/*
   Unix SMB/CIFS implementation.

   POSIX NTVFS backend - oplock handling

   Copyright (C) Stefan Metzmacher 2008

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"
#include "lib/messaging/messaging.h"
#include "lib/messaging/irpc.h"
#include "vfs_posix.h"


struct pvfs_oplock {
	struct pvfs_file_handle *handle;
	struct pvfs_file *file;
	uint32_t level;
	struct messaging_context *msg_ctx;
};

/*
  receive oplock breaks and forward them to the client
*/
static void pvfs_oplock_break(struct pvfs_oplock *opl, uint8_t level)
{
	NTSTATUS status;
	struct pvfs_file *f = opl->file;
	struct pvfs_file_handle *h = opl->handle;
	struct pvfs_state *pvfs = h->pvfs;

	DEBUG(10,("pvfs_oplock_break: sending oplock break level %d for '%s' %p\n",
		level, h->name->original_name, h));
	status = ntvfs_send_oplock_break(pvfs->ntvfs, f->ntvfs, level);
	if (!NT_STATUS_IS_OK(status)) {
		DEBUG(0,("pvfs_oplock_break: sending oplock break failed: %s\n",
			nt_errstr(status)));
	}
}

static void pvfs_oplock_break_dispatch(struct messaging_context *msg,
				       void *private_data, uint32_t msg_type,
				       struct server_id src, DATA_BLOB *data)
{
	struct pvfs_oplock *opl = talloc_get_type(private_data,
						  struct pvfs_oplock);
	struct opendb_oplock_break opb;

	ZERO_STRUCT(opb);

	/* we need to check that this one is for us. See
	   messaging_send_ptr() for the other side of this.
	 */
	if (data->length == sizeof(struct opendb_oplock_break)) {
		struct opendb_oplock_break *p;
		p = (struct opendb_oplock_break *)data->data;
		opb = *p;
	} else {
		DEBUG(0,("%s: ignore oplock break with length[%u]\n",
			__location__, data->length));
		return;
	}
	if (opb.file_handle != opl->handle) {
		return;
	}

	/*
	 * maybe we should use ntvfs_setup_async()
	 */
	pvfs_oplock_break(opl, opb.level);
}

static int pvfs_oplock_destructor(struct pvfs_oplock *opl)
{
	messaging_deregister(opl->msg_ctx, MSG_NTVFS_OPLOCK_BREAK, opl);
	return 0;
}

NTSTATUS pvfs_setup_oplock(struct pvfs_file *f, uint32_t oplock_granted)
{
	NTSTATUS status;
	struct pvfs_oplock *opl;
	uint32_t level = OPLOCK_NONE;

	f->handle->oplock = NULL;

	switch (oplock_granted) {
	case EXCLUSIVE_OPLOCK_RETURN:
		level = OPLOCK_EXCLUSIVE;
		break;
	case BATCH_OPLOCK_RETURN:
		level = OPLOCK_BATCH;
		break;
	case LEVEL_II_OPLOCK_RETURN:
		level = OPLOCK_LEVEL_II;
		break;
	}

	if (level == OPLOCK_NONE) {
		return NT_STATUS_OK;
	}

	opl = talloc(f->handle, struct pvfs_oplock);
	NT_STATUS_HAVE_NO_MEMORY(opl);

	opl->handle	= f->handle;
	opl->file	= f;
	opl->level	= level;
	opl->msg_ctx	= f->pvfs->ntvfs->ctx->msg_ctx;

	status = messaging_register(opl->msg_ctx,
				    opl,
				    MSG_NTVFS_OPLOCK_BREAK,
				    pvfs_oplock_break_dispatch);
	NT_STATUS_NOT_OK_RETURN(status);

	/* destructor */
	talloc_set_destructor(opl, pvfs_oplock_destructor);

	f->handle->oplock = opl;

	return NT_STATUS_OK;
}