From patchwork Mon May 18 17:47:26 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 11555977 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B223F912 for ; Mon, 18 May 2020 17:47:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 99D8920835 for ; Mon, 18 May 2020 17:47:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730234AbgERRrf (ORCPT ); Mon, 18 May 2020 13:47:35 -0400 Received: from mx2.suse.de ([195.135.220.15]:53750 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729715AbgERRra (ORCPT ); Mon, 18 May 2020 13:47:30 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 027DCACE6; Mon, 18 May 2020 17:47:30 +0000 (UTC) Received: from localhost (webern.olymp [local]) by webern.olymp (OpenSMTPD) with ESMTPA id 1911f9ee; Mon, 18 May 2020 18:47:26 +0100 (WEST) Date: Mon, 18 May 2020 18:47:26 +0100 From: Luis Henriques To: Jeff Layton , Amir Goldstein , Ilya Dryomov Cc: ceph-devel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] ceph: don't return -ESTALE if there's still an open file Message-ID: <20200518174726.GA84496@suse.com> MIME-Version: 1.0 Content-Disposition: inline Sender: ceph-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org Similarly to commit 03f219041fdb ("ceph: check i_nlink while converting a file handle to dentry"), this fixes another corner case with name_to_handle_at/open_by_handle_at. The issue has been detected by xfstest generic/467, when doing: - name_to_handle_at("/cephfs/myfile") - open("/cephfs/myfile") - unlink("/cephfs/myfile") - sync; sync; - drop caches - open_by_handle_at() The call to open_by_handle_at should not fail because the file hasn't been deleted yet (only unlinked) and we do have a valid handle to it. -ESTALE shall be returned only if i_nlink is 0 *and* i_count is 1. This patch also makes sure we have LINK caps before checking i_nlink. Signed-off-by: Luis Henriques Acked-by: Amir Goldstein --- Hi! (and sorry for the delay in my reply!) So, from the discussion thread and some IRC chat with Jeff, I'm sending v2. What changed? Everything! :-) - Use i_count instead of __ceph_is_file_opened to check for open files - Add call to ceph_do_getattr to make sure we have LINK caps before accessing i_nlink Cheers, -- Luis fs/ceph/export.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/fs/ceph/export.c b/fs/ceph/export.c index 79dc06881e78..e088843a7734 100644 --- a/fs/ceph/export.c +++ b/fs/ceph/export.c @@ -172,9 +172,16 @@ struct inode *ceph_lookup_inode(struct super_block *sb, u64 ino) static struct dentry *__fh_to_dentry(struct super_block *sb, u64 ino) { struct inode *inode = __lookup_inode(sb, ino); + int err; + if (IS_ERR(inode)) return ERR_CAST(inode); - if (inode->i_nlink == 0) { + /* We need LINK caps to reliably check i_nlink */ + err = ceph_do_getattr(inode, CEPH_CAP_LINK_SHARED, false); + if (err) + return ERR_PTR(err); + /* -ESTALE if inode as been unlinked and no file is open */ + if ((inode->i_nlink == 0) && (atomic_read(&inode->i_count) == 1)) { iput(inode); return ERR_PTR(-ESTALE); }