1 files changed, 29 insertions, 16 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 48880fc38d1b..b5abf456c5f4 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4128,7 +4128,8 @@ EXPORT_SYMBOL(kern_path_create);
 
 void done_path_create(struct path *path, struct dentry *dentry)
 {
-	dput(dentry);
+	if (!IS_ERR(dentry))
+		dput(dentry);
 	inode_unlock(path->dentry->d_inode);
 	mnt_drop_write(path->mnt);
 	path_put(path);
@@ -4274,7 +4275,7 @@ SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, d
 }
 
 /**
- * vfs_mkdir - create directory
+ * vfs_mkdir - create directory returning correct dentry if possible
  * @idmap:	idmap of the mount the inode was found from
  * @dir:	inode of the parent directory
  * @dentry:	dentry of the child directory
@@ -4287,9 +4288,15 @@ SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, d
  * care to map the inode according to @idmap before checking permissions.
  * On non-idmapped mounts or if permission checking is to be performed on the
  * raw inode simply pass @nop_mnt_idmap.
+ *
+ * In the event that the filesystem does not use the *@dentry but leaves it
+ * negative or unhashes it and possibly splices a different one returning it,
+ * the original dentry is dput() and the alternate is returned.
+ *
+ * In case of an error the dentry is dput() and an ERR_PTR() is returned.
  */
-int vfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
-	      struct dentry *dentry, umode_t mode)
+struct dentry *vfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
+			 struct dentry *dentry, umode_t mode)
 {
 	int error;
 	unsigned max_links = dir->i_sb->s_max_links;
@@ -4297,31 +4304,35 @@ int vfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 
 	error = may_create(idmap, dir, dentry);
 	if (error)
-		return error;
+		goto err;
 
+	error = -EPERM;
 	if (!dir->i_op->mkdir)
-		return -EPERM;
+		goto err;
 
 	mode = vfs_prepare_mode(idmap, dir, mode, S_IRWXUGO | S_ISVTX, 0);
 	error = security_inode_mkdir(dir, dentry, mode);
 	if (error)
-		return error;
+		goto err;
 
+	error = -EMLINK;
 	if (max_links && dir->i_nlink >= max_links)
-		return -EMLINK;
+		goto err;
 
 	de = dir->i_op->mkdir(idmap, dir, dentry, mode);
+	error = PTR_ERR(de);
 	if (IS_ERR(de))
-		return PTR_ERR(de);
+		goto err;
 	if (de) {
-		fsnotify_mkdir(dir, de);
-		/* Cannot return de yet */
-		dput(de);
-	} else {
-		fsnotify_mkdir(dir, dentry);
+		dput(dentry);
+		dentry = de;
 	}
+	fsnotify_mkdir(dir, dentry);
+	return dentry;
 
-	return 0;
+err:
+	dput(dentry);
+	return ERR_PTR(error);
 }
 EXPORT_SYMBOL(vfs_mkdir);
 
@@ -4341,8 +4352,10 @@ retry:
 	error = security_path_mkdir(&path, dentry,
 			mode_strip_umask(path.dentry->d_inode, mode));
 	if (!error) {
-		error = vfs_mkdir(mnt_idmap(path.mnt), path.dentry->d_inode,
+		dentry = vfs_mkdir(mnt_idmap(path.mnt), path.dentry->d_inode,
 				  dentry, mode);
+		if (IS_ERR(dentry))
+			error = PTR_ERR(dentry);
 	}
 	done_path_create(&path, dentry);
 	if (retry_estale(error, lookup_flags)) {