From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b="fvIi7k46" Received: from zeniv.linux.org.uk (zeniv.linux.org.uk [IPv6:2a03:a000:7:0:5054:ff:fe1c:15ff]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 657F3127; Sat, 25 Nov 2023 12:11:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description; bh=T08sUyzdKaybfEkZCNae4ocOGsjYgJj1qnspFJtuRWw=; b=fvIi7k46RHfJK7RTy5TGozS6Ua XAdcnLEO4sw2DJk9NFpGgleDZrmOVdFvPyviE+d6EH/kn7S6fvGNbfgLJ/E+AjrJwYynr6vqADksd J9xfEMbHbnp2gEWGmlnDhmI7keINg1U/P8lyVAX/PwYPXtFS9lUafIk8HHpfMyeUk8BxfIl1q24xM 2Gg00raJtCN1PVCh4NqJm7w9Xk5hA/bmPxJuopyulFZU4a7JcbcQKMt/v0/LEfK8R/BKH3lPTUI4X 4cKgtDVX69Lq1layYaICqnkS6tTZnUkgqq8DLSxwyESGcx5C/q+gWu/axyLhZdRTAzzR1i3B4dngF 7HDkW05A==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.96 #2 (Red Hat Linux)) id 1r6z0F-003A4f-35; Sat, 25 Nov 2023 20:11:48 +0000 From: Al Viro To: linux-fsdevel@vger.kernel.org Cc: Linus Torvalds , Mo Zou , Jan Kara , linux-kernel@vger.kernel.org Subject: [PATCH v2 4/9] ext2: Avoid reading renamed directory if parent does not change Date: Sat, 25 Nov 2023 20:11:42 +0000 Message-Id: <20231125201147.753695-4-viro@zeniv.linux.org.uk> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20231125201147.753695-1-viro@zeniv.linux.org.uk> References: <20231125201015.GA38156@ZenIV> <20231125201147.753695-1-viro@zeniv.linux.org.uk> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: Al Viro From: Jan Kara The VFS will not be locking moved directory if its parent does not change. Change ext2 rename code to avoid reading renamed directory if its parent does not change. Although it is currently harmless it is a bad practice to read directory contents without inode->i_rwsem. Signed-off-by: Jan Kara Signed-off-by: Al Viro --- fs/ext2/namei.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c index 65f702b1da5b..8346ab9534c1 100644 --- a/fs/ext2/namei.c +++ b/fs/ext2/namei.c @@ -325,6 +325,7 @@ static int ext2_rename (struct mnt_idmap * idmap, struct ext2_dir_entry_2 * dir_de = NULL; struct folio * old_folio; struct ext2_dir_entry_2 * old_de; + bool old_is_dir = S_ISDIR(old_inode->i_mode); int err; if (flags & ~RENAME_NOREPLACE) @@ -342,7 +343,7 @@ static int ext2_rename (struct mnt_idmap * idmap, if (IS_ERR(old_de)) return PTR_ERR(old_de); - if (S_ISDIR(old_inode->i_mode)) { + if (old_is_dir && old_dir != new_dir) { err = -EIO; dir_de = ext2_dotdot(old_inode, &dir_folio); if (!dir_de) @@ -354,7 +355,7 @@ static int ext2_rename (struct mnt_idmap * idmap, struct ext2_dir_entry_2 *new_de; err = -ENOTEMPTY; - if (dir_de && !ext2_empty_dir (new_inode)) + if (old_is_dir && !ext2_empty_dir(new_inode)) goto out_dir; new_de = ext2_find_entry(new_dir, &new_dentry->d_name, @@ -368,14 +369,14 @@ static int ext2_rename (struct mnt_idmap * idmap, if (err) goto out_dir; inode_set_ctime_current(new_inode); - if (dir_de) + if (old_is_dir) drop_nlink(new_inode); inode_dec_link_count(new_inode); } else { err = ext2_add_link(new_dentry, old_inode); if (err) goto out_dir; - if (dir_de) + if (old_is_dir) inode_inc_link_count(new_dir); } @@ -387,7 +388,7 @@ static int ext2_rename (struct mnt_idmap * idmap, mark_inode_dirty(old_inode); err = ext2_delete_entry(old_de, old_folio); - if (!err && dir_de) { + if (!err && old_is_dir) { if (old_dir != new_dir) err = ext2_set_link(old_inode, dir_de, dir_folio, new_dir, false); -- 2.39.2