-/* The purpose of this function is to return:
- * - the maximum extent
- * - containing the requested extent
- * - and not overlapping existing conflicting extents outside the requested one
- *
- * Use interval tree to expand the lock extent for granted lock.
- */
-static void ldlm_extent_internal_policy_granted(struct ldlm_lock *req,
- struct ldlm_extent *new_ex)
-{
- struct ldlm_resource *res = req->l_resource;
- ldlm_mode_t req_mode = req->l_req_mode;
- __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 };
- int conflicting = 0;
- int idx;
- ENTRY;
-
- lockmode_verify(req_mode);
-
- /* 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 };
-
- tree = &res->lr_itree[idx];
- if (lockmode_compat(tree->lit_mode, req_mode))
- continue;
-
- conflicting += tree->lit_size;
- if (conflicting > 4)
- limiter.start = req_start;
-
- if (interval_is_overlapped(tree->lit_root, &ext))
- CDEBUG(D_INFO,
- "req_mode = %d, tree->lit_mode = %d, "
- "tree->lit_size = %d\n",
- req_mode, tree->lit_mode, tree->lit_size);
- interval_expand(tree->lit_root, &ext, &limiter);
- limiter.start = max(limiter.start, ext.start);
- limiter.end = min(limiter.end, ext.end);
- if (limiter.start == req_start && limiter.end == req_end)
- break;
- }
-
- new_ex->start = limiter.start;
- new_ex->end = limiter.end;
- LASSERT(new_ex->start <= req_start);
- LASSERT(new_ex->end >= req_end);
-
- ldlm_extent_internal_policy_fixup(req, new_ex, conflicting);
- EXIT;
-}
-
-/* The purpose of this function is to return:
- * - the maximum extent
- * - containing the requested extent
- * - and not overlapping existing conflicting extents outside the requested one
- */
-static void
-ldlm_extent_internal_policy_waiting(struct ldlm_lock *req,
- struct ldlm_extent *new_ex)
-{
- cfs_list_t *tmp;
- struct ldlm_resource *res = req->l_resource;
- ldlm_mode_t req_mode = req->l_req_mode;
- __u64 req_start = req->l_req_extent.start;
- __u64 req_end = req->l_req_extent.end;
- int conflicting = 0;
- ENTRY;
-
- lockmode_verify(req_mode);
-
- /* for waiting locks */
- cfs_list_for_each(tmp, &res->lr_waiting) {
- struct ldlm_lock *lock;
- struct ldlm_extent *l_extent;
-
- lock = cfs_list_entry(tmp, struct ldlm_lock, l_res_link);
- l_extent = &lock->l_policy_data.l_extent;
-
- /* We already hit the minimum requested size, search no more */
- if (new_ex->start == req_start && new_ex->end == req_end) {
- EXIT;
- return;
- }
-
- /* Don't conflict with ourselves */
- if (req == lock)
- continue;
-
- /* Locks are compatible, overlap doesn't matter */
- /* Until bug 20 is fixed, try to avoid granting overlapping
- * locks on one client (they take a long time to cancel) */
- if (lockmode_compat(lock->l_req_mode, req_mode) &&
- lock->l_export != req->l_export)
- continue;
-
- /* If this is a high-traffic lock, don't grow downwards at all
- * or grow upwards too much */
- ++conflicting;
- if (conflicting > 4)
- new_ex->start = req_start;
-
- /* If lock doesn't overlap new_ex, skip it. */
- if (!ldlm_extent_overlap(l_extent, new_ex))
- continue;
-
- /* Locks conflicting in requested extents and we can't satisfy
- * both locks, so ignore it. Either we will ping-pong this
- * extent (we would regardless of what extent we granted) or
- * lock is unused and it shouldn't limit our extent growth. */
- if (ldlm_extent_overlap(&lock->l_req_extent,&req->l_req_extent))
- continue;
-
- /* We grow extents downwards only as far as they don't overlap
- * with already-granted locks, on the assumption that clients
- * will be writing beyond the initial requested end and would
- * then need to enqueue a new lock beyond previous request.
- * l_req_extent->end strictly < req_start, checked above. */
- if (l_extent->start < req_start && new_ex->start != req_start) {
- if (l_extent->end >= req_start)
- new_ex->start = req_start;
- else
- new_ex->start = min(l_extent->end+1, req_start);
- }
-
- /* If we need to cancel this lock anyways because our request
- * overlaps the granted lock, we grow up to its requested
- * extent start instead of limiting this extent, assuming that
- * clients are writing forwards and the lock had over grown
- * its extent downwards before we enqueued our request. */
- if (l_extent->end > req_end) {
- if (l_extent->start <= req_end)
- new_ex->end = max(lock->l_req_extent.start - 1,
- req_end);
- else
- new_ex->end = max(l_extent->start - 1, req_end);
- }
- }
-
- ldlm_extent_internal_policy_fixup(req, new_ex, conflicting);
- EXIT;
-}
-
-
-/* In order to determine the largest possible extent we can grant, we need
- * to scan all of the queues. */
-static void ldlm_extent_policy(struct ldlm_resource *res,
- struct ldlm_lock *lock, int *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;
-
- 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);
-
- 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;
- }
-}