Initial import

1 files changed, 314 insertions, 0 deletions

diff --git a/fs/dlm/ast.c b/fs/dlm/ast.c
new file mode 100644
index 000000000..dcea1e37a
--- /dev/null
+++ b/fs/dlm/ast.c
@@ -0,0 +1,314 @@
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2010 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#include "dlm_internal.h"
+#include "lock.h"
+#include "user.h"
+#include "ast.h"
+
+static uint64_t dlm_cb_seq;
+static DEFINE_SPINLOCK(dlm_cb_seq_spin);
+
+static void dlm_dump_lkb_callbacks(struct dlm_lkb *lkb)
+{
+	int i;
+
+	log_print("last_bast %x %llu flags %x mode %d sb %d %x",
+		  lkb->lkb_id,
+		  (unsigned long long)lkb->lkb_last_bast.seq,
+		  lkb->lkb_last_bast.flags,
+		  lkb->lkb_last_bast.mode,
+		  lkb->lkb_last_bast.sb_status,
+		  lkb->lkb_last_bast.sb_flags);
+
+	log_print("last_cast %x %llu flags %x mode %d sb %d %x",
+		  lkb->lkb_id,
+		  (unsigned long long)lkb->lkb_last_cast.seq,
+		  lkb->lkb_last_cast.flags,
+		  lkb->lkb_last_cast.mode,
+		  lkb->lkb_last_cast.sb_status,
+		  lkb->lkb_last_cast.sb_flags);
+
+	for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
+		log_print("cb %x %llu flags %x mode %d sb %d %x",
+			  lkb->lkb_id,
+			  (unsigned long long)lkb->lkb_callbacks[i].seq,
+			  lkb->lkb_callbacks[i].flags,
+			  lkb->lkb_callbacks[i].mode,
+			  lkb->lkb_callbacks[i].sb_status,
+			  lkb->lkb_callbacks[i].sb_flags);
+	}
+}
+
+int dlm_add_lkb_callback(struct dlm_lkb *lkb, uint32_t flags, int mode,
+			 int status, uint32_t sbflags, uint64_t seq)
+{
+	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
+	uint64_t prev_seq;
+	int prev_mode;
+	int i, rv;
+
+	for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
+		if (lkb->lkb_callbacks[i].seq)
+			continue;
+
+		/*
+		 * Suppress some redundant basts here, do more on removal.
+		 * Don't even add a bast if the callback just before it
+		 * is a bast for the same mode or a more restrictive mode.
+		 * (the addional > PR check is needed for PR/CW inversion)
+		 */
+
+		if ((i > 0) && (flags & DLM_CB_BAST) &&
+		    (lkb->lkb_callbacks[i-1].flags & DLM_CB_BAST)) {
+
+			prev_seq = lkb->lkb_callbacks[i-1].seq;
+			prev_mode = lkb->lkb_callbacks[i-1].mode;
+
+			if ((prev_mode == mode) ||
+			    (prev_mode > mode && prev_mode > DLM_LOCK_PR)) {
+
+				log_debug(ls, "skip %x add bast %llu mode %d "
+					  "for bast %llu mode %d",
+					  lkb->lkb_id,
+					  (unsigned long long)seq,
+					  mode,
+					  (unsigned long long)prev_seq,
+					  prev_mode);
+				rv = 0;
+				goto out;
+			}
+		}
+
+		lkb->lkb_callbacks[i].seq = seq;
+		lkb->lkb_callbacks[i].flags = flags;
+		lkb->lkb_callbacks[i].mode = mode;
+		lkb->lkb_callbacks[i].sb_status = status;
+		lkb->lkb_callbacks[i].sb_flags = (sbflags & 0x000000FF);
+		rv = 0;
+		break;
+	}
+
+	if (i == DLM_CALLBACKS_SIZE) {
+		log_error(ls, "no callbacks %x %llu flags %x mode %d sb %d %x",
+			  lkb->lkb_id, (unsigned long long)seq,
+			  flags, mode, status, sbflags);
+		dlm_dump_lkb_callbacks(lkb);
+		rv = -1;
+		goto out;
+	}
+ out:
+	return rv;
+}
+
+int dlm_rem_lkb_callback(struct dlm_ls *ls, struct dlm_lkb *lkb,
+			 struct dlm_callback *cb, int *resid)
+{
+	int i, rv;
+
+	*resid = 0;
+
+	if (!lkb->lkb_callbacks[0].seq) {
+		rv = -ENOENT;
+		goto out;
+	}
+
+	/* oldest undelivered cb is callbacks[0] */
+
+	memcpy(cb, &lkb->lkb_callbacks[0], sizeof(struct dlm_callback));
+	memset(&lkb->lkb_callbacks[0], 0, sizeof(struct dlm_callback));
+
+	/* shift others down */
+
+	for (i = 1; i < DLM_CALLBACKS_SIZE; i++) {
+		if (!lkb->lkb_callbacks[i].seq)
+			break;
+		memcpy(&lkb->lkb_callbacks[i-1], &lkb->lkb_callbacks[i],
+		       sizeof(struct dlm_callback));
+		memset(&lkb->lkb_callbacks[i], 0, sizeof(struct dlm_callback));
+		(*resid)++;
+	}
+
+	/* if cb is a bast, it should be skipped if the blocking mode is
+	   compatible with the last granted mode */
+
+	if ((cb->flags & DLM_CB_BAST) && lkb->lkb_last_cast.seq) {
+		if (dlm_modes_compat(cb->mode, lkb->lkb_last_cast.mode)) {
+			cb->flags |= DLM_CB_SKIP;
+
+			log_debug(ls, "skip %x bast %llu mode %d "
+				  "for cast %llu mode %d",
+				  lkb->lkb_id,
+				  (unsigned long long)cb->seq,
+				  cb->mode,
+				  (unsigned long long)lkb->lkb_last_cast.seq,
+				  lkb->lkb_last_cast.mode);
+			rv = 0;
+			goto out;
+		}
+	}
+
+	if (cb->flags & DLM_CB_CAST) {
+		memcpy(&lkb->lkb_last_cast, cb, sizeof(struct dlm_callback));
+		lkb->lkb_last_cast_time = ktime_get();
+	}
+
+	if (cb->flags & DLM_CB_BAST) {
+		memcpy(&lkb->lkb_last_bast, cb, sizeof(struct dlm_callback));
+		lkb->lkb_last_bast_time = ktime_get();
+	}
+	rv = 0;
+ out:
+	return rv;
+}
+
+void dlm_add_cb(struct dlm_lkb *lkb, uint32_t flags, int mode, int status,
+		uint32_t sbflags)
+{
+	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
+	uint64_t new_seq, prev_seq;
+	int rv;
+
+	spin_lock(&dlm_cb_seq_spin);
+	new_seq = ++dlm_cb_seq;
+	spin_unlock(&dlm_cb_seq_spin);
+
+	if (lkb->lkb_flags & DLM_IFL_USER) {
+		dlm_user_add_ast(lkb, flags, mode, status, sbflags, new_seq);
+		return;
+	}
+
+	mutex_lock(&lkb->lkb_cb_mutex);
+	prev_seq = lkb->lkb_callbacks[0].seq;
+
+	rv = dlm_add_lkb_callback(lkb, flags, mode, status, sbflags, new_seq);
+	if (rv < 0)
+		goto out;
+
+	if (!prev_seq) {
+		kref_get(&lkb->lkb_ref);
+
+		if (test_bit(LSFL_CB_DELAY, &ls->ls_flags)) {
+			mutex_lock(&ls->ls_cb_mutex);
+			list_add(&lkb->lkb_cb_list, &ls->ls_cb_delay);
+			mutex_unlock(&ls->ls_cb_mutex);
+		} else {
+			queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
+		}
+	}
+ out:
+	mutex_unlock(&lkb->lkb_cb_mutex);
+}
+
+void dlm_callback_work(struct work_struct *work)
+{
+	struct dlm_lkb *lkb = container_of(work, struct dlm_lkb, lkb_cb_work);
+	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
+	void (*castfn) (void *astparam);
+	void (*bastfn) (void *astparam, int mode);
+	struct dlm_callback callbacks[DLM_CALLBACKS_SIZE];
+	int i, rv, resid;
+
+	memset(&callbacks, 0, sizeof(callbacks));
+
+	mutex_lock(&lkb->lkb_cb_mutex);
+	if (!lkb->lkb_callbacks[0].seq) {
+		/* no callback work exists, shouldn't happen */
+		log_error(ls, "dlm_callback_work %x no work", lkb->lkb_id);
+		dlm_print_lkb(lkb);
+		dlm_dump_lkb_callbacks(lkb);
+	}
+
+	for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
+		rv = dlm_rem_lkb_callback(ls, lkb, &callbacks[i], &resid);
+		if (rv < 0)
+			break;
+	}
+
+	if (resid) {
+		/* cbs remain, loop should have removed all, shouldn't happen */
+		log_error(ls, "dlm_callback_work %x resid %d", lkb->lkb_id,
+			  resid);
+		dlm_print_lkb(lkb);
+		dlm_dump_lkb_callbacks(lkb);
+	}
+	mutex_unlock(&lkb->lkb_cb_mutex);
+
+	castfn = lkb->lkb_astfn;
+	bastfn = lkb->lkb_bastfn;
+
+	for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
+		if (!callbacks[i].seq)
+			break;
+		if (callbacks[i].flags & DLM_CB_SKIP) {
+			continue;
+		} else if (callbacks[i].flags & DLM_CB_BAST) {
+			bastfn(lkb->lkb_astparam, callbacks[i].mode);
+		} else if (callbacks[i].flags & DLM_CB_CAST) {
+			lkb->lkb_lksb->sb_status = callbacks[i].sb_status;
+			lkb->lkb_lksb->sb_flags = callbacks[i].sb_flags;
+			castfn(lkb->lkb_astparam);
+		}
+	}
+
+	/* undo kref_get from dlm_add_callback, may cause lkb to be freed */
+	dlm_put_lkb(lkb);
+}
+
+int dlm_callback_start(struct dlm_ls *ls)
+{
+	ls->ls_callback_wq = alloc_workqueue("dlm_callback",
+					     WQ_UNBOUND | WQ_MEM_RECLAIM, 0);
+	if (!ls->ls_callback_wq) {
+		log_print("can't start dlm_callback workqueue");
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+void dlm_callback_stop(struct dlm_ls *ls)
+{
+	if (ls->ls_callback_wq)
+		destroy_workqueue(ls->ls_callback_wq);
+}
+
+void dlm_callback_suspend(struct dlm_ls *ls)
+{
+	set_bit(LSFL_CB_DELAY, &ls->ls_flags);
+
+	if (ls->ls_callback_wq)
+		flush_workqueue(ls->ls_callback_wq);
+}
+
+void dlm_callback_resume(struct dlm_ls *ls)
+{
+	struct dlm_lkb *lkb, *safe;
+	int count = 0;
+
+	clear_bit(LSFL_CB_DELAY, &ls->ls_flags);
+
+	if (!ls->ls_callback_wq)
+		return;
+
+	mutex_lock(&ls->ls_cb_mutex);
+	list_for_each_entry_safe(lkb, safe, &ls->ls_cb_delay, lkb_cb_list) {
+		list_del_init(&lkb->lkb_cb_list);
+		queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
+		count++;
+	}
+	mutex_unlock(&ls->ls_cb_mutex);
+
+	if (count)
+		log_rinfo(ls, "dlm_callback_resume %d", count);
+}
+