LU-7975 lod: fix delayed stripe error path & Client resend

This patch is a follow-on to LU-4260/LU-4971/LU-5346 to fix
cleanup in error path during layout/stripe creation.
It is intended to fix special case when layout creation has been
delayed and will be with a non-0 size (ie truncate).

Problem has been unveiled due to the current limitation where a
delayed layout creation with a non-0 size/truncate will not be
resent if connection with OST is down, but is rather returning
-EAGAIN/-EWOULDBLOCK upon next open, and finally MDS will crash for
"(lod_object.c:700:lod_ah_init()) ASSERTION( lc->ldo_stripenr == 0 )"
LBUG.

Thus, patch also fixes this limitation by instead returning
-EINPROGRESS,this to avoid using costly resend operation from MDS
(will keep a ptlrpc thread busy) but offload this responsibility to
Client side (in after_reply()) which will handle this process in a
much less agressive way.

Specific sanity/test_27F sub-test has been created to test both
layout creation error path correct cleanup and Client resend.

Signed-off-by: Bruno Faccini <bruno.faccini@intel.com>
Change-Id: Ibc1734f52c071c66cb5974e3fe21d8819d725c2a
Reviewed-on: http://review.whamcloud.com/19302
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>

diff --git a/lustre/lod/lod_object.c b/lustre/lod/lod_object.c
index 62e8967..165d4bd 100644 (file)
--- a/lustre/lod/lod_object.c
+++ b/lustre/lod/lod_object.c
@@ -3344,22 +3344,14 @@ int lod_declare_striped_object(const struct lu_env *env, struct dt_object *dt,
        int                      rc;
        ENTRY;
 
        int                      rc;
        ENTRY;
 

-       if (OBD_FAIL_CHECK(OBD_FAIL_MDS_ALLOC_OBDO)) {
-               /* failed to create striping, let's reset
-                * config so that others don't get confused */
-               lod_object_free_striping(env, lo);
+       if (OBD_FAIL_CHECK(OBD_FAIL_MDS_ALLOC_OBDO))

                GOTO(out, rc = -ENOMEM);
                GOTO(out, rc = -ENOMEM);

-       }

 
        if (!dt_object_remote(next)) {
                /* choose OST and generate appropriate objects */
                rc = lod_qos_prep_create(env, lo, attr, lovea, th);
 
        if (!dt_object_remote(next)) {
                /* choose OST and generate appropriate objects */
                rc = lod_qos_prep_create(env, lo, attr, lovea, th);

-               if (rc) {
-                       /* failed to create striping, let's reset
-                        * config so that others don't get confused */
-                       lod_object_free_striping(env, lo);
+               if (rc)

                        GOTO(out, rc);
                        GOTO(out, rc);

-               }

 
                /*
                 * declare storage for striping data
 
                /*
                 * declare storage for striping data


@@ -3390,6 +3382,11 @@ int lod_declare_striped_object(const struct lu_env *env, struct dt_object *dt,
                rc = lod_declare_init_size(env, dt, th);
 
 out:
                rc = lod_declare_init_size(env, dt, th);
 
 out:

+       /* failed to create striping or to set initial size, let's reset
+        * config so that others don't get confused */
+       if (rc)
+               lod_object_free_striping(env, lo);
+

        RETURN(rc);
 }
 
        RETURN(rc);
 }
 

diff --git a/lustre/osp/osp_precreate.c b/lustre/osp/osp_precreate.c
index b9f6760..d5b4022 100644 (file)
--- a/lustre/osp/osp_precreate.c
+++ b/lustre/osp/osp_precreate.c
@@ -1482,6 +1482,13 @@ int osp_object_truncate(const struct lu_env *env, struct dt_object *dt,
         * XXX: decide how do we do here with resend
         * if we don't resend, then client may see wrong file size
         * if we do resend, then MDS thread can get stuck for quite long
         * XXX: decide how do we do here with resend
         * if we don't resend, then client may see wrong file size
         * if we do resend, then MDS thread can get stuck for quite long

+        * and if we don't resend, then client will also get -EWOULDBLOCK !!
+        * (see LU-7975 and sanity/test_27F use cases)
+        * but let's decide not to resend/delay this truncate request to OST
+        * and allow Client to decide to resend, in a less agressive way from
+        * after_reply(), by returning -EINPROGRESS instead of
+        * -EAGAIN/-EWOULDBLOCK upon return from ptlrpc_queue_wait() at the
+        * end of this routine

         */
        req->rq_no_resend = req->rq_no_delay = 1;
 
         */
        req->rq_no_resend = req->rq_no_delay = 1;
 


@@ -1509,8 +1516,23 @@ int osp_object_truncate(const struct lu_env *env, struct dt_object *dt,
        ptlrpc_request_set_replen(req);
 
        rc = ptlrpc_queue_wait(req);
        ptlrpc_request_set_replen(req);
 
        rc = ptlrpc_queue_wait(req);

-       if (rc)
-               CERROR("can't punch object: %d\n", rc);
+       if (rc) {
+               /* -EWOULDBLOCK/-EAGAIN means OST is unreachable at the moment
+                * since we have decided not to resend/delay, but this could
+                * lead to wrong size to be seen at Client side and even process
+                * trying to open to exit/fail if not itself handling -EAGAIN.
+                * So it should be better to return -EINPROGRESS instead and
+                * leave the decision to resend at Client side in after_reply()
+                */
+               if (rc == -EWOULDBLOCK) {
+                       rc = -EINPROGRESS;
+                       CDEBUG(D_HA, "returning -EINPROGRESS instead of "
+                              "-EWOULDBLOCK/-EAGAIN to allow Client to "
+                              "resend\n");
+               } else {
+                       CERROR("can't punch object: %d\n", rc);
+               }
+       }

 out:
        ptlrpc_req_finished(req);
        if (oa)
 out:
        ptlrpc_req_finished(req);
        if (oa)

diff --git a/lustre/tests/sanity.sh b/lustre/tests/sanity.sh
index d9199d5..08ee3e2 100644 (file)
--- a/lustre/tests/sanity.sh
+++ b/lustre/tests/sanity.sh
@@ -2069,6 +2069,46 @@ test_27E() {
 }
 run_test 27E "check that default extended attribute size properly increases"
 
 }
 run_test 27E "check that default extended attribute size properly increases"
 

+test_27F() { # LU-5346/LU-7975
+
+       [ $PARALLEL == "yes" ] && skip "skip parallel run" && return
+
+       [[ $(lustre_version_code $SINGLEMDS) -lt $(version_code 2.8.51) ]] &&
+               skip "Need MDS version at least 2.8.51" && return
+
+       test_mkdir -p $DIR/$tdir
+       rm -f $DIR/$tdir/f0
+       $SETSTRIPE -c 2 $DIR/$tdir
+
+       # stop all OSTs to reproduce situation for LU-7975 ticket
+       for num in $(seq $OSTCOUNT); do
+               stop ost$num
+       done
+
+       # open/create f0 with O_LOV_DELAY_CREATE
+       # truncate f0 to a non-0 size
+       # close
+       multiop $DIR/$tdir/f0 oO_RDWR:O_CREAT:O_LOV_DELAY_CREATE:T1050000c
+
+       $CHECKSTAT -s 1050000 $DIR/$tdir/f0 || error "checkstat failed"
+       # open/write it again to force delayed layout creation
+       cat /etc/hosts > $DIR/$tdir/f0 &
+       catpid=$!
+
+       # restart OSTs
+       for num in $(seq $OSTCOUNT); do
+               start ost$num $(ostdevname $num) $OST_MOUNT_OPTS ||
+                       error "ost$num failed to start"
+       done
+
+       wait $catpid || error "cat failed"
+
+       cmp /etc/hosts $DIR/$tdir/f0 || error "cmp failed"
+       [[ $($GETSTRIPE -c $DIR/$tdir/f0) == 2 ]] || error "wrong stripecount"
+
+}
+run_test 27F "Client resend delayed layout creation with non-zero size"
+

 # createtest also checks that device nodes are created and
 # then visible correctly (#2091)
 test_28() { # bug 2091
 # createtest also checks that device nodes are created and
 # then visible correctly (#2091)
 test_28() { # bug 2091