On Mon, 2020-01-13 at 17:17 +0800, Yan, Zheng wrote:
> On 1/11/20 4:56 AM, Jeff Layton wrote:
> > In order to issue an async create request, we need to send an inode
> > number when we do the request, but we don't know which to which MDS
> > we'll be issuing the request.
> >
>
> the request should be sent to auth mds (dir_ci->i_auth_cap->session) of
> directory. I think grabing inode number in get_caps_for_async_create()
> is simpler.
>
That would definitely be simpler. I didn't know whether we could count
on having an i_auth_cap in that case.
Will a non-auth MDS ever hand out DIR_CREATE/DIR_UNLINK caps? I'm a
little fuzzy on what the rules are for caps being handed out by non-auth
MDS's.
> > Add a new r_req_flag that tells the request sending machinery to
> > grab an inode number from the delegated set, and encode it into the
> > request. If it can't get one then have it return -ECHILD. The
> > requestor can then reissue a synchronous request.
> >
> > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> > ---
> > fs/ceph/inode.c | 1 +
> > fs/ceph/mds_client.c | 19 ++++++++++++++++++-
> > fs/ceph/mds_client.h | 2 ++
> > 3 files changed, 21 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
> > index 79bb1e6af090..9cfc093fd273 100644
> > --- a/fs/ceph/inode.c
> > +++ b/fs/ceph/inode.c
> > @@ -1317,6 +1317,7 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req)
> > err = ceph_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_DELEG_INO, &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 852c46550d96..9e7492b21b50 100644
> > --- a/fs/ceph/mds_client.c
> > +++ b/fs/ceph/mds_client.c
> > @@ -2623,7 +2623,10 @@ static int __prepare_send_request(struct ceph_mds_client *mdsc,
> > rhead->flags = cpu_to_le32(flags);
> > rhead->num_fwd = req->r_num_fwd;
> > rhead->num_retry = req->r_attempts - 1;
> > - rhead->ino = 0;
> > + if (test_bit(CEPH_MDS_R_DELEG_INO, &req->r_req_flags))
> > + rhead->ino = cpu_to_le64(req->r_deleg_ino);
> > + else
> > + rhead->ino = 0;
> >
> > dout(" r_parent = %p\n", req->r_parent);
> > return 0;
> > @@ -2736,6 +2739,20 @@ static void __do_request(struct ceph_mds_client *mdsc,
> > goto out_session;
> > }
> >
> > + if (test_bit(CEPH_MDS_R_DELEG_INO, &req->r_req_flags) &&
> > + !req->r_deleg_ino) {
> > + req->r_deleg_ino = get_delegated_ino(req->r_session);
> > +
> > + if (!req->r_deleg_ino) {
> > + /*
> > + * If we can't get a deleg ino, exit with -ECHILD,
> > + * so the caller can reissue a sync request
> > + */
> > + err = -ECHILD;
> > + goto out_session;
> > + }
> > + }
> > +
> > /* send request */
> > req->r_resend_mds = -1; /* forget any previous mds hint */
> >
> > diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
> > index 3db7ef47e1c9..e0b36be7c44f 100644
> > --- a/fs/ceph/mds_client.h
> > +++ b/fs/ceph/mds_client.h
> > @@ -258,6 +258,7 @@ struct ceph_mds_request {
> > #define CEPH_MDS_R_GOT_RESULT (5) /* got a result */
> > #define CEPH_MDS_R_DID_PREPOPULATE (6) /* prepopulated readdir */
> > #define CEPH_MDS_R_PARENT_LOCKED (7) /* is r_parent->i_rwsem wlocked? */
> > +#define CEPH_MDS_R_DELEG_INO (8) /* attempt to get r_deleg_ino */
> > unsigned long r_req_flags;
> >
> > struct mutex r_fill_mutex;
> > @@ -307,6 +308,7 @@ struct ceph_mds_request {
> > int r_num_fwd; /* number of forward attempts */
> > int r_resend_mds; /* mds to resend to next, if any*/
> > u32 r_sent_on_mseq; /* cap mseq request was sent at*/
> > + unsigned long r_deleg_ino;
> >
> > struct list_head r_wait;
> > struct completion r_completion;
> >
--
Jeff Layton <jlayton@xxxxxxxxxx>
