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LU-12616 obclass: fix MDS start/stop race
[fs/lustre-release.git] / lustre / ldlm / ldlm_extent.c
index 6975201..9e046c9 100644 (file)
@@ -23,7 +23,7 @@
  * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
  *
- * Copyright (c) 2010, 2013, Intel Corporation.
+ * Copyright (c) 2010, 2017, Intel Corporation.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
@@ -130,7 +130,10 @@ static void ldlm_extent_internal_policy_granted(struct ldlm_lock *req,
        __u64 req_start = req->l_req_extent.start;
        __u64 req_end = req->l_req_extent.end;
        struct ldlm_interval_tree *tree;
-       struct interval_node_extent limiter = { new_ex->start, new_ex->end };
+       struct interval_node_extent limiter = {
+               .start  = new_ex->start,
+               .end    = new_ex->end,
+       };
        int conflicting = 0;
        int idx;
        ENTRY;
@@ -139,7 +142,10 @@ static void ldlm_extent_internal_policy_granted(struct ldlm_lock *req,
 
        /* Using interval tree to handle the LDLM extent granted locks. */
         for (idx = 0; idx < LCK_MODE_NUM; idx++) {
-                struct interval_node_extent ext = { req_start, req_end };
+               struct interval_node_extent ext = {
+                       .start  = req_start,
+                       .end    = req_end,
+               };
 
                 tree = &res->lr_itree[idx];
                 if (lockmode_compat(tree->lit_mode, req_mode))
@@ -263,38 +269,49 @@ ldlm_extent_internal_policy_waiting(struct ldlm_lock *req,
 static void ldlm_extent_policy(struct ldlm_resource *res,
                               struct ldlm_lock *lock, __u64 *flags)
 {
-        struct ldlm_extent new_ex = { .start = 0, .end = OBD_OBJECT_EOF };
-
-        if (lock->l_export == NULL)
-                /*
-                 * this is local lock taken by server (e.g., as a part of
-                 * OST-side locking, or unlink handling). Expansion doesn't
-                 * make a lot of sense for local locks, because they are
-                 * dropped immediately on operation completion and would only
-                 * conflict with other threads.
-                 */
-                return;
+       struct ldlm_extent new_ex = { .start = 0, .end = OBD_OBJECT_EOF };
+
+       if (lock->l_export == NULL)
+               /*
+                * this is a local lock taken by server (e.g., as a part of
+                * OST-side locking, or unlink handling). Expansion doesn't
+                * make a lot of sense for local locks, because they are
+                * dropped immediately on operation completion and would only
+                * conflict with other threads.
+                */
+               return;
 
-        if (lock->l_policy_data.l_extent.start == 0 &&
-            lock->l_policy_data.l_extent.end == OBD_OBJECT_EOF)
-                /* fast-path whole file locks */
-                return;
+       if (lock->l_policy_data.l_extent.start == 0 &&
+           lock->l_policy_data.l_extent.end == OBD_OBJECT_EOF)
+               /* fast-path whole file locks */
+               return;
 
-        ldlm_extent_internal_policy_granted(lock, &new_ex);
-        ldlm_extent_internal_policy_waiting(lock, &new_ex);
+       /* Because reprocess_queue zeroes flags and uses it to return
+        * LDLM_FL_LOCK_CHANGED, we must check for the NO_EXPANSION flag
+        * in the lock flags rather than the 'flags' argument */
+       if (likely(!(lock->l_flags & LDLM_FL_NO_EXPANSION))) {
+               ldlm_extent_internal_policy_granted(lock, &new_ex);
+               ldlm_extent_internal_policy_waiting(lock, &new_ex);
+       } else {
+               LDLM_DEBUG(lock, "Not expanding manually requested lock.\n");
+               new_ex.start = lock->l_policy_data.l_extent.start;
+               new_ex.end = lock->l_policy_data.l_extent.end;
+               /* In case the request is not on correct boundaries, we call
+                * fixup. (normally called in ldlm_extent_internal_policy_*) */
+               ldlm_extent_internal_policy_fixup(lock, &new_ex, 0);
+       }
 
-        if (new_ex.start != lock->l_policy_data.l_extent.start ||
-            new_ex.end != lock->l_policy_data.l_extent.end) {
-                *flags |= LDLM_FL_LOCK_CHANGED;
-                lock->l_policy_data.l_extent.start = new_ex.start;
-                lock->l_policy_data.l_extent.end = new_ex.end;
-        }
+       if (!ldlm_extent_equal(&new_ex, &lock->l_policy_data.l_extent)) {
+               *flags |= LDLM_FL_LOCK_CHANGED;
+               lock->l_policy_data.l_extent.start = new_ex.start;
+               lock->l_policy_data.l_extent.end = new_ex.end;
+       }
 }
 
 static int ldlm_check_contention(struct ldlm_lock *lock, int contended_locks)
 {
        struct ldlm_resource *res = lock->l_resource;
-       cfs_time_t now = cfs_time_current();
+       time64_t now = ktime_get_seconds();
 
        if (OBD_FAIL_CHECK(OBD_FAIL_LDLM_SET_CONTENTION))
                return 1;
@@ -302,8 +319,9 @@ static int ldlm_check_contention(struct ldlm_lock *lock, int contended_locks)
        CDEBUG(D_DLMTRACE, "contended locks = %d\n", contended_locks);
        if (contended_locks > ldlm_res_to_ns(res)->ns_contended_locks)
                res->lr_contention_time = now;
-       return cfs_time_before(now, cfs_time_add(res->lr_contention_time,
-               cfs_time_seconds(ldlm_res_to_ns(res)->ns_contention_time)));
+
+       return now < res->lr_contention_time +
+                    ldlm_res_to_ns(res)->ns_contention_time;
 }
 
 struct ldlm_extent_compat_args {
@@ -415,7 +433,8 @@ ldlm_extent_compat_queue(struct list_head *queue, struct ldlm_lock *req,
                         }
 
                         if (tree->lit_mode == LCK_GROUP) {
-                                if (*flags & LDLM_FL_BLOCK_NOWAIT) {
+                               if (*flags & (LDLM_FL_BLOCK_NOWAIT |
+                                             LDLM_FL_SPECULATIVE)) {
                                         compat = -EWOULDBLOCK;
                                         goto destroylock;
                                 }
@@ -432,10 +451,24 @@ ldlm_extent_compat_queue(struct list_head *queue, struct ldlm_lock *req,
                                 continue;
                         }
 
-                        if (!work_list) {
-                                rc = interval_is_overlapped(tree->lit_root,&ex);
-                                if (rc)
-                                        RETURN(0);
+                       /* We've found a potentially blocking lock, check
+                        * compatibility.  This handles locks other than GROUP
+                        * locks, which are handled separately above.
+                        *
+                        * Locks with FL_SPECULATIVE are asynchronous requests
+                        * which must never wait behind another lock, so they
+                        * fail if any conflicting lock is found. */
+                       if (!work_list || (*flags & LDLM_FL_SPECULATIVE)) {
+                               rc = interval_is_overlapped(tree->lit_root,
+                                                           &ex);
+                               if (rc) {
+                                       if (!work_list) {
+                                               RETURN(0);
+                                       } else {
+                                               compat = -EWOULDBLOCK;
+                                               goto destroylock;
+                                       }
+                               }
                         } else {
                                 interval_search(tree->lit_root, &ex,
                                                 ldlm_extent_compat_cb, &data);
@@ -522,8 +555,8 @@ ldlm_extent_compat_queue(struct list_head *queue, struct ldlm_lock *req,
                                     lock->l_policy_data.l_extent.gid) {
                                         /* If existing lock with matched gid is granted,
                                            we grant new one too. */
-                                        if (lock->l_req_mode == lock->l_granted_mode)
-                                                RETURN(2);
+                                       if (ldlm_is_granted(lock))
+                                               RETURN(2);
 
                                         /* Otherwise we are scanning queue of waiting
                                          * locks and it means current request would
@@ -531,7 +564,8 @@ ldlm_extent_compat_queue(struct list_head *queue, struct ldlm_lock *req,
                                          * already blocked.
                                          * If we are in nonblocking mode - return
                                          * immediately */
-                                        if (*flags & LDLM_FL_BLOCK_NOWAIT) {
+                                       if (*flags & (LDLM_FL_BLOCK_NOWAIT
+                                                     | LDLM_FL_SPECULATIVE)) {
                                                 compat = -EWOULDBLOCK;
                                                 goto destroylock;
                                         }
@@ -550,8 +584,8 @@ ldlm_extent_compat_queue(struct list_head *queue, struct ldlm_lock *req,
                                 }
                         }
 
-                        if (unlikely(req_mode == LCK_GROUP &&
-                                     (lock->l_req_mode != lock->l_granted_mode))) {
+                       if (unlikely(req_mode == LCK_GROUP &&
+                                    !ldlm_is_granted(lock))) {
                                 scan = 1;
                                 compat = 0;
                                 if (lock->l_req_mode != LCK_GROUP) {
@@ -574,10 +608,11 @@ ldlm_extent_compat_queue(struct list_head *queue, struct ldlm_lock *req,
                         }
 
                         if (unlikely(lock->l_req_mode == LCK_GROUP)) {
-                                /* If compared lock is GROUP, then requested is PR/PW/
-                                 * so this is not compatible; extent range does not
-                                 * matter */
-                                if (*flags & LDLM_FL_BLOCK_NOWAIT) {
+                               /* If compared lock is GROUP, then requested is
+                                * PR/PW so this is not compatible; extent
+                                * range does not matter */
+                               if (*flags & (LDLM_FL_BLOCK_NOWAIT
+                                             | LDLM_FL_SPECULATIVE)) {
                                         compat = -EWOULDBLOCK;
                                         goto destroylock;
                                 } else {
@@ -596,6 +631,11 @@ ldlm_extent_compat_queue(struct list_head *queue, struct ldlm_lock *req,
                         if (!work_list)
                                 RETURN(0);
 
+                       if (*flags & LDLM_FL_SPECULATIVE) {
+                               compat = -EWOULDBLOCK;
+                               goto destroylock;
+                       }
+
                         /* don't count conflicting glimpse locks */
                         if (lock->l_req_mode == LCK_PR &&
                             lock->l_policy_data.l_extent.start == 0 &&
@@ -636,7 +676,9 @@ destroylock:
 void ldlm_lock_prolong_one(struct ldlm_lock *lock,
                           struct ldlm_prolong_args *arg)
 {
-       int timeout;
+       time64_t timeout;
+
+       OBD_FAIL_TIMEOUT(OBD_FAIL_LDLM_PROLONG_PAUSE, 3);
 
        if (arg->lpa_export != lock->l_export ||
            lock->l_flags & LDLM_FL_DESTROYED)
@@ -654,7 +696,7 @@ void ldlm_lock_prolong_one(struct ldlm_lock *lock,
         */
        timeout = arg->lpa_timeout + (ldlm_bl_timeout(lock) >> 1);
 
-       LDLM_DEBUG(lock, "refreshed to %ds.\n", timeout);
+       LDLM_DEBUG(lock, "refreshed to %llds.\n", timeout);
 
        arg->lpa_blocks_cnt++;
 
@@ -731,34 +773,6 @@ void ldlm_resource_prolong(struct ldlm_prolong_args *arg)
 }
 EXPORT_SYMBOL(ldlm_resource_prolong);
 
-
-/**
- * Discard all AST work items from list.
- *
- * If for whatever reason we do not want to send ASTs to conflicting locks
- * anymore, disassemble the list with this function.
- */
-static void discard_bl_list(struct list_head *bl_list)
-{
-       struct list_head *tmp, *pos;
-        ENTRY;
-
-       list_for_each_safe(pos, tmp, bl_list) {
-                struct ldlm_lock *lock =
-                       list_entry(pos, struct ldlm_lock, l_bl_ast);
-
-               list_del_init(&lock->l_bl_ast);
-               LASSERT(ldlm_is_ast_sent(lock));
-               ldlm_clear_ast_sent(lock);
-                LASSERT(lock->l_bl_ast_run == 0);
-                LASSERT(lock->l_blocking_lock);
-                LDLM_LOCK_RELEASE(lock->l_blocking_lock);
-                lock->l_blocking_lock = NULL;
-                LDLM_LOCK_RELEASE(lock);
-        }
-        EXIT;
-}
-
 /**
  * Process a granting attempt for extent lock.
  * Must be called with ns lock held.
@@ -766,38 +780,30 @@ static void discard_bl_list(struct list_head *bl_list)
  * This function looks for any conflicts for \a lock in the granted or
  * waiting queues. The lock is granted if no conflicts are found in
  * either queue.
- *
- * If \a first_enq is 0 (ie, called from ldlm_reprocess_queue):
- *   - blocking ASTs have already been sent
- *
- * If \a first_enq is 1 (ie, called from ldlm_lock_enqueue):
- *   - blocking ASTs have not been sent yet, so list of conflicting locks
- *     would be collected and ASTs sent.
  */
 int ldlm_process_extent_lock(struct ldlm_lock *lock, __u64 *flags,
-                            int first_enq, enum ldlm_error *err,
-                            struct list_head *work_list)
+                            enum ldlm_process_intention intention,
+                            enum ldlm_error *err, struct list_head *work_list)
 {
        struct ldlm_resource *res = lock->l_resource;
-       struct list_head rpc_list;
        int rc, rc2;
        int contended_locks = 0;
+       struct list_head *grant_work = intention == LDLM_PROCESS_ENQUEUE ?
+                                                       NULL : work_list;
        ENTRY;
 
-       LASSERT(lock->l_granted_mode != lock->l_req_mode);
-       LASSERT(list_empty(&res->lr_converting));
+       LASSERT(!ldlm_is_granted(lock));
        LASSERT(!(*flags & LDLM_FL_DENY_ON_CONTENTION) ||
                !ldlm_is_ast_discard_data(lock));
-       INIT_LIST_HEAD(&rpc_list);
        check_res_locked(res);
        *err = ELDLM_OK;
 
-        if (!first_enq) {
-                /* Careful observers will note that we don't handle -EWOULDBLOCK
-                 * here, but it's ok for a non-obvious reason -- compat_queue
-                 * can only return -EWOULDBLOCK if (flags & BLOCK_NOWAIT).
-                 * flags should always be zero here, and if that ever stops
-                 * being true, we want to find out. */
+       if (intention == LDLM_PROCESS_RESCAN) {
+               /* Careful observers will note that we don't handle -EWOULDBLOCK
+                * here, but it's ok for a non-obvious reason -- compat_queue
+                * can only return -EWOULDBLOCK if (flags & BLOCK_NOWAIT |
+                * SPECULATIVE). flags should always be zero here, and if that
+                * ever stops being true, we want to find out. */
                 LASSERT(*flags == 0);
                 rc = ldlm_extent_compat_queue(&res->lr_granted, lock, flags,
                                               err, NULL, &contended_locks);
@@ -813,84 +819,38 @@ int ldlm_process_extent_lock(struct ldlm_lock *lock, __u64 *flags,
 
                 if (!OBD_FAIL_CHECK(OBD_FAIL_LDLM_CANCEL_EVICT_RACE))
                         ldlm_extent_policy(res, lock, flags);
-                ldlm_grant_lock(lock, work_list);
+               ldlm_grant_lock(lock, grant_work);
                 RETURN(LDLM_ITER_CONTINUE);
         }
 
- restart:
         contended_locks = 0;
         rc = ldlm_extent_compat_queue(&res->lr_granted, lock, flags, err,
-                                      &rpc_list, &contended_locks);
-        if (rc < 0)
-                GOTO(out, rc); /* lock was destroyed */
-        if (rc == 2)
-                goto grant;
-
-        rc2 = ldlm_extent_compat_queue(&res->lr_waiting, lock, flags, err,
-                                       &rpc_list, &contended_locks);
-        if (rc2 < 0)
-                GOTO(out, rc = rc2); /* lock was destroyed */
-
-        if (rc + rc2 == 2) {
-        grant:
-                ldlm_extent_policy(res, lock, flags);
-                ldlm_resource_unlink_lock(lock);
-                ldlm_grant_lock(lock, NULL);
-        } else {
-                /* If either of the compat_queue()s returned failure, then we
-                 * have ASTs to send and must go onto the waiting list.
-                 *
-                 * bug 2322: we used to unlink and re-add here, which was a
-                 * terrible folly -- if we goto restart, we could get
-                 * re-ordered!  Causes deadlock, because ASTs aren't sent! */
-               if (list_empty(&lock->l_res_link))
-                        ldlm_resource_add_lock(res, &res->lr_waiting, lock);
-                unlock_res(res);
-                rc = ldlm_run_ast_work(ldlm_res_to_ns(res), &rpc_list,
-                                       LDLM_WORK_BL_AST);
-
-                if (OBD_FAIL_CHECK(OBD_FAIL_LDLM_OST_FAIL_RACE) &&
-                    !ns_is_client(ldlm_res_to_ns(res)))
-                        class_fail_export(lock->l_export);
-
-               lock_res(res);
-               if (rc == -ERESTART) {
-                       /* 15715: The lock was granted and destroyed after
-                        * resource lock was dropped. Interval node was freed
-                        * in ldlm_lock_destroy. Anyway, this always happens
-                        * when a client is being evicted. So it would be
-                        * ok to return an error. -jay */
-                       if (ldlm_is_destroyed(lock)) {
-                               *err = -EAGAIN;
-                               GOTO(out, rc = -EAGAIN);
-                       }
-
-                       /* lock was granted while resource was unlocked. */
-                       if (lock->l_granted_mode == lock->l_req_mode) {
-                               /* bug 11300: if the lock has been granted,
-                                * break earlier because otherwise, we will go
-                                * to restart and ldlm_resource_unlink will be
-                                * called and it causes the interval node to be
-                                * freed. Then we will fail at
-                                * ldlm_extent_add_lock() */
-                               *flags &= ~LDLM_FL_BLOCKED_MASK;
-                               GOTO(out, rc = 0);
-                       }
-
-                       GOTO(restart, rc);
-               }
-
-               /* this way we force client to wait for the lock
-                * endlessly once the lock is enqueued -bzzz */
-               *flags |= LDLM_FL_BLOCK_GRANTED | LDLM_FL_NO_TIMEOUT;
-
+                                     work_list, &contended_locks);
+       if (rc < 0)
+               GOTO(out_rpc_list, rc);
+
+       rc2 = 0;
+       if (rc != 2) {
+               rc2 = ldlm_extent_compat_queue(&res->lr_waiting, lock,
+                                              flags, err, work_list,
+                                              &contended_locks);
+               if (rc2 < 0)
+                       GOTO(out_rpc_list, rc = rc2);
        }
-       RETURN(0);
-out:
-       if (!list_empty(&rpc_list)) {
-               LASSERT(!ldlm_is_ast_discard_data(lock));
-               discard_bl_list(&rpc_list);
+
+       if (rc + rc2 == 2) {
+               ldlm_extent_policy(res, lock, flags);
+               ldlm_resource_unlink_lock(lock);
+               ldlm_grant_lock(lock, grant_work);
+       } else {
+               /* Adding LDLM_FL_NO_TIMEOUT flag to granted lock to
+                * force client to wait for the lock endlessly once
+                * the lock is enqueued -bzzz */
+               *flags |= LDLM_FL_NO_TIMEOUT;
        }
+       rc = LDLM_ITER_CONTINUE;
+
+out_rpc_list:
        RETURN(rc);
 }
 #endif /* HAVE_SERVER_SUPPORT */
@@ -1005,7 +965,7 @@ __u64 ldlm_extent_shift_kms(struct ldlm_lock *lock, __u64 old_kms)
 EXPORT_SYMBOL(ldlm_extent_shift_kms);
 
 struct kmem_cache *ldlm_interval_slab;
-struct ldlm_interval *ldlm_interval_alloc(struct ldlm_lock *lock)
+static struct ldlm_interval *ldlm_interval_alloc(struct ldlm_lock *lock)
 {
        struct ldlm_interval *node;
        ENTRY;
@@ -1059,13 +1019,20 @@ static inline int ldlm_mode_to_index(enum ldlm_mode mode)
        int index;
 
        LASSERT(mode != 0);
-       LASSERT(IS_PO2(mode));
-       for (index = -1; mode != 0; index++, mode >>= 1)
-               /* do nothing */;
+       LASSERT(is_power_of_2(mode));
+       index = ilog2(mode);
        LASSERT(index < LCK_MODE_NUM);
        return index;
 }
 
+int ldlm_extent_alloc_lock(struct ldlm_lock *lock)
+{
+       lock->l_tree_node = NULL;
+       if (ldlm_interval_alloc(lock) == NULL)
+               return -ENOMEM;
+       return 0;
+}
+
 /** Add newly granted lock into interval tree for the resource. */
 void ldlm_extent_add_lock(struct ldlm_resource *res,
                           struct ldlm_lock *lock)
@@ -1075,7 +1042,7 @@ void ldlm_extent_add_lock(struct ldlm_resource *res,
         struct ldlm_extent *extent;
        int idx, rc;
 
-        LASSERT(lock->l_granted_mode == lock->l_req_mode);
+       LASSERT(ldlm_is_granted(lock));
 
         node = lock->l_tree_node;
         LASSERT(node != NULL);