ceph: add flag to designate that a request is asynchronous
...and ensure that such requests are never queued. The MDS has need to
know that a request is asynchronous so add flags and proper
infrastructure for that.
Also, delegated inode numbers and directory caps are associated with the
session, so ensure that async requests are always transmitted on the
first attempt and are never queued to wait for session reestablishment.
If it does end up looking like we'll need to queue the request, then
have it return -EJUKEBOX so the caller can reattempt with a synchronous
request.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 2da98b6..9e8b209 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -2528,6 +2528,8 @@ static int __prepare_send_request(struct ceph_mds_client *mdsc,
rhead->oldest_client_tid = cpu_to_le64(__get_oldest_tid(mdsc));
if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags))
flags |= CEPH_MDS_FLAG_REPLAY;
+ if (test_bit(CEPH_MDS_R_ASYNC, &req->r_req_flags))
+ flags |= CEPH_MDS_FLAG_ASYNC;
if (req->r_parent)
flags |= CEPH_MDS_FLAG_WANT_DENTRY;
rhead->flags = cpu_to_le32(flags);
@@ -2611,6 +2613,10 @@ static void __do_request(struct ceph_mds_client *mdsc,
mds = __choose_mds(mdsc, req, &random);
if (mds < 0 ||
ceph_mdsmap_get_state(mdsc->mdsmap, mds) < CEPH_MDS_STATE_ACTIVE) {
+ if (test_bit(CEPH_MDS_R_ASYNC, &req->r_req_flags)) {
+ err = -EJUKEBOX;
+ goto finish;
+ }
dout("do_request no mds or not active, waiting for map\n");
list_add(&req->r_wait, &mdsc->waiting_for_map);
return;
@@ -2635,6 +2641,15 @@ static void __do_request(struct ceph_mds_client *mdsc,
err = -EACCES;
goto out_session;
}
+ /*
+ * We cannot queue async requests since the caps and delegated
+ * inodes are bound to the session. Just return -EJUKEBOX and
+ * let the caller retry a sync request in that case.
+ */
+ if (test_bit(CEPH_MDS_R_ASYNC, &req->r_req_flags)) {
+ err = -EJUKEBOX;
+ goto out_session;
+ }
if (session->s_state == CEPH_MDS_SESSION_NEW ||
session->s_state == CEPH_MDS_SESSION_CLOSING) {
__open_session(mdsc, session);