#include <liblustre.h>
#endif
-static int
-ldlm_plain_compat_queue(struct list_head *queue, struct ldlm_lock *new,
- int send_cbs, int first_enq)
+#include "ldlm_internal.h"
+
+static inline int
+ldlm_plain_compat_queue(struct list_head *queue, struct ldlm_lock *req,
+ struct list_head *work_list)
{
- struct list_head *tmp, *pos;
- ldlm_mode_t mode = new->l_req_mode;
+ struct list_head *tmp;
+ struct ldlm_lock *lock;
+ ldlm_mode_t req_mode = req->l_req_mode;
int compat = 1;
ENTRY;
- list_for_each_safe(tmp, pos, queue) {
- struct ldlm_lock *old;
+ lockmode_verify(req_mode);
- old = list_entry(tmp, struct ldlm_lock, l_res_link);
- if (old == new)
- continue;
+ list_for_each(tmp, queue) {
+ lock = list_entry(tmp, struct ldlm_lock, l_res_link);
- if (lockmode_compat(old->l_req_mode, mode) &&
- lockmode_compat(old->l_granted_mode, mode)) {
- CDEBUG(D_OTHER, "lock modes are compatible, next.\n");
+ if (req == lock)
+ RETURN(compat);
+
+ if (lockmode_compat(lock->l_req_mode, req_mode))
continue;
- }
- compat = 0;
+ if (!work_list)
+ RETURN(0);
- /* if we're reprocessing the lock then the blocking ASTs
- * have already been sent. No need to continue. */
- if (!first_enq)
- break;
-
- if (send_cbs && (old->l_blocking_ast != NULL)) {
- CDEBUG(D_DLMTRACE, "lock %p incompatible; "
- "sending blocking AST.\n", old);
- ldlm_add_ast_work_item(old, new, NULL, 0);
- } else if (!(old->l_flags & LDLM_FL_LOCAL)) {
- CDEBUG(D_DLMTRACE, "lock %p incompatible; "
- "setting blocking AST.\n", old);
- old->l_flags |= LDLM_FL_AST_SENT;
- } else {
- CDEBUG(D_DLMTRACE, "local lock %p incompatible.\n",
- old);
- }
+ compat = 0;
+ if (lock->l_blocking_ast)
+ ldlm_add_ast_work_item(lock, req, work_list);
}
RETURN(compat);
}
-int
-ldlm_plain_enqueue(struct ldlm_lock **lockp, void *cookie, int *flags,
- int first_enq, ldlm_error_t *err)
+/* 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_plain_lock(struct ldlm_lock *lock, int *flags, int first_enq,
+ ldlm_error_t *err, struct list_head *work_list)
{
- struct ldlm_lock *lock = *lockp;
struct ldlm_resource *res = lock->l_resource;
- int convert_compat = 1;
- int waiting_compat = 1;
- int granted_compat = 1;
+ struct list_head rpc_list = LIST_HEAD_INIT(rpc_list);
+ int rc;
ENTRY;
- /* FIXME: We may want to optimize by checking lr_most_restr */
-
- /* On the first enqueue of this lock scan all of the queues
- * to set the LDLM_FL_AST_SENT flag in conflicting locks.
- * When the completion AST on the client side runs and sees
- * this flag is will set the LDLM_FL_CB_PENDING flag in the
- * lock so the client will know to cancel the lock as soon
- * as possible. This saves us from sending a blocking AST
- * in addition to the completion AST.
- *
- * If it's NOT the first enqueue of this lock then it must be
- * the first eligible lock in the queues because of the way that
- * ldlm_reprocess_all() works. So we don't have to check the
- * converting or waiting queues. */
- if (first_enq) {
- if (!list_empty(&res->lr_converting)) {
- convert_compat = 0;
- ldlm_plain_compat_queue(&res->lr_converting,
- lock, 0, first_enq);
- }
- if (!list_empty(&res->lr_waiting)) {
- waiting_compat = 0;
- ldlm_plain_compat_queue(&res->lr_waiting,
- lock, 0, first_enq);
- }
- }
- granted_compat =
- ldlm_plain_compat_queue(&res->lr_granted, lock, 1, first_enq);
-
- if (!convert_compat) {
- *flags |= LDLM_FL_BLOCK_CONV;
- RETURN(LDLM_ITER_STOP);
- }
- if (!waiting_compat) {
- *flags |= LDLM_FL_BLOCK_WAIT;
- RETURN(LDLM_ITER_STOP);
- }
- if (!granted_compat) {
- *flags |= LDLM_FL_BLOCK_GRANTED;
- RETURN(LDLM_ITER_STOP);
- }
+ LASSERT(list_empty(&res->lr_converting));
- list_del_init(&lock->l_res_link);
- ldlm_grant_lock(lock, NULL, 0);
+ if (!first_enq) {
+ LASSERT(work_list != NULL);
+ rc = ldlm_plain_compat_queue(&res->lr_granted, lock, NULL);
+ if (!rc)
+ RETURN(LDLM_ITER_STOP);
+ rc = ldlm_plain_compat_queue(&res->lr_waiting, lock, NULL);
+ if (!rc)
+ RETURN(LDLM_ITER_STOP);
- if (lock->l_flags & LDLM_FL_AST_SENT) {
- CDEBUG(D_DLMTRACE, "granted lock %p with AST set\n", lock);
- *flags |= (lock->l_flags & LDLM_FL_AST_SENT);
+ ldlm_resource_unlink_lock(lock);
+ ldlm_grant_lock(lock, work_list);
+ RETURN(LDLM_ITER_CONTINUE);
}
- RETURN(LDLM_ITER_CONTINUE);
+ restart:
+ rc = ldlm_plain_compat_queue(&res->lr_granted, lock, &rpc_list);
+ rc += ldlm_plain_compat_queue(&res->lr_waiting, lock, &rpc_list);
+
+ 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.
+ *
+ * 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_bl_ast_work(&rpc_list);
+ lock_res(res);
+ if (rc == -ERESTART)
+ GOTO(restart, -ERESTART);
+ *flags |= LDLM_FL_BLOCK_GRANTED;
+ } else {
+ ldlm_resource_unlink_lock(lock);
+ ldlm_grant_lock(lock, NULL);
+ }
+ RETURN(0);
}