Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751628AbdGZNIa (ORCPT ); Wed, 26 Jul 2017 09:08:30 -0400 Received: from mail-ua0-f195.google.com ([209.85.217.195]:34824 "EHLO mail-ua0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751582AbdGZNI2 (ORCPT ); Wed, 26 Jul 2017 09:08:28 -0400 MIME-Version: 1.0 In-Reply-To: <20170725145042.26219-3-jlayton@kernel.org> References: <20170725145042.26219-1-jlayton@kernel.org> <20170725145042.26219-3-jlayton@kernel.org> From: "Yan, Zheng" Date: Wed, 26 Jul 2017 21:08:26 +0800 Message-ID: Subject: Re: [PATCH 2/2] ceph: pagecache writeback fault injection switch To: Jeff Layton Cc: "Yan, Zheng" , Sage Weil , Ilya Dryomov , ceph-devel , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3556 Lines: 106 On Tue, Jul 25, 2017 at 10:50 PM, Jeff Layton wrote: > From: Jeff Layton > > Testing ceph for proper writeback error handling turns out to be quite > difficult. I tried using iptables to block traffic but that didn't > give reliable results. > > I hacked in this wb_fault switch that makes the filesystem pretend that > writeback failed, even when it succeeds. With this, I could verify that > cephfs fsync error reporting does work properly. > > Signed-off-by: Jeff Layton > --- > fs/ceph/addr.c | 7 +++++++ > fs/ceph/debugfs.c | 8 +++++++- > fs/ceph/super.h | 2 ++ > 3 files changed, 16 insertions(+), 1 deletion(-) > > diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c > index 50836280a6f8..a3831d100e16 100644 > --- a/fs/ceph/addr.c > +++ b/fs/ceph/addr.c > @@ -584,6 +584,10 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc) > page_off, len, > truncate_seq, truncate_size, > &inode->i_mtime, &page, 1); > + > + if (fsc->wb_fault && err >= 0) > + err = -EIO; > + > if (err < 0) { > struct writeback_control tmp_wbc; > if (!wbc) > @@ -666,6 +670,9 @@ static void writepages_finish(struct ceph_osd_request *req) > struct ceph_fs_client *fsc = ceph_inode_to_client(inode); > bool remove_page; > > + if (fsc->wb_fault && rc >= 0) > + rc = -EIO; > + > dout("writepages_finish %p rc %d\n", inode, rc); > if (rc < 0) { > mapping_set_error(mapping, rc); > diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c > index 4e2d112c982f..e1e6eaa12031 100644 > --- a/fs/ceph/debugfs.c > +++ b/fs/ceph/debugfs.c > @@ -197,7 +197,6 @@ CEPH_DEFINE_SHOW_FUNC(caps_show) > CEPH_DEFINE_SHOW_FUNC(dentry_lru_show) > CEPH_DEFINE_SHOW_FUNC(mds_sessions_show) > > - > /* > * debugfs > */ > @@ -231,6 +230,7 @@ void ceph_fs_debugfs_cleanup(struct ceph_fs_client *fsc) > debugfs_remove(fsc->debugfs_caps); > debugfs_remove(fsc->debugfs_mdsc); > debugfs_remove(fsc->debugfs_dentry_lru); > + debugfs_remove(fsc->debugfs_wb_fault); > } > > int ceph_fs_debugfs_init(struct ceph_fs_client *fsc) > @@ -298,6 +298,12 @@ int ceph_fs_debugfs_init(struct ceph_fs_client *fsc) > if (!fsc->debugfs_dentry_lru) > goto out; > > + fsc->debugfs_wb_fault = debugfs_create_bool("wb_fault", > + 0600, fsc->client->debugfs_dir, > + &fsc->wb_fault); > + if (!fsc->debugfs_wb_fault) > + goto out; > + > return 0; > > out: > diff --git a/fs/ceph/super.h b/fs/ceph/super.h > index f02a2225fe42..a38fd6203b77 100644 > --- a/fs/ceph/super.h > +++ b/fs/ceph/super.h > @@ -84,6 +84,7 @@ struct ceph_fs_client { > > unsigned long mount_state; > int min_caps; /* min caps i added */ > + bool wb_fault; > > struct ceph_mds_client *mdsc; > > @@ -100,6 +101,7 @@ struct ceph_fs_client { > struct dentry *debugfs_bdi; > struct dentry *debugfs_mdsc, *debugfs_mdsmap; > struct dentry *debugfs_mds_sessions; > + struct dentry *debugfs_wb_fault; > #endif > I think it's better not to enable this feature by default. Enabling it by compilation option or mount option? Regards Yan, Zheng > #ifdef CONFIG_CEPH_FSCACHE > -- > 2.13.3 >