From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from zeniv.linux.org.uk ([195.92.253.2]:36248 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751903AbeEMQDn (ORCPT ); Sun, 13 May 2018 12:03:43 -0400 Date: Sun, 13 May 2018 17:03:42 +0100 From: Al Viro To: linux-fsdevel@vger.kernel.org Cc: David Sterba , Fabian Frederick Subject: [RFC][PATCH] affs_lookup: switch to d_splice_alias() Message-ID: <20180513160341.GN30522@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Making something exportable takes more than providing ->s_export_ops. In particular, ->lookup() *MUST* use d_splice_alias() instead of d_add(). Reading Documentation/filesystems/nfs/Exporting would've been a good idea; as it is, exporting AFFS is badly (and exploitably) broken. Partially-Fixes: ed4433d72394 "fs/affs: make affs exportable" Signed-off-by: Al Viro diff --git a/fs/affs/namei.c b/fs/affs/namei.c index 1ed0fa4c4d48..41c5749f4db7 100644 --- a/fs/affs/namei.c +++ b/fs/affs/namei.c @@ -201,6 +201,7 @@ affs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) struct super_block *sb = dir->i_sb; struct buffer_head *bh; struct inode *inode = NULL; + struct dentry *res; pr_debug("%s(\"%pd\")\n", __func__, dentry); @@ -223,14 +224,12 @@ affs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) } affs_brelse(bh); inode = affs_iget(sb, ino); - if (IS_ERR(inode)) { - affs_unlock_dir(dir); - return ERR_CAST(inode); - } } - d_add(dentry, inode); + res = d_splice_alias(inode, dentry); + if (!IS_ERR_OR_NULL(res)) + res->d_fsdata = dentry->d_fsdata; affs_unlock_dir(dir); - return NULL; + return res; } int