On Thu, 2020-02-13 at 17:29 +0800, Yan, Zheng wrote:
> On Thu, Feb 13, 2020 at 1:29 AM Jeff Layton <jlayton@xxxxxxxxxx> wrote:
> > ...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@xxxxxxxxxx>
> > ---
> > fs/ceph/inode.c | 1 +
> > fs/ceph/mds_client.c | 11 +++++++++++
> > fs/ceph/mds_client.h | 1 +
> > include/linux/ceph/ceph_fs.h | 5 +++--
> > 4 files changed, 16 insertions(+), 2 deletions(-)
> >
> > diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
> > index 094b8fc37787..9869ec101e88 100644
> > --- a/fs/ceph/inode.c
> > +++ b/fs/ceph/inode.c
> > @@ -1311,6 +1311,7 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req)
> > err = fill_inode(in, req->r_locked_page, &rinfo->targeti, NULL,
> > session,
> > (!test_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags) &&
> > + !test_bit(CEPH_MDS_R_ASYNC, &req->r_req_flags) &&
> > rinfo->head->result == 0) ? req->r_fmode : -1,
> > &req->r_caps_reservation);
> > if (err < 0) {
> > diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> > index 2980e57ca7b9..9f2aeb6908b2 100644
> > --- a/fs/ceph/mds_client.c
> > +++ b/fs/ceph/mds_client.c
> > @@ -2527,6 +2527,8 @@ 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);
> > @@ -2634,6 +2636,15 @@ 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;
> > + }
>
> the code near __choose_mds also can queue request
>
>
Ahh, right. Something like this maybe:
[PATCH] SQUASH: don't allow async req to be queued waiting for mdsmap
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
fs/ceph/mds_client.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 09d5301b036c..ac5bd58bb971 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -2702,6 +2702,10 @@ 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;
--
2.24.1
