fs: make sure to call fsnotify_inoderemove() only once when inode is dead

index 1b1a81f10da6..8f17db2724b3 100644
@@ -450,6 +450,17 @@ static void dentry_free(struct dentry *dentry)
 		call_rcu(&dentry->d_rcu, __d_free);
 }
 
+/*
+ * If inode is unlinked and doesn't have any aliases (i.e., all fds pointing to
+ * it are closed), it is pretty much dead. Except that file handle lookup could
+ * still revive it which causes issues to fsnotify. So once inode reaches this
+ * state we make sure to block creating any new aliases.
+ */
+static bool inode_notify_dead(struct inode *inode)
+{
+	return !inode->i_nlink && hlist_empty(&inode->i_dentry);
+}
+
 /*
  * Release the dentry's inode, using the filesystem
  * d_iput() operation if defined.

@@ -459,6 +470,7 @@ static void dentry_unlink_inode(struct dentry * dentry)
 	__releases(dentry->d_inode->i_lock)
 {
 	struct inode *inode = dentry->d_inode;
+	bool notify_dead;
 
 	raw_write_seqcount_begin(&dentry->d_seq);
 	__d_clear_type_and_inode(dentry);

@@ -469,9 +481,10 @@ static void dentry_unlink_inode(struct dentry * dentry)
 	 */
 	dentry->waiters = NULL;
 	raw_write_seqcount_end(&dentry->d_seq);
+	notify_dead = inode_notify_dead(inode);
 	spin_unlock(&dentry->d_lock);
 	spin_unlock(&inode->i_lock);
-	if (!inode->i_nlink)
+	if (notify_dead)
 		fsnotify_inoderemove(inode);
 	if (dentry->d_op && dentry->d_op->d_iput)
 		dentry->d_op->d_iput(dentry, inode);

@@ -2237,7 +2250,12 @@ static struct dentry *__d_obtain_alias(struct inode *inode, bool disconnected)
 
 	sb = inode->i_sb;
 
-	res = d_find_any_alias(inode); /* existing alias? */
+	spin_lock(&inode->i_lock);
+	if (!inode_notify_dead(inode))
+		res = __d_find_any_alias(inode);	/* existing alias? */
+	else
+		res = ERR_PTR(-ESTALE);
+	spin_unlock(&inode->i_lock);
 	if (res)
 		goto out;
 

@@ -2249,7 +2267,10 @@ static struct dentry *__d_obtain_alias(struct inode *inode, bool disconnected)
 
 	security_d_instantiate(new, inode);
 	spin_lock(&inode->i_lock);
-	res = __d_find_any_alias(inode); /* recheck under lock */
+	if (!inode_notify_dead(inode))
+		res = __d_find_any_alias(inode);	/* recheck under lock */
+	else
+		res = ERR_PTR(-ESTALE);
 	if (likely(!res)) { /* still no alias, attach a disconnected dentry */
 		unsigned add_flags = d_flags_for_inode(inode);