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>

1 files changed, 1 insertions, 0 deletions

diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index a0918d00117c..95ac00e59e66 100644
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -255,6 +255,7 @@ 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_ASYNC		(8) /* async request */
 	unsigned long	r_req_flags;
 
 	struct mutex r_fill_mutex;