1 files changed, 49 insertions, 88 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index b212a65ed190..475ef1edba03 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -344,7 +344,7 @@ static inline void __d_set_inode_and_type(struct dentry *dentry,
 
 	dentry->d_inode = inode;
 	flags = READ_ONCE(dentry->d_flags);
-	flags &= ~(DCACHE_ENTRY_TYPE | DCACHE_FALLTHRU);
+	flags &= ~DCACHE_ENTRY_TYPE;
 	flags |= type_flags;
 	smp_store_release(&dentry->d_flags, flags);
 }
@@ -353,7 +353,7 @@ static inline void __d_clear_type_and_inode(struct dentry *dentry)
 {
 	unsigned flags = READ_ONCE(dentry->d_flags);
 
-	flags &= ~(DCACHE_ENTRY_TYPE | DCACHE_FALLTHRU);
+	flags &= ~DCACHE_ENTRY_TYPE;
 	WRITE_ONCE(dentry->d_flags, flags);
 	dentry->d_inode = NULL;
 	if (dentry->d_flags & DCACHE_LRU_LIST)
@@ -885,11 +885,6 @@ static inline void __dget_dlock(struct dentry *dentry)
 	dentry->d_lockref.count++;
 }
 
-static inline void __dget(struct dentry *dentry)
-{
-	lockref_get(&dentry->d_lockref);
-}
-
 struct dentry *dget_parent(struct dentry *dentry)
 {
 	int gotref;
@@ -939,7 +934,7 @@ static struct dentry * __d_find_any_alias(struct inode *inode)
 	if (hlist_empty(&inode->i_dentry))
 		return NULL;
 	alias = hlist_entry(inode->i_dentry.first, struct dentry, d_u.d_alias);
-	__dget(alias);
+	lockref_get(&alias->d_lockref);
 	return alias;
 }
 
@@ -1764,9 +1759,15 @@ struct dentry *d_alloc_cursor(struct dentry * parent)
  */
 struct dentry *d_alloc_pseudo(struct super_block *sb, const struct qstr *name)
 {
+	static const struct dentry_operations anon_ops = {
+		.d_dname = simple_dname
+	};
 	struct dentry *dentry = __d_alloc(sb, name);
-	if (likely(dentry))
+	if (likely(dentry)) {
 		dentry->d_flags |= DCACHE_NORCU;
+		if (!sb->s_d_op)
+			d_set_d_op(dentry, &anon_ops);
+	}
 	return dentry;
 }
 
@@ -1810,22 +1811,6 @@ void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op)
 }
 EXPORT_SYMBOL(d_set_d_op);
 
-
-/*
- * d_set_fallthru - Mark a dentry as falling through to a lower layer
- * @dentry - The dentry to mark
- *
- * Mark a dentry as falling through to the lower layer (as set with
- * d_pin_lower()).  This flag may be recorded on the medium.
- */
-void d_set_fallthru(struct dentry *dentry)
-{
-	spin_lock(&dentry->d_lock);
-	dentry->d_flags |= DCACHE_FALLTHRU;
-	spin_unlock(&dentry->d_lock);
-}
-EXPORT_SYMBOL(d_set_fallthru);
-
 static unsigned d_flags_for_inode(struct inode *inode)
 {
 	unsigned add_flags = DCACHE_REGULAR_TYPE;
@@ -1944,75 +1929,55 @@ struct dentry *d_make_root(struct inode *root_inode)
 }
 EXPORT_SYMBOL(d_make_root);
 
-static struct dentry *__d_instantiate_anon(struct dentry *dentry,
-					   struct inode *inode,
-					   bool disconnected)
-{
-	struct dentry *res;
-	unsigned add_flags;
-
-	security_d_instantiate(dentry, inode);
-	spin_lock(&inode->i_lock);
-	res = __d_find_any_alias(inode);
-	if (res) {
-		spin_unlock(&inode->i_lock);
-		dput(dentry);
-		goto out_iput;
-	}
-
-	/* attach a disconnected dentry */
-	add_flags = d_flags_for_inode(inode);
-
-	if (disconnected)
-		add_flags |= DCACHE_DISCONNECTED;
-
-	spin_lock(&dentry->d_lock);
-	__d_set_inode_and_type(dentry, inode, add_flags);
-	hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry);
-	if (!disconnected) {
-		hlist_bl_lock(&dentry->d_sb->s_roots);
-		hlist_bl_add_head(&dentry->d_hash, &dentry->d_sb->s_roots);
-		hlist_bl_unlock(&dentry->d_sb->s_roots);
-	}
-	spin_unlock(&dentry->d_lock);
-	spin_unlock(&inode->i_lock);
-
-	return dentry;
-
- out_iput:
-	iput(inode);
-	return res;
-}
-
-struct dentry *d_instantiate_anon(struct dentry *dentry, struct inode *inode)
-{
-	return __d_instantiate_anon(dentry, inode, true);
-}
-EXPORT_SYMBOL(d_instantiate_anon);
-
 static struct dentry *__d_obtain_alias(struct inode *inode, bool disconnected)
 {
-	struct dentry *tmp;
-	struct dentry *res;
+	struct super_block *sb;
+	struct dentry *new, *res;
 
 	if (!inode)
 		return ERR_PTR(-ESTALE);
 	if (IS_ERR(inode))
 		return ERR_CAST(inode);
 
-	res = d_find_any_alias(inode);
+	sb = inode->i_sb;
+
+	res = d_find_any_alias(inode); /* existing alias? */
 	if (res)
-		goto out_iput;
+		goto out;
 
-	tmp = d_alloc_anon(inode->i_sb);
-	if (!tmp) {
+	new = d_alloc_anon(sb);
+	if (!new) {
 		res = ERR_PTR(-ENOMEM);
-		goto out_iput;
+		goto out;
 	}
 
-	return __d_instantiate_anon(tmp, inode, disconnected);
+	security_d_instantiate(new, inode);
+	spin_lock(&inode->i_lock);
+	res = __d_find_any_alias(inode); /* recheck under lock */
+	if (likely(!res)) { /* still no alias, attach a disconnected dentry */
+		unsigned add_flags = d_flags_for_inode(inode);
+
+		if (disconnected)
+			add_flags |= DCACHE_DISCONNECTED;
 
-out_iput:
+		spin_lock(&new->d_lock);
+		__d_set_inode_and_type(new, inode, add_flags);
+		hlist_add_head(&new->d_u.d_alias, &inode->i_dentry);
+		if (!disconnected) {
+			hlist_bl_lock(&sb->s_roots);
+			hlist_bl_add_head(&new->d_hash, &sb->s_roots);
+			hlist_bl_unlock(&sb->s_roots);
+		}
+		spin_unlock(&new->d_lock);
+		spin_unlock(&inode->i_lock);
+		inode = NULL; /* consumed by new->d_inode */
+		res = new;
+	} else {
+		spin_unlock(&inode->i_lock);
+		dput(new);
+	}
+
+ out:
 	iput(inode);
 	return res;
 }
@@ -2596,7 +2561,7 @@ retry:
 	/* we can't take ->d_lock here; it's OK, though. */
 	new->d_flags |= DCACHE_PAR_LOOKUP;
 	new->d_wait = wq;
-	hlist_bl_add_head_rcu(&new->d_u.d_in_lookup_hash, b);
+	hlist_bl_add_head(&new->d_u.d_in_lookup_hash, b);
 	hlist_bl_unlock(b);
 	return new;
 mismatch:
@@ -2953,8 +2918,7 @@ struct dentry *d_ancestor(struct dentry *p1, struct dentry *p2)
  * Note: If ever the locking in lock_rename() changes, then please
  * remember to update this too...
  */
-static int __d_unalias(struct inode *inode,
-		struct dentry *dentry, struct dentry *alias)
+static int __d_unalias(struct dentry *dentry, struct dentry *alias)
 {
 	struct mutex *m1 = NULL;
 	struct rw_semaphore *m2 = NULL;
@@ -3035,7 +2999,7 @@ struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry)
 					inode->i_sb->s_id);
 			} else if (!IS_ROOT(new)) {
 				struct dentry *old_parent = dget(new->d_parent);
-				int err = __d_unalias(inode, dentry, new);
+				int err = __d_unalias(dentry, new);
 				write_sequnlock(&rename_lock);
 				if (err) {
 					dput(new);
@@ -3106,10 +3070,7 @@ static enum d_walk_ret d_genocide_kill(void *data, struct dentry *dentry)
 		if (d_unhashed(dentry) || !dentry->d_inode)
 			return D_WALK_SKIP;
 
-		if (!(dentry->d_flags & DCACHE_GENOCIDE)) {
-			dentry->d_flags |= DCACHE_GENOCIDE;
-			dentry->d_lockref.count--;
-		}
+		dentry->d_lockref.count--;
 	}
 	return D_WALK_CONTINUE;
 }