LU-10664 dom: non-blocking enqueue for DOM locks

[fs/lustre-release.git] / lustre / mdt / mdt_lvb.c

diff --git a/lustre/mdt/mdt_lvb.c b/lustre/mdt/mdt_lvb.c
index 1a5e8ba..0e6079b 100644 (file)
--- a/lustre/mdt/mdt_lvb.c
+++ b/lustre/mdt/mdt_lvb.c
@@ -292,6 +292,11 @@ static int mdt_lvbo_size(struct ldlm_lock *lock)
                return qmt_hdls.qmth_lvbo_size(mdt->mdt_qmt_dev, lock);
        }
 
+       /* Always prefer DoM LVB data because layout is never returned in
+        * LVB when lock bits are combined with DoM, this is either GETATTR
+        * or OPEN enqueue. Meanwhile GL AST can be issued on such combined
+        * lock bits and it uses LVB for DoM data.
+        */
        if (ldlm_has_dom(lock))
                return sizeof(struct ost_lvb);
 
@@ -355,22 +360,23 @@ static int mdt_lvbo_fill(struct ldlm_lock *lock,
                        GOTO(out, rc = -ENOMEM);
        }
 
-       /* LVB for DoM lock is needed only for glimpse,
-        * don't fill DoM data if there is layout lock */
+       /* DOM LVB is used by glimpse and IO completion when
+        * DoM bits is always alone.
+        * If DoM bit is combined with any other bit then it is
+        * intent OPEN or GETATTR lock which is not filling
+        * LVB buffer in reply neither for DoM nor for LAYOUT.
+        */
        if (ldlm_has_dom(lock)) {
                struct ldlm_resource *res = lock->l_resource;
                int lvb_len = sizeof(struct ost_lvb);
 
                if (!mdt_dom_lvb_is_valid(res))
-                       mdt_dom_lvbo_update(lock->l_resource, lock, NULL, 0);
-
-               if (lvb_len > *lvblen)
-                       lvb_len = *lvblen;
+                       mdt_dom_lvbo_update(res, lock, NULL, 0);
 
+               LASSERT(*lvblen >= lvb_len);
                lock_res(res);
                memcpy(lvb, res->lr_lvb_data, lvb_len);
                unlock_res(res);
-
                GOTO(out, rc = lvb_len);
        }