struct list_head **insertp)
{
struct list_head *tmp;
- struct ldlm_lock *lock = req;
+ struct list_head *save = NULL;
+ struct ldlm_lock *lock = NULL;
ldlm_mode_t req_mode = req->l_req_mode;
int compat = 1;
+ int found = 0;
ENTRY;
lockmode_verify(req_mode);
- if (req->l_req_mode == LCK_GROUP) {
- int found = 0;
+ /* Extent locks are only queued once. We can get back here with
+ * insertp != NULL if the blocking ASTs returned -ERESTART. */
+ if (!list_empty(&req->l_res_link))
+ insertp = NULL;
- list_for_each(tmp, queue) {
- lock = list_entry(tmp, struct ldlm_lock, l_res_link);
- if (req == lock)
- break;
-
- if (lock->l_req_mode != LCK_GROUP) {
- /* group locks are not blocked by waiting PR|PW
- * locks. also, any group locks that could have
- * blocked us would have appeared before this
- * PR|PW lock in the list. */
- if (lock->l_req_mode != lock->l_granted_mode)
- break;
-
- compat = 0;
- if (!work_list)
- break;
-
- if (lock->l_blocking_ast)
- ldlm_add_ast_work_item(lock, req,
- work_list);
- continue;
- }
-
- /* no blocking ASTs are sent for group locks. */
-
- if (lock->l_policy_data.l_extent.gid !=
- req->l_policy_data.l_extent.gid) {
- if (*flags & LDLM_FL_BLOCK_NOWAIT)
- RETURN(-EWOULDBLOCK);
-
- compat = 0;
-
- /* there's a blocking group lock in front
- * of us on the queue. It can be held
- * indefinitely, so don't timeout. */
- *flags |= LDLM_FL_NO_TIMEOUT;
-
- /* the only reason to continue traversing the
- * list at this point is to find the proper
- * place to insert the lock in the waitq. */
- if (insertp && !found)
- continue;
-
- break;
- }
-
- /* if a group lock with this gid has already been
- * granted then grant this one. */
- if (lock->l_req_mode == lock->l_granted_mode) {
- compat = 2;
- break;
- }
- found = 1;
- }
- } else {
+ if (req->l_req_mode != LCK_GROUP) {
__u64 req_start = req->l_req_extent.start;
__u64 req_end = req->l_req_extent.end;
list_for_each(tmp, queue) {
lock = list_entry(tmp, struct ldlm_lock, l_res_link);
- if (req == lock) {
- tmp = tmp->next;
+ if (req == lock)
break;
- }
if (lock->l_req_mode == LCK_GROUP) {
if (*flags & LDLM_FL_BLOCK_NOWAIT)
/* there's a blocking group lock in front
* of us on the queue. It can be held
* indefinitely, so don't timeout. */
- *flags |= LDLM_FL_NO_TIMEOUT;
+ if (insertp) {
+ *flags |= LDLM_FL_NO_TIMEOUT;
+ /* lock_bitlock(req) is held here. */
+ req->l_flags |= LDLM_FL_NO_TIMEOUT;
+ }
if (work_list)
continue;
ldlm_add_ast_work_item(lock, req, work_list);
}
- /* Ensure we scan entire list if insertp is requested so that
- * the new request will be appended to the end of the list. */
- LASSERTF((insertp == NULL) || (tmp == queue) || (req == lock));
+ if (insertp)
+ *insertp = queue;
+
+ RETURN(compat);
+ }
+
+ list_for_each(tmp, queue) {
+ lock = list_entry(tmp, struct ldlm_lock, l_res_link);
+ if (req == lock)
+ break;
+
+ if (lock->l_req_mode != LCK_GROUP) {
+ if (lock->l_req_mode != lock->l_granted_mode) {
+ /* we must be traversing the waitq. */
+
+ /* If a group lock was already found then
+ * req can be queued before any extent locks
+ * that come after the found group lock. */
+ if (found)
+ break;
+
+ if (!insertp) {
+ /* We've hit a conflicting extent lock
+ * on the waitq before hitting the req
+ * group lock. See comments below. */
+ compat = 0;
+ break;
+ }
+
+ /* Group locks are not normally blocked by
+ * waiting PR|PW locks. */
+
+ /* If NO_TIMEOUT was sent back to the client
+ * we can queue the group lock in front of
+ * this extent lock. */
+ if (lock->l_flags & LDLM_FL_NO_TIMEOUT) {
+ if (save == NULL)
+ save = tmp;
+ continue;
+ }
+
+ /* If we did NOT send NO_TIMEOUT back to the
+ * client for this extent lock then the client
+ * could possibly timeout if we queue this
+ * group lock before it, so don't. This is the
+ * only way to get a conflicting extent lock
+ * in front of a group lock on the waitq. */
+ }
+
+ compat = 0;
+ if (!work_list) {
+ LASSERT(save == NULL);
+ break;
+ }
+
+ /* If we previously skipped over some extent locks
+ * because we thought we were going to queue the
+ * group lock in front of them then we need to go back
+ * and send blocking ASTs for the locks we skipped. */
+ if (save != NULL) {
+ struct ldlm_lock *lck2;
+
+ for (; save != tmp; save = save->next) {
+ lck2 = list_entry(save,
+ struct ldlm_lock,
+ l_res_link);
+
+ /* If there was a group lock after save
+ * then we would have exited this loop
+ * above. */
+ LASSERT(lck2->l_req_mode!=LCK_GROUP);
+
+ if (lck2->l_blocking_ast) {
+ ldlm_add_ast_work_item(lck2,req,
+ work_list);
+ }
+ }
+ save = NULL;
+ }
+
+ if (lock->l_blocking_ast)
+ ldlm_add_ast_work_item(lock, req, work_list);
+ continue;
+ }
+
+ /* If it was safe to insert a group lock at save,
+ * i.e. save != NULL, then this group lock already
+ * on the queue would have been inserted before save. */
+ LASSERT(save == NULL);
+
+ /* Note: no blocking ASTs are sent for group locks. */
+
+ if (lock->l_policy_data.l_extent.gid ==
+ req->l_policy_data.l_extent.gid) {
+ /* group locks with this gid already on the waitq. */
+ found = 2;
+
+ if (lock->l_req_mode == lock->l_granted_mode) {
+ /* if a group lock with this gid has already
+ * been granted then grant this one. */
+ compat = 2;
+ break;
+ }
+ } else {
+ if (found == 2)
+ break;
+
+ /* group locks already exist on the queue. */
+ found = 1;
+
+ if (*flags & LDLM_FL_BLOCK_NOWAIT)
+ RETURN(-EWOULDBLOCK);
+
+ compat = 0;
+
+ /* there's a blocking group lock in front
+ * of us on the queue. It can be held
+ * indefinitely, so don't timeout. */
+ *flags |= LDLM_FL_NO_TIMEOUT;
+
+ /* the only reason to continue traversing the
+ * list at this point is to find the proper
+ * place to insert the lock in the waitq. */
+ if (!insertp)
+ break;
+ }
}
- if (insertp)
- *insertp = tmp;
+ if (insertp != NULL) {
+ if (save != NULL)
+ *insertp = save;
+ else
+ *insertp = tmp;
+ }
RETURN(compat);
}
ldlm_resource_unlink_lock(lock);
ldlm_extent_policy(res, lock, flags);
+ lock_bitlock(lock);
+ lock->l_flags &= ~LDLM_FL_NO_TIMEOUT;
+ unlock_bitlock(lock);
ldlm_grant_lock(lock, work_list);
RETURN(LDLM_ITER_CONTINUE);
}
grant:
ldlm_extent_policy(res, lock, flags);
ldlm_resource_unlink_lock(lock);
+ lock->l_flags &= ~LDLM_FL_NO_TIMEOUT;
ldlm_grant_lock(lock, NULL);
} else {
/* If either of the compat_queue()s returned failure, then we
git://git.whamcloud.com / fs / lustre-release.git / blobdiff