Whamcloud - gitweb
LU-1914 ldlm: add doxygen comments
[fs/lustre-release.git] / lustre / lov / lov_lock.c
index d633309..1faf299 100644 (file)
@@ -1,6 +1,4 @@
-/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
- * vim:expandtab:shiftwidth=8:tabstop=8:
- *
+/*
  * GPL HEADER START
  *
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
@@ -28,6 +26,8 @@
 /*
  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
+ *
+ * Copyright (c) 2011, 2012, Whamcloud, Inc.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
@@ -155,7 +155,7 @@ static struct cl_lock *lov_sublock_alloc(const struct lu_env *env,
 
                 parent = lck->lls_cl.cls_lock;
                 lls    = &lck->lls_sub[idx];
-                descr  = &lls->sub_descr;
+                descr  = &lls->sub_got;
 
                 subenv = lov_sublock_env_get(env, parent, lls);
                 if (!IS_ERR(subenv)) {
@@ -267,12 +267,14 @@ static int lov_subresult(int result, int rc)
         int result_rank;
         int rc_rank;
 
-        LASSERT(result <= 0 || result == CLO_REPEAT || result == CLO_WAIT);
-        LASSERT(rc <= 0 || rc == CLO_REPEAT || rc == CLO_WAIT);
-        CLASSERT(CLO_WAIT < CLO_REPEAT);
-
         ENTRY;
 
+       LASSERTF(result <= 0 || result == CLO_REPEAT || result == CLO_WAIT,
+                "result = %d", result);
+       LASSERTF(rc <= 0 || rc == CLO_REPEAT || rc == CLO_WAIT,
+                "rc = %d\n", rc);
+        CLASSERT(CLO_WAIT < CLO_REPEAT);
+
         /* calculate ranks in the ordering above */
         result_rank = result < 0 ? 1 + CLO_REPEAT : result;
         rc_rank = rc < 0 ? 1 + CLO_REPEAT : rc;
@@ -316,7 +318,7 @@ static int lov_lock_sub_init(const struct lu_env *env,
                  * XXX for wide striping smarter algorithm is desirable,
                  * breaking out of the loop, early.
                  */
-                if (lov_stripe_intersects(r0->lo_lsm, i,
+               if (lov_stripe_intersects(loo->lo_lsm, i,
                                           file_start, file_end, &start, &end))
                         nr++;
         }
@@ -334,7 +336,7 @@ static int lov_lock_sub_init(const struct lu_env *env,
          * top-lock.
          */
         for (i = 0, nr = 0; i < r0->lo_nr; ++i) {
-                if (lov_stripe_intersects(r0->lo_lsm, i,
+               if (lov_stripe_intersects(loo->lo_lsm, i,
                                           file_start, file_end, &start, &end)) {
                         struct cl_lock_descr *descr;
 
@@ -524,17 +526,20 @@ static int lov_lock_enqueue_one(const struct lu_env *env, struct lov_lock *lck,
 
         /* first, try to enqueue a sub-lock ... */
         result = cl_enqueue_try(env, sublock, io, enqflags);
-        if (sublock->cll_state == CLS_ENQUEUED)
-                /* if it is enqueued, try to `wait' on it---maybe it's already
-                 * granted */
-                result = cl_wait_try(env, sublock);
+       if ((sublock->cll_state == CLS_ENQUEUED) && !(enqflags & CEF_AGL)) {
+               /* if it is enqueued, try to `wait' on it---maybe it's already
+                * granted */
+               result = cl_wait_try(env, sublock);
+               if (result == CLO_REENQUEUED)
+                       result = CLO_WAIT;
+       }
         /*
          * If CEF_ASYNC flag is set, then all sub-locks can be enqueued in
          * parallel, otherwise---enqueue has to wait until sub-lock is granted
          * before proceeding to the next one.
          */
-        if (result == CLO_WAIT && sublock->cll_state <= CLS_HELD &&
-            enqflags & CEF_ASYNC && !last)
+        if ((result == CLO_WAIT) && (sublock->cll_state <= CLS_HELD) &&
+            (enqflags & CEF_ASYNC) && (!last || (enqflags & CEF_AGL)))
                 result = 0;
         RETURN(result);
 }
@@ -697,7 +702,8 @@ static int lov_lock_unuse(const struct lu_env *env,
                 rc = lov_sublock_lock(env, lck, lls, closure, &subenv);
                 if (rc == 0) {
                         if (lls->sub_flags & LSF_HELD) {
-                                LASSERT(sublock->cll_state == CLS_HELD);
+                                LASSERT(sublock->cll_state == CLS_HELD ||
+                                        sublock->cll_state == CLS_ENQUEUED);
                                 rc = cl_unuse_try(subenv->lse_env, sublock);
                                 rc = lov_sublock_release(env, lck, i, 0, rc);
                         }
@@ -750,17 +756,9 @@ static void lov_lock_cancel(const struct lu_env *env,
 
                         switch(sublock->cll_state) {
                         case CLS_HELD:
-                                rc = cl_unuse_try(subenv->lse_env,
-                                                  sublock);
+                               rc = cl_unuse_try(subenv->lse_env, sublock);
                                 lov_sublock_release(env, lck, i, 0, 0);
                                 break;
-                        case CLS_ENQUEUED:
-                                /* TODO: it's not a good idea to cancel this
-                                 * lock because it's innocent. But it's
-                                 * acceptable. The better way would be to
-                                 * define a new lock method to unhold the
-                                 * dlm lock. */
-                                cl_lock_cancel(env, sublock);
                         default:
                                 lov_sublock_release(env, lck, i, 1, 0);
                                 break;
@@ -789,12 +787,15 @@ static int lov_lock_wait(const struct lu_env *env,
         struct lov_lock        *lck     = cl2lov_lock(slice);
         struct cl_lock_closure *closure = lov_closure_get(env, slice->cls_lock);
         enum cl_lock_state      minstate;
+        int                     reenqueued;
         int                     result;
         int                     i;
 
         ENTRY;
 
-        for (result = 0, minstate = CLS_FREEING, i = 0; i < lck->lls_nr; ++i) {
+again:
+        for (result = 0, minstate = CLS_FREEING, i = 0, reenqueued = 0;
+             i < lck->lls_nr; ++i) {
                 int rc;
                 struct lovsub_lock     *sub;
                 struct cl_lock         *sublock;
@@ -814,10 +815,18 @@ static int lov_lock_wait(const struct lu_env *env,
                         minstate = min(minstate, sublock->cll_state);
                         lov_sublock_unlock(env, sub, closure, subenv);
                 }
+                if (rc == CLO_REENQUEUED) {
+                        reenqueued++;
+                        rc = 0;
+                }
                 result = lov_subresult(result, rc);
                 if (result != 0)
                         break;
         }
+        /* Each sublock only can be reenqueued once, so will not loop for
+         * ever. */
+        if (result == 0 && reenqueued != 0)
+                goto again;
         cl_lock_closure_fini(closure);
         RETURN(result ?: minstate >= CLS_HELD ? 0 : CLO_WAIT);
 }
@@ -863,6 +872,11 @@ static int lov_lock_use(const struct lu_env *env,
                                 if (rc != 0)
                                         rc = lov_sublock_release(env, lck,
                                                                  i, 1, rc);
+                        } else if (sublock->cll_state == CLS_NEW) {
+                                /* Sub-lock might have been canceled, while
+                                 * top-lock was cached. */
+                                result = -ESTALE;
+                                lov_sublock_release(env, lck, i, 1, result);
                         }
                         lov_sublock_unlock(env, sub, closure, subenv);
                 }
@@ -910,7 +924,7 @@ static int lock_lock_multi_match()
                 if (sub->sub_lock == NULL)
                         continue;
                 subobj = sub->sub_descr.cld_obj;
-                if (!lov_stripe_intersects(r0->lo_lsm, sub->sub_stripe,
+               if (!lov_stripe_intersects(loo->lo_lsm, sub->sub_stripe,
                                            fstart, fend, &start, &end))
                         continue;
                 subneed->cld_start = cl_index(subobj, start);
@@ -934,7 +948,7 @@ static int lov_lock_stripe_is_matching(const struct lu_env *env,
                                        const struct cl_lock_descr *child,
                                        const struct cl_lock_descr *descr)
 {
-        struct lov_stripe_md *lsm = lov_r0(lov)->lo_lsm;
+       struct lov_stripe_md *lsm = lov->lo_lsm;
         obd_off start;
         obd_off end;
         int result;
@@ -993,6 +1007,11 @@ static int lov_lock_fits_into(const struct lu_env *env,
 
         ENTRY;
 
+       /* for top lock, it's necessary to match enq flags otherwise it will
+        * run into problem if a sublock is missing and reenqueue. */
+       if (need->cld_enq_flags != lov->lls_orig.cld_enq_flags)
+               return 0;
+
         if (need->cld_mode == CLM_GROUP)
                 /*
                  * always allow to match group lock.
@@ -1172,6 +1191,41 @@ int lov_lock_init_raid0(const struct lu_env *env, struct cl_object *obj,
         RETURN(result);
 }
 
+static void lov_empty_lock_fini(const struct lu_env *env,
+                               struct cl_lock_slice *slice)
+{
+       struct lov_lock *lck = cl2lov_lock(slice);
+       OBD_SLAB_FREE_PTR(lck, lov_lock_kmem);
+}
+
+static int lov_empty_lock_print(const struct lu_env *env, void *cookie,
+                       lu_printer_t p, const struct cl_lock_slice *slice)
+{
+       (*p)(env, cookie, "empty\n");
+       return 0;
+}
+
+static const struct cl_lock_operations lov_empty_lock_ops = {
+       .clo_fini  = lov_empty_lock_fini,
+       .clo_print = lov_empty_lock_print
+};
+
+int lov_lock_init_empty(const struct lu_env *env, struct cl_object *obj,
+               struct cl_lock *lock, const struct cl_io *io)
+{
+       struct lov_lock *lck;
+       int result = -ENOMEM;
+
+       ENTRY;
+       OBD_SLAB_ALLOC_PTR_GFP(lck, lov_lock_kmem, CFS_ALLOC_IO);
+       if (lck != NULL) {
+               cl_lock_slice_add(lock, &lck->lls_cl, obj, &lov_empty_lock_ops);
+               lck->lls_orig = lock->cll_descr;
+               result = 0;
+       }
+       RETURN(result);
+}
+
 static struct cl_lock_closure *lov_closure_get(const struct lu_env *env,
                                                struct cl_lock *parent)
 {