1 files changed, 34 insertions, 26 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index 85c9e2bff8e6..8086636bf796 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -218,7 +218,7 @@ 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));
+	WARN_ON(!hlist_unhashed(&dentry->d_alias));
 	if (dname_external(dentry))
 		kfree(dentry->d_name.name);
 	kmem_cache_free(dentry_cache, dentry); 
@@ -267,7 +267,7 @@ 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);
+		hlist_del_init(&dentry->d_alias);
 		spin_unlock(&dentry->d_lock);
 		spin_unlock(&inode->i_lock);
 		if (!inode->i_nlink)
@@ -291,7 +291,7 @@ static void dentry_unlink_inode(struct dentry * dentry)
 {
 	struct inode *inode = dentry->d_inode;
 	dentry->d_inode = NULL;
-	list_del_init(&dentry->d_alias);
+	hlist_del_init(&dentry->d_alias);
 	dentry_rcuwalk_barrier(dentry);
 	spin_unlock(&dentry->d_lock);
 	spin_unlock(&inode->i_lock);
@@ -683,6 +683,8 @@ EXPORT_SYMBOL(dget_parent);
 /**
  * d_find_alias - grab a hashed alias of inode
  * @inode: inode in question
+ * @want_discon:  flag, used by d_splice_alias, to request
+ *          that only a DISCONNECTED alias be returned.
  *
  * If inode has a hashed alias, or is a directory and has any alias,
  * acquire the reference to alias and return it. Otherwise return NULL.
@@ -691,21 +693,23 @@ EXPORT_SYMBOL(dget_parent);
  * of a filesystem.
  *
  * If the inode has an IS_ROOT, DCACHE_DISCONNECTED alias, then prefer
- * any other hashed alias over that.
+ * any other hashed alias over that one unless @want_discon is set,
+ * in which case only return an IS_ROOT, DCACHE_DISCONNECTED alias.
  */
-static struct dentry *__d_find_alias(struct inode *inode)
+static struct dentry *__d_find_alias(struct inode *inode, int want_discon)
 {
 	struct dentry *alias, *discon_alias;
+	struct hlist_node *p;
 
 again:
 	discon_alias = NULL;
-	list_for_each_entry(alias, &inode->i_dentry, d_alias) {
+	hlist_for_each_entry(alias, p, &inode->i_dentry, d_alias) {
 		spin_lock(&alias->d_lock);
  		if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) {
 			if (IS_ROOT(alias) &&
 			    (alias->d_flags & DCACHE_DISCONNECTED)) {
 				discon_alias = alias;
-			} else {
+			} else if (!want_discon) {
 				__dget_dlock(alias);
 				spin_unlock(&alias->d_lock);
 				return alias;
@@ -734,9 +738,9 @@ struct dentry *d_find_alias(struct inode *inode)
 {
 	struct dentry *de = NULL;
 
-	if (!list_empty(&inode->i_dentry)) {
+	if (!hlist_empty(&inode->i_dentry)) {
 		spin_lock(&inode->i_lock);
-		de = __d_find_alias(inode);
+		de = __d_find_alias(inode, 0);
 		spin_unlock(&inode->i_lock);
 	}
 	return de;
@@ -750,9 +754,10 @@ EXPORT_SYMBOL(d_find_alias);
 void d_prune_aliases(struct inode *inode)
 {
 	struct dentry *dentry;
+	struct hlist_node *p;
 restart:
 	spin_lock(&inode->i_lock);
-	list_for_each_entry(dentry, &inode->i_dentry, d_alias) {
+	hlist_for_each_entry(dentry, p, &inode->i_dentry, d_alias) {
 		spin_lock(&dentry->d_lock);
 		if (!dentry->d_count) {
 			__dget_dlock(dentry);
@@ -974,7 +979,7 @@ static void shrink_dcache_for_umount_subtree(struct dentry *dentry)
 			inode = dentry->d_inode;
 			if (inode) {
 				dentry->d_inode = NULL;
-				list_del_init(&dentry->d_alias);
+				hlist_del_init(&dentry->d_alias);
 				if (dentry->d_op && dentry->d_op->d_iput)
 					dentry->d_op->d_iput(dentry, inode);
 				else
@@ -1309,7 +1314,7 @@ 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_HLIST_NODE(&dentry->d_alias);
 	INIT_LIST_HEAD(&dentry->d_u.d_child);
 	d_set_d_op(dentry, dentry->d_sb->s_d_op);
 
@@ -1397,7 +1402,7 @@ 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);
+		hlist_add_head(&dentry->d_alias, &inode->i_dentry);
 	}
 	dentry->d_inode = inode;
 	dentry_rcuwalk_barrier(dentry);
@@ -1422,7 +1427,7 @@ 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(!hlist_unhashed(&entry->d_alias));
 	if (inode)
 		spin_lock(&inode->i_lock);
 	__d_instantiate(entry, inode);
@@ -1455,13 +1460,14 @@ static struct dentry *__d_instantiate_unique(struct dentry *entry,
 	int len = entry->d_name.len;
 	const char *name = entry->d_name.name;
 	unsigned int hash = entry->d_name.hash;
+	struct hlist_node *p;
 
 	if (!inode) {
 		__d_instantiate(entry, NULL);
 		return NULL;
 	}
 
-	list_for_each_entry(alias, &inode->i_dentry, d_alias) {
+	hlist_for_each_entry(alias, p, &inode->i_dentry, d_alias) {
 		/*
 		 * Don't need alias->d_lock here, because aliases with
 		 * d_parent == entry->d_parent are not subject to name or
@@ -1487,7 +1493,7 @@ struct dentry *d_instantiate_unique(struct dentry *entry, struct inode *inode)
 {
 	struct dentry *result;
 
-	BUG_ON(!list_empty(&entry->d_alias));
+	BUG_ON(!hlist_unhashed(&entry->d_alias));
 
 	if (inode)
 		spin_lock(&inode->i_lock);
@@ -1528,9 +1534,9 @@ static struct dentry * __d_find_any_alias(struct inode *inode)
 {
 	struct dentry *alias;
 
-	if (list_empty(&inode->i_dentry))
+	if (hlist_empty(&inode->i_dentry))
 		return NULL;
-	alias = list_first_entry(&inode->i_dentry, struct dentry, d_alias);
+	alias = hlist_entry(inode->i_dentry.first, struct dentry, d_alias);
 	__dget(alias);
 	return alias;
 }
@@ -1604,7 +1610,7 @@ 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);
+	hlist_add_head(&tmp->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);
@@ -1647,8 +1653,9 @@ struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry)
 
 	if (inode && S_ISDIR(inode->i_mode)) {
 		spin_lock(&inode->i_lock);
-		new = __d_find_any_alias(inode);
+		new = __d_find_alias(inode, 1);
 		if (new) {
+			BUG_ON(!(new->d_flags & DCACHE_DISCONNECTED));
 			spin_unlock(&inode->i_lock);
 			security_d_instantiate(new, inode);
 			d_move(new, dentry);
@@ -2380,14 +2387,13 @@ static struct dentry *__d_unalias(struct inode *inode,
 		struct dentry *dentry, struct dentry *alias)
 {
 	struct mutex *m1 = NULL, *m2 = NULL;
-	struct dentry *ret;
+	struct dentry *ret = ERR_PTR(-EBUSY);
 
 	/* If alias and dentry share a parent, then no extra locks required */
 	if (alias->d_parent == dentry->d_parent)
 		goto out_unalias;
 
 	/* See lock_rename() */
-	ret = ERR_PTR(-EBUSY);
 	if (!mutex_trylock(&dentry->d_sb->s_vfs_rename_mutex))
 		goto out_err;
 	m1 = &dentry->d_sb->s_vfs_rename_mutex;
@@ -2395,8 +2401,10 @@ static struct dentry *__d_unalias(struct inode *inode,
 		goto out_err;
 	m2 = &alias->d_parent->d_inode->i_mutex;
 out_unalias:
-	__d_move(alias, dentry);
-	ret = alias;
+	if (likely(!d_mountpoint(alias))) {
+		__d_move(alias, dentry);
+		ret = alias;
+	}
 out_err:
 	spin_unlock(&inode->i_lock);
 	if (m2)
@@ -2478,7 +2486,7 @@ struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode)
 		struct dentry *alias;
 
 		/* Does an aliased dentry already exist? */
-		alias = __d_find_alias(inode);
+		alias = __d_find_alias(inode, 0);
 		if (alias) {
 			actual = alias;
 			write_seqlock(&rename_lock);
@@ -2618,7 +2626,7 @@ global_root:
 	if (!slash)
 		error = prepend(buffer, buflen, "/", 1);
 	if (!error)
-		error = real_mount(vfsmnt)->mnt_ns ? 1 : 2;
+		error = is_mounted(vfsmnt) ? 1 : 2;
 	goto out;
 }