.d_alias);
 	dentry_rcuwalk_barrier(dentry);
 	spin_unlock(&dentry->d_lock);
 	spin_unlock(&inode->i_lock);
@@ -306,7 +306,7 @@ static struct dentry *d_kill(struct dentry *dentry, struct dentry *parent)
 	__releases(parent->d_lock)
 	__releases(dentry->d_inode->i_lock)
 {
-	list_del(&dentry->d_u.d_child);
+	list_del(&dentry->d_child);
 	/*
 	 * Inform try_to_ascend() that we are no longer attached to the
 	 * dentry tree
@@ -624,7 +624,7 @@ static struct dentry *__d_find_alias(struct inode *inode, int want_discon)
 
 again:
 	discon_alias = NULL;
-	list_for_each_entry(alias, &inode->i_dentry, d_alias) {
+	list_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
 		spin_lock(&alias->d_lock);
  		if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) {
 			if (IS_ROOT(alias) &&
@@ -677,7 +677,7 @@ void d_prune_aliases(struct inode *inode)
 	struct dentry *dentry;
 restart:
 	spin_lock(&inode->i_lock);
-	list_for_each_entry(dentry, &inode->i_dentry, d_alias) {
+	list_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
 		spin_lock(&dentry->d_lock);
 		if (!dentry->d_count) {
 			__dget_dlock(dentry);
@@ -857,7 +857,7 @@ static void shrink_dcache_for_umount_subtree(struct dentry *dentry)
 		/* descend to the first leaf in the current subtree */
 		while (!list_empty(&dentry->d_subdirs))
 			dentry = list_entry(dentry->d_subdirs.next,
-					    struct dentry, d_u.d_child);
+					    struct dentry, d_child);
 
 		/* consume the dentries from this leaf up through its parents
 		 * until we find one with children or run out altogether */
@@ -889,17 +889,17 @@ static void shrink_dcache_for_umount_subtree(struct dentry *dentry)
 
 			if (IS_ROOT(dentry)) {
 				parent = NULL;
-				list_del(&dentry->d_u.d_child);
+				list_del(&dentry->d_child);
 			} else {
 				parent = dentry->d_parent;
 				parent->d_count--;
-				list_del(&dentry->d_u.d_child);
+				list_del(&dentry->d_child);
 			}
 
 			inode = dentry->d_inode;
 			if (inode) {
 				dentry->d_inode = NULL;
-				list_del_init(&dentry->d_alias);
+				list_del_init(&dentry->d_u.d_alias);
 				if (dentry->d_op && dentry->d_op->d_iput)
 					dentry->d_op->d_iput(dentry, inode);
 				else
@@ -917,7 +917,7 @@ static void shrink_dcache_for_umount_subtree(struct dentry *dentry)
 		} while (list_empty(&dentry->d_subdirs));
 
 		dentry = list_entry(dentry->d_subdirs.next,
-				    struct dentry, d_u.d_child);
+				    struct dentry, d_child);
 	}
 }
 
@@ -1010,7 +1010,7 @@ int have_submounts(struct dentry *parent)
 resume:
 	while (next != &this_parent->d_subdirs) {
 		struct list_head *tmp = next;
-		struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child);
+		struct dentry *dentry = list_entry(tmp, struct dentry, d_child);
 		next = tmp->next;
 
 		spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
@@ -1037,7 +1037,7 @@ int have_submounts(struct dentry *parent)
 		this_parent = try_to_ascend(this_parent, locked, seq);
 		if (!this_parent)
 			goto rename_retry;
-		next = child->d_u.d_child.next;
+		next = child->d_child.next;
 		goto resume;
 	}
 	spin_unlock(&this_parent->d_lock);
@@ -1093,7 +1093,7 @@ static int select_parent(struct dentry *parent, struct list_head *dispose)
 resume:
 	while (next != &this_parent->d_subdirs) {
 		struct list_head *tmp = next;
-		struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child);
+		struct dentry *dentry = list_entry(tmp, struct dentry, d_child);
 		next = tmp->next;
 
 		spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
@@ -1144,7 +1144,7 @@ static int select_parent(struct dentry *parent, struct list_head *dispose)
 		this_parent = try_to_ascend(this_parent, locked, seq);
 		if (!this_parent)
 			goto rename_retry;
-		next = child->d_u.d_child.next;
+		next = child->d_child.next;
 		goto resume;
 	}
 out:
@@ -1230,8 +1230,8 @@ struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name)
 	INIT_HLIST_BL_NODE(&dentry->d_hash);
 	INIT_LIST_HEAD(&dentry->d_lru);
 	INIT_LIST_HEAD(&dentry->d_subdirs);
-	INIT_LIST_HEAD(&dentry->d_alias);
-	INIT_LIST_HEAD(&dentry->d_u.d_child);
+	INIT_LIST_HEAD(&dentry->d_u.d_alias);
+	INIT_LIST_HEAD(&dentry->d_child);
 	d_set_d_op(dentry, dentry->d_sb->s_d_op);
 
 	this_cpu_inc(nr_dentry);
@@ -1261,7 +1261,7 @@ struct dentry *d_alloc(struct dentry * parent, const struct qstr *name)
 	 */
 	__dget_dlock(parent);
 	dentry->d_parent = parent;
-	list_add(&dentry->d_u.d_child, &parent->d_subdirs);
+	list_add(&dentry->d_child, &parent->d_subdirs);
 	spin_unlock(&parent->d_lock);
 
 	return dentry;
@@ -1318,7 +1318,7 @@ static void __d_instantiate(struct dentry *dentry, struct inode *inode)
 	if (inode) {
 		if (unlikely(IS_AUTOMOUNT(inode)))
 			dentry->d_flags |= DCACHE_NEED_AUTOMOUNT;
-		list_add(&dentry->d_alias, &inode->i_dentry);
+		list_add(&dentry->d_u.d_alias, &inode->i_dentry);
 	}
 	dentry->d_inode = inode;
 	dentry_rcuwalk_barrier(dentry);
@@ -1343,7 +1343,7 @@ static void __d_instantiate(struct dentry *dentry, struct inode *inode)
  
 void d_instantiate(struct dentry *entry, struct inode * inode)
 {
-	BUG_ON(!list_empty(&entry->d_alias));
+	BUG_ON(!list_empty(&entry->d_u.d_alias));
 	if (inode)
 		spin_lock(&inode->i_lock);
 	__d_instantiate(entry, inode);
@@ -1382,7 +1382,7 @@ static struct dentry *__d_instantiate_unique(struct dentry *entry,
 		return NULL;
 	}
 
-	list_for_each_entry(alias, &inode->i_dentry, d_alias) {
+	list_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
 		struct qstr *qstr = &alias->d_name;
 
 		/*
@@ -1408,7 +1408,7 @@ struct dentry *d_instantiate_unique(struct dentry *entry, struct inode *inode)
 {
 	struct dentry *result;
 
-	BUG_ON(!list_empty(&entry->d_alias));
+	BUG_ON(!list_empty(&entry->d_u.d_alias));
 
 	if (inode)
 		spin_lock(&inode->i_lock);
@@ -1458,7 +1458,7 @@ static struct dentry * __d_find_any_alias(struct inode *inode)
 
 	if (list_empty(&inode->i_dentry))
 		return NULL;
-	alias = list_first_entry(&inode->i_dentry, struct dentry, d_alias);
+	alias = list_first_entry(&inode->i_dentry, struct dentry, d_u.d_alias);
 	__dget(alias);
 	return alias;
 }
@@ -1525,7 +1525,7 @@ struct dentry *d_obtain_alias(struct inode *inode)
 	spin_lock(&tmp->d_lock);
 	tmp->d_inode = inode;
 	tmp->d_flags |= DCACHE_DISCONNECTED;
-	list_add(&tmp->d_alias, &inode->i_dentry);
+	list_add(&tmp->d_u.d_alias, &inode->i_dentry);
 	hlist_bl_lock(&tmp->d_sb->s_anon);
 	hlist_bl_add_head(&tmp->d_hash, &tmp->d_sb->s_anon);
 	hlist_bl_unlock(&tmp->d_sb->s_anon);
@@ -1931,7 +1931,7 @@ int d_validate(struct dentry *dentry, struct dentry *dparent)
 	struct dentry *child;
 
 	spin_lock(&dparent->d_lock);
-	list_for_each_entry(child, &dparent->d_subdirs, d_u.d_child) {
+	list_for_each_entry(child, &dparent->d_subdirs, d_child) {
 		if (dentry == child) {
 			spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
 			__dget_dlock(dentry);
@@ -2178,8 +2178,8 @@ static void __d_move(struct dentry * dentry, struct dentry * target)
 	/* Unhash the target: dput() will then get rid of it */
 	__d_drop(target);
 
-	list_del(&dentry->d_u.d_child);
-	list_del(&target->d_u.d_child);
+	list_del(&dentry->d_child);
+	list_del(&target->d_child);
 
 	/* Switch the names.. */
 	switch_names(dentry, target);
@@ -2189,15 +2189,15 @@ static void __d_move(struct dentry * dentry, struct dentry * target)
 	if (IS_ROOT(dentry)) {
 		dentry->d_parent = target->d_parent;
 		target->d_parent = target;
-		INIT_LIST_HEAD(&target->d_u.d_child);
+		INIT_LIST_HEAD(&target->d_child);
 	} else {
 		swap(dentry->d_parent, target->d_parent);
 
 		/* And add them back to the (new) parent lists */
-		list_add(&target->d_u.d_child, &target->d_parent->d_subdirs);
+		list_add(&target->d_child, &target->d_parent->d_subdirs);
 	}
 
-	list_add(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs);
+	list_add(&dentry->d_child, &dentry->d_parent->d_subdirs);
 
 	write_seqcount_end(&target->d_seq);
 	write_seqcount_end(&dentry->d_seq);
@@ -2304,18 +2304,18 @@ static void __d_materialise_dentry(struct dentry *dentry, struct dentry *anon)
 	swap(dentry->d_name.hash, anon->d_name.hash);
 
 	dentry->d_parent = (aparent == anon) ? dentry : aparent;
-	list_del(&dentry->d_u.d_child);
+	list_del(&dentry->d_child);
 	if (!IS_ROOT(dentry))
-		list_add(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs);
+		list_add(&dentry->d_child, &dentry->d_parent->d_subdirs);
 	else
-		INIT_LIST_HEAD(&dentry->d_u.d_child);
+		INIT_LIST_HEAD(&dentry->d_child);
 
 	anon->d_parent = (dparent == dentry) ? anon : dparent;
-	list_del(&anon->d_u.d_child);
+	list_del(&anon->d_child);
 	if (!IS_ROOT(anon))
-		list_add(&anon->d_u.d_child, &anon->d_parent->d_subdirs);
+		list_add(&anon->d_child, &anon->d_parent->d_subdirs);
 	else
-		INIT_LIST_HEAD(&anon->d_u.d_child);
+		INIT_LIST_HEAD(&anon->d_child);
 
 	write_seqcount_end(&dentry->d_seq);
 	write_seqcount_end(&anon->d_seq);
@@ -2893,7 +2893,7 @@ void d_genocide(struct dentry *root)
 resume:
 	while (next != &this_parent->d_subdirs) {
 		struct list_head *tmp = next;
-		struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child);
+		struct dentry *dentry = list_entry(tmp, struct dentry, d_child);
 		next = tmp->next;
 
 		spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
@@ -2923,7 +2923,7 @@ void d_genocide(struct dentry *root)
 		this_parent = try_to_ascend(this_parent, locked, seq);
 		if (!this_parent)
 			goto rename_retry;
-		next = child->d_u.d_child.next;
+		next = child->d_child.next;
 		goto resume;
 	}
 	spin_unlock(&this_parent->d_lock);

fs/debugfs/inode.c

@@ -399,7 +399,7 @@ void debugfs_remove_recursive(struct dentry *dentry)
 	 * use the d_u.d_child as the rcu head and corrupt this list.
 	 */
 	spin_lock(&parent->d_lock);
-	list_for_each_entry(child, &parent->d_subdirs, d_u.d_child) {
+	list_for_each_entry(child, &parent->d_subdirs, d_child) {
 		if (!debugfs_positive(child))
 			continue;
 

fs/exportfs/expfs.c

@@ -50,7 +50,7 @@ find_acceptable_alias(struct dentry *result,
 
 	inode = result->d_inode;
 	spin_lock(&inode->i_lock);
-	list_for_each_entry(dentry, &inode->i_dentry, d_alias) {
+	list_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
 		dget(dentry);
 		spin_unlock(&inode->i_lock);
 		if (toput)

fs/ext4/fsync.c

@@ -139,7 +139,7 @@ static int ext4_sync_parent(struct inode *inode)
 		spin_lock(&inode->i_lock);
 		if (!list_empty(&inode->i_dentry)) {
 			dentry = list_first_entry(&inode->i_dentry,
-						  struct dentry, d_alias);
+						  struct dentry, d_u.d_alias);
 			dget(dentry);
 		}
 		spin_unlock(&inode->i_lock);

fs/libfs.c

@@ -104,18 +104,18 @@ loff_t dcache_dir_lseek(struct file *file, loff_t offset, int origin)
 
 			spin_lock(&dentry->d_lock);
 			/* d_lock not required for cursor */
-			list_del(&cursor->d_u.d_child);
+			list_del(&cursor->d_child);
 			p = dentry->d_subdirs.next;
 			while (n && p != &dentry->d_subdirs) {
 				struct dentry *next;
-				next = list_entry(p, struct dentry, d_u.d_child);
+				next = list_entry(p, struct dentry, d_child);
 				spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
 				if (simple_positive(next))
 					n--;
 				spin_unlock(&next->d_lock);
 				p = p->next;
 			}
-			list_add_tail(&cursor->d_u.d_child, p);
+			list_add_tail(&cursor->d_child, p);
 			spin_unlock(&dentry->d_lock);
 		}
 	}
@@ -139,7 +139,7 @@ int dcache_readdir(struct file * filp, void * dirent, filldir_t filldir)
 {
 	struct dentry *dentry = filp->f_path.dentry;
 	struct dentry *cursor = filp->private_data;
-	struct list_head *p, *q = &cursor->d_u.d_child;
+	struct list_head *p, *q = &cursor->d_child;
 	ino_t ino;
 	int i = filp->f_pos;
 
@@ -165,7 +165,7 @@ int dcache_readdir(struct file * filp, void * dirent, filldir_t filldir)
 
 			for (p=q->next; p != &dentry->d_subdirs; p=p->next) {
 				struct dentry *next;
-				next = list_entry(p, struct dentry, d_u.d_child);
+				next = list_entry(p, struct dentry, d_child);
 				spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
 				if (!simple_positive(next)) {
 					spin_unlock(&next->d_lock);
@@ -282,7 +282,7 @@ int simple_empty(struct dentry *dentry)
 	int ret = 0;
 
 	spin_lock(&dentry->d_lock);
-	list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child) {
+	list_for_each_entry(child, &dentry->d_subdirs, d_child) {
 		spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
 		if (simple_positive(child)) {
 			spin_unlock(&child->d_lock);

fs/ncpfs/dir.c

@@ -391,7 +391,7 @@ ncp_dget_fpos(struct dentry *dentry, struct dentry *parent, unsigned long fpos)
 	spin_lock(&parent->d_lock);
 	next = parent->d_subdirs.next;
 	while (next != &parent->d_subdirs) {
-		dent = list_entry(next, struct dentry, d_u.d_child);
+		dent = list_entry(next, struct dentry, d_child);
 		if ((unsigned long)dent->d_fsdata == fpos) {
 			if (dent->d_inode)
 				dget(dent);

fs/ncpfs/ncplib_kernel.h

@@ -194,7 +194,7 @@ ncp_renew_dentries(struct dentry *parent)
 	spin_lock(&parent->d_lock);
 	next = parent->d_subdirs.next;
 	while (next != &parent->d_subdirs) {
-		dentry = list_entry(next, struct dentry, d_u.d_child);
+		dentry = list_entry(next, struct dentry, d_child);
 
 		if (dentry->d_fsdata == NULL)
 			ncp_age_dentry(server, dentry);
@@ -216,7 +216,7 @@ ncp_invalidate_dircache_entries(struct dentry *parent)
 	spin_lock(&parent->d_lock);
 	next = parent->d_subdirs.next;
 	while (next != &parent->d_subdirs) {
-		dentry = list_entry(next, struct dentry, d_u.d_child);
+		dentry = list_entry(next, struct dentry, d_child);
 		dentry->d_fsdata = NULL;
 		ncp_age_dentry(server, dentry);
 		next = next->next;

fs/nfs/getroot.c

@@ -65,7 +65,7 @@ static int nfs_superblock_set_dummy_root(struct super_block *sb, struct inode *i
 		 */
 		spin_lock(&sb->s_root->d_inode->i_lock);
 		spin_lock(&sb->s_root->d_lock);
-		list_del_init(&sb->s_root->d_alias);
+		list_del_init(&sb->s_root->d_u.d_alias);
 		spin_unlock(&sb->s_root->d_lock);
 		spin_unlock(&sb->s_root->d_inode->i_lock);
 	}

fs/notify/fsnotify.c

@@ -62,14 +62,14 @@ void __fsnotify_update_child_dentry_flags(struct inode *inode)
 	spin_lock(&inode->i_lock);
 	/* run all of the dentries associated with this inode.  Since this is a
 	 * directory, there damn well better only be one item on this list */
-	list_for_each_entry(alias, &inode->i_dentry, d_alias) {
+	list_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
 		struct dentry *child;
 
 		/* run all of the children of the original inode and fix their
 		 * d_flags to indicate parental interest (their parent is the
 		 * original inode) */
 		spin_lock(&alias->d_lock);
-		list_for_each_entry(child, &alias->d_subdirs, d_u.d_child) {
+		list_for_each_entry(child, &alias->d_subdirs, d_child) {
 			if (!child->d_inode)
 				continue;
 

fs/ocfs2/dcache.c

@@ -175,7 +175,7 @@ struct dentry *ocfs2_find_local_alias(struct inode *inode,
 
 	spin_lock(&inode->i_lock);
 	list_for_each(p, &inode->i_dentry) {
-		dentry = list_entry(p, struct dentry, d_alias);
+		dentry = list_entry(p, struct dentry, d_u.d_alias);
 
 		spin_lock(&dentry->d_lock);
 		if (ocfs2_match_dentry(dentry, parent_blkno, skip_unhashed)) {

include/linux/dcache.h

@@ -133,15 +133,15 @@ struct dentry {
 	void *d_fsdata;			/* fs-specific data */
 
 	struct list_head d_lru;		/* LRU list */
+	struct list_head d_child;	/* child of parent list */
+	struct list_head d_subdirs;	/* our children */
 	/*
-	 * d_child and d_rcu can share memory
+	 * d_alias and d_rcu can share memory
 	 */
 	union {
-		struct list_head d_child;	/* child of parent list */
+		struct list_head d_alias;	/* inode alias list */
 	 	struct rcu_head d_rcu;
 	} d_u;
-	struct list_head d_subdirs;	/* our children */
-	struct list_head d_alias;	/* inode alias list */
 };
 
 /*

kernel/cgroup.c

@@ -881,7 +881,7 @@ static void cgroup_clear_directory(struct dentry *dentry)
 	spin_lock(&dentry->d_lock);
 	node = dentry->d_subdirs.next;
 	while (node != &dentry->d_subdirs) {
-		struct dentry *d = list_entry(node, struct dentry, d_u.d_child);
+		struct dentry *d = list_entry(node, struct dentry, d_child);
 
 		spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED);
 		list_del_init(node);
@@ -915,7 +915,7 @@ static void cgroup_d_remove_dir(struct dentry *dentry)
 	parent = dentry->d_parent;
 	spin_lock(&parent->d_lock);
 	spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
-	list_del_init(&dentry->d_u.d_child);
+	list_del_init(&dentry->d_child);
 	spin_unlock(&dentry->d_lock);
 	spin_unlock(&parent->d_lock);
 	remove_dir(dentry);

security/selinux/selinuxfs.c

@@ -1197,7 +1197,7 @@ static void sel_remove_entries(struct dentry *de)
 	spin_lock(&de->d_lock);
 	node = de->d_subdirs.next;
 	while (node != &de->d_subdirs) {
-		struct dentry *d = list_entry(node, struct dentry, d_u.d_child);
+		struct dentry *d = list_entry(node, struct dentry, d_child);
 
 		spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED);
 		list_del_init(node);
@@ -1704,12 +1704,12 @@ static void sel_remove_classes(void)
 
 	list_for_each(class_node, &class_dir->d_subdirs) {
 		struct dentry *class_subdir = list_entry(class_node,
-					struct dentry, d_u.d_child);
+					struct dentry, d_child);
 		struct list_head *class_subdir_node;
 
 		list_for_each(class_subdir_node, &class_subdir->d_subdirs) {
 			struct dentry *d = list_entry(class_subdir_node,
-						struct dentry, d_u.d_child);
+						struct dentry, d_child);
 
 			if (d->d_inode)
 				if (d->d_inode->i_mode & S_IFDIR)