[PATCH 5.4 307/344] ceph: check availability of mds cluster on mount after wait timeout

Greg Kroah-Hartman
2020-02-21T08:14:35Z

From: Xiubo Li <xiubli@redhat.com>

[ Upstream commit 97820058fb2831a4b203981fa2566ceaaa396103 ]

If all the MDS daemons are down for some reason, then the first mount
attempt will fail with EIO after the mount request times out. A mount
attempt will also fail with EIO if all of the MDS's are laggy.

This patch changes the code to return -EHOSTUNREACH in these situations
and adds a pr_info error message to help the admin determine the cause.

URL: https://tracker.ceph.com/issues/4386
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/ceph/mds_client.c | 3 +--
fs/ceph/super.c | 5 +++++
2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index ee02a742fff57..8c1f04c3a684c 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -2552,8 +2552,7 @@ static void __do_request(struct ceph_mds_client *mdsc,
if (!(mdsc->fsc->mount_options->flags &
CEPH_MOUNT_OPT_MOUNTWAIT) &&
!ceph_mdsmap_is_cluster_available(mdsc->mdsmap)) {
- err = -ENOENT;
- pr_info("probably no mds server is up\n");
+ err = -EHOSTUNREACH;
goto finish;
}
}
diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index b47f43fc2d688..62fc7d46032e8 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -1137,6 +1137,11 @@ static struct dentry *ceph_mount(struct file_system_type *fs_type,
return res;

out_splat:
+ if (!ceph_mdsmap_is_cluster_available(fsc->mdsc->mdsmap)) {
+ pr_info("No mds server is up or the cluster is laggy\n");
+ err = -EHOSTUNREACH;
+ }
+
ceph_mdsc_close_sessions(fsc->mdsc);
deactivate_locked_super(sb);
goto out_final;
--
2.20.1