LU-10776 osc: Do not request more than 2GiB grant

The server enforces a grant limit of 2 GiB, which the
client must honor.  The existing client code combined with
16 MiB RPCs make it possible for the client to ask for
more than this limit.

Make this limit explicit, and also fix an overflow bug in
o_undirty calculation in osc_announce_cached.  (o_undirty
is a 32 bit value and 16 MiB*256 rpcs_in_flight = 4 GiB.
4 GiB + extra grant components overflows o_undirty.)

Cray-bug-id: LUS-5750
Signed-off-by: Patrick Farrell <paf@cray.com>
Change-Id: Ifcb8a9ea7529eae4cd209dc72223ed039c6f6a0d
Reviewed-on: https://review.whamcloud.com/31533
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Reviewed-by: Bobi Jam <bobijam@hotmail.com>
Reviewed-by: Andrew Perepechko <c17827@cray.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-on: https://review.whamcloud.com/34051
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>

diff --git a/lustre/include/lustre/lustre_idl.h b/lustre/include/lustre/lustre_idl.h
index ba3ea45..f2c850c 100644 (file)
--- a/lustre/include/lustre/lustre_idl.h
+++ b/lustre/include/lustre/lustre_idl.h
@@ -1271,6 +1271,8 @@ struct hsm_state_set {
 
 #define OBD_BRW_LOCALS (OBD_BRW_LOCAL1)
 
+#define OBD_MAX_GRANT 0x7fffffffUL /* Max grant allowed to one client: 2 GiB */
+
 #define OBD_OBJECT_EOF LUSTRE_EOF
 
 #define OST_MIN_PRECREATE 32

diff --git a/lustre/osc/osc_request.c b/lustre/osc/osc_request.c
index e78c242..5b7e2c9 100644 (file)
--- a/lustre/osc/osc_request.c
+++ b/lustre/osc/osc_request.c
@@ -697,11 +697,12 @@ static void osc_announce_cached(struct client_obd *cli, struct obdo *oa,
                oa->o_undirty = 0;
        } else {
                unsigned long nrpages;
+               unsigned long undirty;
 
                nrpages = cli->cl_max_pages_per_rpc;
                nrpages *= cli->cl_max_rpcs_in_flight + 1;
                nrpages = max(nrpages, cli->cl_dirty_max_pages);
-               oa->o_undirty = nrpages << PAGE_SHIFT;
+               undirty = nrpages << PAGE_SHIFT;
                if (OCD_HAS_FLAG(&cli->cl_import->imp_connect_data,
                                 GRANT_PARAM)) {
                        int nrextents;
@@ -710,8 +711,13 @@ static void osc_announce_cached(struct client_obd *cli, struct obdo *oa,
                         * grant space */
                        nrextents = (nrpages + cli->cl_max_extent_pages - 1)  /
                                     cli->cl_max_extent_pages;
-                       oa->o_undirty += nrextents * cli->cl_grant_extent_tax;
+                       undirty += nrextents * cli->cl_grant_extent_tax;
                }
+               /* Do not ask for more than OBD_MAX_GRANT - a margin for server
+                * to add extent tax, etc.
+                */
+               oa->o_undirty = min(undirty, OBD_MAX_GRANT -
+                                   (PTLRPC_MAX_BRW_PAGES << PAGE_SHIFT)*4UL);
         }
        oa->o_grant = cli->cl_avail_grant + cli->cl_reserved_grant;
         oa->o_dropped = cli->cl_lost_grant;

diff --git a/lustre/target/tgt_grant.c b/lustre/target/tgt_grant.c
index b13db06..bedf54e 100644 (file)
--- a/lustre/target/tgt_grant.c
+++ b/lustre/target/tgt_grant.c
@@ -890,9 +890,10 @@ static long tgt_grant_alloc(struct obd_export *exp, u64 curgrant,
             tgd->tgd_grant_compat_disable) || left == 0 || exp->exp_failed)
                RETURN(0);
 
-       if (want > 0x7fffffff) {
-               CERROR("%s: client %s/%p requesting > 2GB grant %llu\n",
-                      obd->obd_name, exp->exp_client_uuid.uuid, exp, want);
+       if (want > OBD_MAX_GRANT) {
+               CERROR("%s: client %s/%p requesting > max (%lu), %llu\n",
+                      obd->obd_name, exp->exp_client_uuid.uuid, exp,
+                      OBD_MAX_GRANT, want);
                RETURN(0);
        }