/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
* vim:expandtab:shiftwidth=8:tabstop=8:
*
- * Copyright (c) 2002 Cluster File Systems, Inc.
+ * Copyright (c) 2002, 2003 Cluster File Systems, Inc.
* Author: Peter Braam <braam@clusterfs.com>
* Author: Phil Schwan <phil@clusterfs.com>
*
#include <linux/obd_support.h>
#include <linux/lustre_lib.h>
-/* This function will be called to judge if one extent overlaps with another */
-int ldlm_extent_compat(struct ldlm_lock *a, struct ldlm_lock *b)
-{
- if ((a->l_extent.start <= b->l_extent.end) &&
- (a->l_extent.end >= b->l_extent.start))
- RETURN(0);
-
- RETURN(1);
-}
-
#include "ldlm_internal.h"
/* The purpose of this function is to return:
* - containing the requested extent
* - and not overlapping existing conflicting extents outside the requested one
*
- * An alternative policy is to not shrink the new extent when conflicts exist.
- *
- * To reconstruct our formulas, take a deep breath. */
-static void policy_internal(struct list_head *queue, struct ldlm_extent *req_ex,
- struct ldlm_extent *new_ex, ldlm_mode_t mode)
+ * An alternative policy is to not shrink the new extent when conflicts exist */
+static void
+ldlm_extent_internal_policy(struct list_head *queue, struct ldlm_lock *req,
+ struct ldlm_extent *new_ex)
{
struct list_head *tmp;
+ ldlm_mode_t req_mode = req->l_req_mode;
+ __u64 req_start = req->l_policy_data.l_extent.start;
+ __u64 req_end = req->l_policy_data.l_extent.end;
+ ENTRY;
+
+ if (new_ex->start == req_start && new_ex->end == req_end) {
+ EXIT;
+ return;
+ }
list_for_each(tmp, queue) {
struct ldlm_lock *lock;
lock = list_entry(tmp, struct ldlm_lock, l_res_link);
+ if (req == lock) {
+ EXIT;
+ return;
+ }
+
/* if lock doesn't overlap new_ex, skip it. */
- if (lock->l_extent.end < new_ex->start ||
- lock->l_extent.start > new_ex->end)
+ if (lock->l_policy_data.l_extent.end < new_ex->start ||
+ lock->l_policy_data.l_extent.start > new_ex->end)
continue;
/* Locks are compatible, overlap doesn't matter */
- if (lockmode_compat(lock->l_req_mode, mode))
+ if (lockmode_compat(lock->l_req_mode, req_mode))
continue;
- if (lock->l_extent.start < req_ex->start) {
- if (lock->l_extent.end == ~0) {
- new_ex->start = req_ex->start;
- new_ex->end = req_ex->end;
+ if (lock->l_policy_data.l_extent.start < req_start) {
+ if (lock->l_policy_data.l_extent.end == ~0) {
+ new_ex->start = req_start;
+ new_ex->end = req_end;
+ EXIT;
return;
}
- new_ex->start = MIN(lock->l_extent.end + 1,
- req_ex->start);
+ new_ex->start = MIN(lock->l_policy_data.l_extent.end+1,
+ req_start);
}
- if (lock->l_extent.end > req_ex->end) {
- if (lock->l_extent.start == 0) {
- new_ex->start = req_ex->start;
- new_ex->end = req_ex->end;
+ if (lock->l_policy_data.l_extent.end > req_end) {
+ if (lock->l_policy_data.l_extent.start == 0) {
+ new_ex->start = req_start;
+ new_ex->end = req_end;
+ EXIT;
return;
}
- new_ex->end = MAX(lock->l_extent.start - 1,
- req_ex->end);
+ new_ex->end = MAX(lock->l_policy_data.l_extent.start-1,
+ req_end);
}
}
+ EXIT;
+}
+
+/* Determine if the lock is compatible with all locks on the queue. */
+static int
+ldlm_extent_compat_queue(struct list_head *queue, struct ldlm_lock *req,
+ int send_cbs)
+{
+ struct list_head *tmp;
+ struct ldlm_lock *lock;
+ ldlm_mode_t req_mode = req->l_req_mode;
+ __u64 req_start = req->l_policy_data.l_extent.start;
+ __u64 req_end = req->l_policy_data.l_extent.end;
+ int compat = 1;
+ ENTRY;
+
+ list_for_each(tmp, queue) {
+ lock = list_entry(tmp, struct ldlm_lock, l_res_link);
+
+ if (req == lock)
+ RETURN(compat);
+
+ /* locks are compatible, overlap doesn't matter */
+ if (lockmode_compat(lock->l_req_mode, req_mode))
+ continue;
+
+ /* if lock doesn't overlap skip it */
+ if (lock->l_policy_data.l_extent.end < req_start ||
+ lock->l_policy_data.l_extent.start > req_end)
+ continue;
+
+ if (!send_cbs)
+ RETURN(0);
+
+ compat = 0;
+ if (lock->l_blocking_ast)
+ ldlm_add_ast_work_item(lock, req, NULL, 0);
+ }
+
+ RETURN(compat);
}
-/* apply the internal policy by walking all the lists */
-int ldlm_extent_policy(struct ldlm_namespace *ns, struct ldlm_lock **lockp,
- void *req_cookie, ldlm_mode_t mode, int flags,
- void *data)
+/* If first_enq is 0 (ie, called from ldlm_reprocess_queue):
+ * - blocking ASTs have already been sent
+ * - the caller has already initialized req->lr_tmp
+ * - must call this function with the ns lock held
+ *
+ * If first_enq is 1 (ie, called from ldlm_lock_enqueue):
+ * - blocking ASTs have not been sent
+ * - the caller has NOT initialized req->lr_tmp, so we must
+ * - must call this function with the ns lock held once */
+int ldlm_process_extent_lock(struct ldlm_lock *lock, int *flags, int first_enq,
+ ldlm_error_t *err)
{
- struct ldlm_lock *lock = *lockp;
struct ldlm_resource *res = lock->l_resource;
- struct ldlm_extent *req_ex = req_cookie;
- struct ldlm_extent new_ex;
- new_ex.start = 0;
- new_ex.end = ~0;
-
- if (!res)
- LBUG();
-
- l_lock(&ns->ns_lock);
- policy_internal(&res->lr_granted, req_ex, &new_ex, mode);
- policy_internal(&res->lr_converting, req_ex, &new_ex, mode);
- policy_internal(&res->lr_waiting, req_ex, &new_ex, mode);
- l_unlock(&ns->ns_lock);
-
- memcpy(&lock->l_extent, &new_ex, sizeof(new_ex));
-
- LDLM_DEBUG(lock, "requested extent ["LPU64"->"LPU64"], new extent ["
- LPU64"->"LPU64"]",
- req_ex->start, req_ex->end, new_ex.start, new_ex.end);
-
- if (new_ex.end != req_ex->end || new_ex.start != req_ex->start)
- return ELDLM_LOCK_CHANGED;
- else
- return 0;
+ struct ldlm_extent new_ex = {0, ~0};
+ struct list_head rpc_list = LIST_HEAD_INIT(rpc_list);
+ int rc;
+ ENTRY;
+
+ LASSERT(list_empty(&res->lr_converting));
+
+ if (!first_enq) {
+ LASSERT(res->lr_tmp != NULL);
+ rc = ldlm_extent_compat_queue(&res->lr_granted, lock, 0);
+ if (!rc)
+ RETURN(LDLM_ITER_STOP);
+ rc = ldlm_extent_compat_queue(&res->lr_waiting, lock, 0);
+ if (!rc)
+ RETURN(LDLM_ITER_STOP);
+
+ ldlm_resource_unlink_lock(lock);
+ ldlm_grant_lock(lock, NULL, 0, 1);
+ RETURN(LDLM_ITER_CONTINUE);
+ }
+
+ /* In order to determine the largest possible extent we can
+ * grant, we need to scan all of the queues. */
+ ldlm_extent_internal_policy(&res->lr_granted, lock, &new_ex);
+ ldlm_extent_internal_policy(&res->lr_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;
+ }
+
+ restart:
+ LASSERT(res->lr_tmp == NULL);
+ res->lr_tmp = &rpc_list;
+ rc = ldlm_extent_compat_queue(&res->lr_granted, lock, 1);
+ rc += ldlm_extent_compat_queue(&res->lr_waiting, lock, 1);
+ res->lr_tmp = NULL;
+
+ if (rc != 2) {
+ /* If either of the compat_queue()s returned 0, then we
+ * have ASTs to send and must go onto the waiting list. */
+ ldlm_resource_unlink_lock(lock);
+ ldlm_resource_add_lock(res, &res->lr_waiting, lock);
+ l_unlock(&res->lr_namespace->ns_lock);
+ rc = ldlm_run_ast_work(res->lr_namespace, &rpc_list);
+ l_lock(&res->lr_namespace->ns_lock);
+ if (rc == -ERESTART)
+ GOTO(restart, -ERESTART);
+ *flags |= LDLM_FL_BLOCK_GRANTED;
+ } else {
+ ldlm_resource_unlink_lock(lock);
+ ldlm_grant_lock(lock, NULL, 0, 0);
+ }
+ RETURN(0);
}
git://git.whamcloud.com / fs / lustre-release.git / blobdiff