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authorXiubo Li <xiubli@redhat.com>2020-05-20 03:51:19 -0400
committerIlya Dryomov <idryomov@gmail.com>2020-06-01 13:22:53 +0200
commitea8412b284c09742d5b11721e225b4ff011aa397 (patch)
tree84699cc906c8a96ca329dda380a2628fe3acd931 /fs/ceph
parent878dabb64117406abd40977b87544d05bb3031fc (diff)
downloadlinux-ea8412b284c09742d5b11721e225b4ff011aa397.tar.bz2
ceph: make sure mdsc->mutex is nested in s->s_mutex to fix dead lock
send_mds_reconnect takes the s_mutex while the mdsc->mutex is already held. That inverts the locking order documented in mds_client.h. Drop the mdsc->mutex, acquire the s_mutex and then reacquire the mdsc->mutex to prevent a deadlock. URL: https://tracker.ceph.com/issues/45609 Signed-off-by: Xiubo Li <xiubli@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Diffstat (limited to 'fs/ceph')
-rw-r--r--fs/ceph/mds_client.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 6c283c52d401..0e0ab01694dc 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -3769,8 +3769,6 @@ fail:
* recovering MDS might have.
*
* This is a relatively heavyweight operation, but it's rare.
- *
- * called with mdsc->mutex held.
*/
static void send_mds_reconnect(struct ceph_mds_client *mdsc,
struct ceph_mds_session *session)
@@ -4024,7 +4022,9 @@ static void check_new_map(struct ceph_mds_client *mdsc,
oldstate != CEPH_MDS_STATE_STARTING)
pr_info("mds%d recovery completed\n", s->s_mds);
kick_requests(mdsc, i);
+ mutex_unlock(&mdsc->mutex);
mutex_lock(&s->s_mutex);
+ mutex_lock(&mdsc->mutex);
ceph_kick_flushing_caps(mdsc, s);
mutex_unlock(&s->s_mutex);
wake_up_session_caps(s, RECONNECT);