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LU-1299 clio: a combo patch to fix cl_lock
[fs/lustre-release.git] / lustre / obdclass / cl_lock.c
index d61fd6f..ff9ffec 100644 (file)
@@ -597,7 +597,6 @@ struct cl_lock *cl_lock_peek(const struct lu_env *env, const struct cl_io *io,
         struct cl_object_header *head;
         struct cl_object        *obj;
         struct cl_lock          *lock;
-        int ok;
 
         obj  = need->cld_obj;
         head = cl_object_header(obj);
@@ -612,20 +611,18 @@ struct cl_lock *cl_lock_peek(const struct lu_env *env, const struct cl_io *io,
         cl_lock_mutex_get(env, lock);
         if (lock->cll_state == CLS_INTRANSIT)
                 cl_lock_state_wait(env, lock); /* Don't care return value. */
-        if (lock->cll_state == CLS_CACHED) {
-                int result;
-                result = cl_use_try(env, lock, 1);
-                if (result < 0)
-                        cl_lock_error(env, lock, result);
-        }
-        ok = lock->cll_state == CLS_HELD;
-        if (ok) {
-                cl_lock_hold_add(env, lock, scope, source);
-                cl_lock_user_add(env, lock);
+        cl_lock_hold_add(env, lock, scope, source);
+        cl_lock_user_add(env, lock);
+        if (lock->cll_state == CLS_CACHED)
+                cl_use_try(env, lock, 1);
+        if (lock->cll_state == CLS_HELD) {
+                cl_lock_mutex_put(env, lock);
+                cl_lock_lockdep_acquire(env, lock, 0);
                 cl_lock_put(env, lock);
-        }
-        cl_lock_mutex_put(env, lock);
-        if (!ok) {
+        } else {
+                cl_unuse_try(env, lock);
+                cl_lock_unhold(env, lock, scope, source);
+                cl_lock_mutex_put(env, lock);
                 cl_lock_put(env, lock);
                 lock = NULL;
         }
@@ -907,8 +904,10 @@ static void cl_lock_hold_release(const struct lu_env *env, struct cl_lock *lock,
         lu_ref_del(&lock->cll_holders, scope, source);
         cl_lock_hold_mod(env, lock, -1);
         if (lock->cll_holds == 0) {
+                CL_LOCK_ASSERT(lock->cll_state != CLS_HELD, env, lock);
                 if (lock->cll_descr.cld_mode == CLM_PHANTOM ||
-                    lock->cll_descr.cld_mode == CLM_GROUP)
+                    lock->cll_descr.cld_mode == CLM_GROUP ||
+                    lock->cll_state != CLS_CACHED)
                         /*
                          * If lock is still phantom or grouplock when user is
                          * done with it---destroy the lock.
@@ -973,12 +972,17 @@ int cl_lock_state_wait(const struct lu_env *env, struct cl_lock *lock)
                 cl_lock_mutex_put(env, lock);
 
                 LASSERT(cl_lock_nr_mutexed(env) == 0);
-                cfs_waitq_wait(&waiter, CFS_TASK_INTERRUPTIBLE);
+
+                result = -EINTR;
+                if (likely(!OBD_FAIL_CHECK(OBD_FAIL_LOCK_STATE_WAIT_INTR))) {
+                        cfs_waitq_wait(&waiter, CFS_TASK_INTERRUPTIBLE);
+                        if (!cfs_signal_pending())
+                                result = 0;
+                }
 
                 cl_lock_mutex_get(env, lock);
                 cfs_set_current_state(CFS_TASK_RUNNING);
                 cfs_waitq_del(&lock->cll_wq, &waiter);
-                result = cfs_signal_pending() ? -EINTR : 0;
 
                 /* Restore old blocked signals */
                 cfs_restore_sigs(blocked);
@@ -1188,12 +1192,12 @@ int cl_enqueue_try(const struct lu_env *env, struct cl_lock *lock,
         ENTRY;
         cl_lock_trace(D_DLMTRACE, env, "enqueue lock", lock);
         do {
-                result = 0;
-
                 LINVRNT(cl_lock_is_mutexed(lock));
 
-                if (lock->cll_error != 0)
+                result = lock->cll_error;
+                if (result != 0)
                         break;
+
                 switch (lock->cll_state) {
                 case CLS_NEW:
                         cl_lock_state_set(env, lock, CLS_QUEUING);
@@ -1226,9 +1230,7 @@ int cl_enqueue_try(const struct lu_env *env, struct cl_lock *lock,
                         LBUG();
                 }
         } while (result == CLO_REPEAT);
-        if (result < 0)
-                cl_lock_error(env, lock, result);
-        RETURN(result ?: lock->cll_error);
+        RETURN(result);
 }
 EXPORT_SYMBOL(cl_enqueue_try);
 
@@ -1257,6 +1259,7 @@ int cl_lock_enqueue_wait(const struct lu_env *env,
         LASSERT(cl_lock_nr_mutexed(env) == 0);
 
         cl_lock_mutex_get(env, conflict);
+        cl_lock_trace(D_DLMTRACE, env, "enqueue wait", conflict);
         cl_lock_cancel(env, conflict);
         cl_lock_delete(env, conflict);
 
@@ -1301,10 +1304,8 @@ static int cl_enqueue_locked(const struct lu_env *env, struct cl_lock *lock,
                 }
                 break;
         } while (1);
-        if (result != 0) {
-                cl_lock_user_del(env, lock);
-                cl_lock_error(env, lock, result);
-        }
+        if (result != 0)
+                cl_unuse_try(env, lock);
         LASSERT(ergo(result == 0, lock->cll_state == CLS_ENQUEUED ||
                      lock->cll_state == CLS_HELD));
         RETURN(result);
@@ -1341,13 +1342,11 @@ EXPORT_SYMBOL(cl_enqueue);
 /**
  * Tries to unlock a lock.
  *
- * This function is called repeatedly by cl_unuse() until either lock is
- * unlocked, or error occurs.
- * cl_unuse_try is a one-shot operation, so it must NOT return CLO_WAIT.
- *
- * \pre  lock->cll_state == CLS_HELD
+ * This function is called to release underlying resource:
+ * 1. for top lock, the resource is sublocks it held;
+ * 2. for sublock, the resource is the reference to dlmlock.
  *
- * \post ergo(result == 0, lock->cll_state == CLS_CACHED)
+ * cl_unuse_try is a one-shot operation, so it must NOT return CLO_WAIT.
  *
  * \see cl_unuse() cl_lock_operations::clo_unuse()
  * \see cl_lock_state::CLS_CACHED
@@ -1360,12 +1359,18 @@ int cl_unuse_try(const struct lu_env *env, struct cl_lock *lock)
         ENTRY;
         cl_lock_trace(D_DLMTRACE, env, "unuse lock", lock);
 
-        LASSERT(lock->cll_state == CLS_HELD || lock->cll_state == CLS_ENQUEUED);
         if (lock->cll_users > 1) {
                 cl_lock_user_del(env, lock);
                 RETURN(0);
         }
 
+        /* Only if the lock is in CLS_HELD or CLS_ENQUEUED state, it can hold
+         * underlying resources. */
+        if (!(lock->cll_state == CLS_HELD || lock->cll_state == CLS_ENQUEUED)) {
+                cl_lock_user_del(env, lock);
+                RETURN(0);
+        }
+
         /*
          * New lock users (->cll_users) are not protecting unlocking
          * from proceeding. From this point, lock eventually reaches
@@ -1405,29 +1410,16 @@ int cl_unuse_try(const struct lu_env *env, struct cl_lock *lock)
                  */
                 result = 0;
         } else {
-                CERROR("result = %d, this is unlikely!\n", result);
-                cl_lock_extransit(env, lock, state);
+                CL_LOCK_DEBUG(D_ERROR, env, lock, "unuse return %d\n", result);
+                /* Set the lock state to CLS_NEW so it will be destroyed.
+                 * In lov_lock_unuse() it will release sublocks even if error
+                 * occurs. */
+                cl_lock_extransit(env, lock, CLS_NEW);
         }
-
-        result = result ?: lock->cll_error;
-        if (result < 0)
-                cl_lock_error(env, lock, result);
-        RETURN(result);
+        RETURN(result ?: lock->cll_error);
 }
 EXPORT_SYMBOL(cl_unuse_try);
 
-static void cl_unuse_locked(const struct lu_env *env, struct cl_lock *lock)
-{
-        int result;
-        ENTRY;
-
-        result = cl_unuse_try(env, lock);
-        if (result)
-                CL_LOCK_DEBUG(D_ERROR, env, lock, "unuse return %d\n", result);
-
-        EXIT;
-}
-
 /**
  * Unlocks a lock.
  */
@@ -1435,7 +1427,7 @@ void cl_unuse(const struct lu_env *env, struct cl_lock *lock)
 {
         ENTRY;
         cl_lock_mutex_get(env, lock);
-        cl_unuse_locked(env, lock);
+        cl_unuse_try(env, lock);
         cl_lock_mutex_put(env, lock);
         cl_lock_lockdep_release(env, lock);
         EXIT;
@@ -1468,8 +1460,8 @@ int cl_wait_try(const struct lu_env *env, struct cl_lock *lock)
                 LASSERT(lock->cll_users > 0);
                 LASSERT(lock->cll_holds > 0);
 
-                result = 0;
-                if (lock->cll_error != 0)
+                result = lock->cll_error;
+                if (result != 0)
                         break;
 
                 if (cl_lock_is_intransit(lock)) {
@@ -1495,7 +1487,7 @@ int cl_wait_try(const struct lu_env *env, struct cl_lock *lock)
                         cl_lock_state_set(env, lock, CLS_HELD);
                 }
         } while (result == CLO_REPEAT);
-        RETURN(result ?: lock->cll_error);
+        RETURN(result);
 }
 EXPORT_SYMBOL(cl_wait_try);
 
@@ -1530,8 +1522,7 @@ int cl_wait(const struct lu_env *env, struct cl_lock *lock)
                 break;
         } while (1);
         if (result < 0) {
-                cl_lock_user_del(env, lock);
-                cl_lock_error(env, lock, result);
+                cl_unuse_try(env, lock);
                 cl_lock_lockdep_release(env, lock);
         }
         cl_lock_trace(D_DLMTRACE, env, "wait lock", lock);
@@ -1799,8 +1790,8 @@ void cl_lock_error(const struct lu_env *env, struct cl_lock *lock, int error)
         LINVRNT(cl_lock_invariant(env, lock));
 
         ENTRY;
-        cl_lock_trace(D_DLMTRACE, env, "set lock error", lock);
         if (lock->cll_error == 0 && error != 0) {
+                cl_lock_trace(D_DLMTRACE, env, "set lock error", lock);
                 lock->cll_error = error;
                 cl_lock_signal(env, lock);
                 cl_lock_cancel(env, lock);
@@ -1840,9 +1831,9 @@ EXPORT_SYMBOL(cl_lock_cancel);
  * Finds an existing lock covering given page and optionally different from a
  * given \a except lock.
  */
-struct cl_lock *cl_lock_at_page(const struct lu_env *env, struct cl_object *obj,
-                                struct cl_page *page, struct cl_lock *except,
-                                int pending, int canceld)
+struct cl_lock *cl_lock_at_pgoff(const struct lu_env *env, struct cl_object *obj,
+                                 pgoff_t index, struct cl_lock *except,
+                                 int pending, int canceld)
 {
         struct cl_object_header *head;
         struct cl_lock          *scan;
@@ -1857,7 +1848,7 @@ struct cl_lock *cl_lock_at_page(const struct lu_env *env, struct cl_object *obj,
 
         need->cld_mode = CLM_READ; /* CLM_READ matches both READ & WRITE, but
                                     * not PHANTOM */
-        need->cld_start = need->cld_end = page->cp_index;
+        need->cld_start = need->cld_end = index;
         need->cld_enq_flags = 0;
 
         cfs_spin_lock(&head->coh_lock_guard);
@@ -1886,7 +1877,7 @@ struct cl_lock *cl_lock_at_page(const struct lu_env *env, struct cl_object *obj,
         cfs_spin_unlock(&head->coh_lock_guard);
         RETURN(lock);
 }
-EXPORT_SYMBOL(cl_lock_at_page);
+EXPORT_SYMBOL(cl_lock_at_pgoff);
 
 /**
  * Calculate the page offset at the layer of @lock.
@@ -1917,8 +1908,8 @@ static int check_and_discard_cb(const struct lu_env *env, struct cl_io *io,
                 struct cl_lock *tmp;
 
                 /* refresh non-overlapped index */
-                tmp = cl_lock_at_page(env, lock->cll_descr.cld_obj, page, lock,
-                                      1, 0);
+                tmp = cl_lock_at_pgoff(env, lock->cll_descr.cld_obj, index, lock,
+                                       1, 0);
                 if (tmp != NULL) {
                         /* Cache the first-non-overlapped index so as to skip
                          * all pages within [index, clt_fn_index). This
@@ -2171,7 +2162,7 @@ struct cl_lock *cl_lock_request(const struct lu_env *env, struct cl_io *io,
                                                                 lock, enqflags);
                                         break;
                                 }
-                                cl_unuse_locked(env, lock);
+                                cl_unuse_try(env, lock);
                         }
                         cl_lock_trace(D_DLMTRACE, env, "enqueue failed", lock);
                         cl_lock_hold_release(env, lock, scope, source);