// SPDX-License-Identifier: GPL-2.0

/*
 * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2012, 2015, Intel Corporation.
 */

/*
 * This file is part of Lustre, http://www.lustre.org/
 *
 * remote api for llog - client side
 *
 * Author: Andreas Dilger <adilger@clusterfs.com>
 */

#define DEBUG_SUBSYSTEM S_LOG

#include <linux/list.h>

#include <obd_class.h>
#include <lustre_log.h>
#include <lustre_net.h>

#include "ptlrpc_internal.h"

static struct obd_import *llog_client_entry(struct llog_ctxt *ctxt)
{
	struct obd_import *imp = ERR_PTR(-EINVAL);

	mutex_lock(&ctxt->loc_mutex);
	if (ctxt->loc_imp)
		imp = class_import_get(ctxt->loc_imp);
	else
		CWARN("%s: cannot finish recovery, ctxt #%d import not set, will retry rc = %ld\n",
		      ctxt->loc_obd ? ctxt->loc_obd->obd_name : "llog",
		      ctxt->loc_idx, PTR_ERR(imp));

	mutex_unlock(&ctxt->loc_mutex);
	return imp;
}

static void llog_client_exit(struct llog_ctxt *ctxt, struct obd_import *imp)
{
	mutex_lock(&ctxt->loc_mutex);
	if (ctxt->loc_imp != imp)
		CWARN("%s: import has changed from %p to %p\n",
		      ctxt->loc_obd ? ctxt->loc_obd->obd_name : "llog",
		      ctxt->loc_imp, imp);
	class_import_put(imp);
	mutex_unlock(&ctxt->loc_mutex);
}

/*
 * This is a callback from the llog_* functions.
 * Assumes caller has already pushed us into the kernel context.
 */
static int llog_client_open(const struct lu_env *env,
			    struct llog_handle *lgh, struct llog_logid *logid,
			    char *name, enum llog_open_param open_param)
{
	struct obd_import *imp;
	struct llogd_body *body;
	struct llog_ctxt *ctxt = lgh->lgh_ctxt;
	struct ptlrpc_request *req = NULL;
	char *tmp;
	int rc;

	ENTRY;

	imp = llog_client_entry(ctxt);
	if (IS_ERR(imp))
		return PTR_ERR(imp);

	/* client cannot create llog */
	LASSERTF(open_param != LLOG_OPEN_NEW, "%#x\n", open_param);
	LASSERT(lgh);

	req = ptlrpc_request_alloc(imp, &RQF_LLOG_ORIGIN_HANDLE_CREATE);
	if (!req)
		GOTO(out, rc = -ENOMEM);

	/* we have to set varlen name buffer even if name is not defined,
	 * to be able to set mdt_body buffer after */
	req_capsule_set_size(&req->rq_pill, &RMF_NAME, RCL_CLIENT,
			name ? strlen(name) + 1 : 1);

	rc = ptlrpc_request_pack(req, LUSTRE_LOG_VERSION,
				 LLOG_ORIGIN_HANDLE_CREATE);
	if (rc) {
		ptlrpc_request_free(req);
		req = NULL;
		GOTO(out, rc);
	}
	ptlrpc_request_set_replen(req);

	body = req_capsule_client_get(&req->rq_pill, &RMF_LLOGD_BODY);
	if (logid)
		body->lgd_logid = *logid;
	body->lgd_ctxt_idx = ctxt->loc_idx - 1;

	tmp = req_capsule_client_sized_get(&req->rq_pill, &RMF_NAME,
					   name ? strlen(name) + 1 : 1);
	LASSERT(tmp);
	if (name)
		strcpy(tmp, name);
	else
		tmp[0] = '\0';
	do_pack_body(req);

	rc = ptlrpc_queue_wait(req);
	if (rc)
		GOTO(out, rc);

	body = req_capsule_server_get(&req->rq_pill, &RMF_LLOGD_BODY);
	if (!body)
		GOTO(out, rc = -EFAULT);

	lgh->lgh_id = body->lgd_logid;
	lgh->lgh_ctxt = ctxt;
	EXIT;
out:
	llog_client_exit(ctxt, imp);
	ptlrpc_req_put(req);
	return rc;
}

static int llog_client_next_block(const struct lu_env *env,
				  struct llog_handle *loghandle,
				  int *cur_idx, int next_idx,
				  __u64 *cur_offset, void *buf, int len)
{
	struct obd_import *imp;
	struct ptlrpc_request *req = NULL;
	struct llogd_body *body;
	void *ptr;
	int rc;

	ENTRY;

	imp = llog_client_entry(loghandle->lgh_ctxt);
	if (IS_ERR(imp))
		return PTR_ERR(imp);

	req = ptlrpc_request_alloc_pack(imp, &RQF_LLOG_ORIGIN_HANDLE_NEXT_BLOCK,
					LUSTRE_LOG_VERSION,
					LLOG_ORIGIN_HANDLE_NEXT_BLOCK);
	if (IS_ERR(req))
		GOTO(err_exit, rc = PTR_ERR(req));

	body = req_capsule_client_get(&req->rq_pill, &RMF_LLOGD_BODY);
	body->lgd_logid = loghandle->lgh_id;
	body->lgd_ctxt_idx = loghandle->lgh_ctxt->loc_idx - 1;
	body->lgd_llh_flags = loghandle->lgh_hdr->llh_flags;
	body->lgd_index = next_idx;
	body->lgd_saved_index = *cur_idx;
	body->lgd_len = len;
	body->lgd_cur_offset = *cur_offset;

	req_capsule_set_size(&req->rq_pill, &RMF_EADATA, RCL_SERVER, len);
	ptlrpc_request_set_replen(req);
	rc = ptlrpc_queue_wait(req);
	/*
	 * -EBADR has a special meaning here. If llog_osd_next_block()
	 * reaches the end of the log without finding the desired
	 * record then it updates *cur_offset and *cur_idx and returns
	 * -EBADR. In llog_process_thread() we use this to detect
	 * EOF. But we must be careful to distinguish between -EBADR
	 * coming from llog_osd_next_block() and -EBADR coming from
	 * ptlrpc or below.
	 */
	if (rc == -EBADR) {
		if (!req->rq_repmsg ||
		    lustre_msg_get_status(req->rq_repmsg) != -EBADR)
			GOTO(out, rc);
	} else if (rc < 0) {
		GOTO(out, rc);
	}

	body = req_capsule_server_get(&req->rq_pill, &RMF_LLOGD_BODY);
	if (!body)
		GOTO(out, rc = -EFAULT);

	*cur_idx = body->lgd_saved_index;
	*cur_offset = body->lgd_cur_offset;

	if (rc < 0)
		GOTO(out, rc);

	/* The log records are swabbed as they are processed */
	ptr = req_capsule_server_get(&req->rq_pill, &RMF_EADATA);
	if (!ptr)
		GOTO(out, rc = -EFAULT);

	memcpy(buf, ptr, len);
	EXIT;
out:
	ptlrpc_req_put(req);
err_exit:
	llog_client_exit(loghandle->lgh_ctxt, imp);
	return rc;
}

static int llog_client_prev_block(const struct lu_env *env,
				  struct llog_handle *loghandle,
				  int prev_idx, void *buf, int len)
{
	struct obd_import *imp;
	struct ptlrpc_request *req = NULL;
	struct llogd_body *body;
	void *ptr;
	int rc;

	ENTRY;

	imp = llog_client_entry(loghandle->lgh_ctxt);
	if (IS_ERR(imp))
		return PTR_ERR(imp);

	req = ptlrpc_request_alloc_pack(imp, &RQF_LLOG_ORIGIN_HANDLE_PREV_BLOCK,
					LUSTRE_LOG_VERSION,
					LLOG_ORIGIN_HANDLE_PREV_BLOCK);
	if (IS_ERR(req))
		GOTO(err_exit, rc = PTR_ERR(req));

	body = req_capsule_client_get(&req->rq_pill, &RMF_LLOGD_BODY);
	body->lgd_logid = loghandle->lgh_id;
	body->lgd_ctxt_idx = loghandle->lgh_ctxt->loc_idx - 1;
	body->lgd_llh_flags = loghandle->lgh_hdr->llh_flags;
	body->lgd_index = prev_idx;
	body->lgd_len = len;

	req_capsule_set_size(&req->rq_pill, &RMF_EADATA, RCL_SERVER, len);
	ptlrpc_request_set_replen(req);

	rc = ptlrpc_queue_wait(req);
	if (rc)
		GOTO(out, rc);

	body = req_capsule_server_get(&req->rq_pill, &RMF_LLOGD_BODY);
	if (!body)
		GOTO(out, rc = -EFAULT);

	ptr = req_capsule_server_get(&req->rq_pill, &RMF_EADATA);
	if (!ptr)
		GOTO(out, rc = -EFAULT);

	memcpy(buf, ptr, len);
	EXIT;
out:
	ptlrpc_req_put(req);
err_exit:
	llog_client_exit(loghandle->lgh_ctxt, imp);
	return rc;
}

static int llog_client_read_header(const struct lu_env *env,
				   struct llog_handle *handle)
{
	struct obd_import *imp;
	struct ptlrpc_request *req = NULL;
	struct llogd_body *body;
	struct llog_log_hdr *hdr;
	struct llog_rec_hdr *llh_hdr;
	int rc;

	ENTRY;

	imp = llog_client_entry(handle->lgh_ctxt);
	if (IS_ERR(imp))
		return PTR_ERR(imp);

	req = ptlrpc_request_alloc_pack(imp,
					&RQF_LLOG_ORIGIN_HANDLE_READ_HEADER,
					LUSTRE_LOG_VERSION,
					LLOG_ORIGIN_HANDLE_READ_HEADER);
	if (IS_ERR(req))
		GOTO(err_exit, rc = PTR_ERR(req));

	body = req_capsule_client_get(&req->rq_pill, &RMF_LLOGD_BODY);
	body->lgd_logid = handle->lgh_id;
	body->lgd_ctxt_idx = handle->lgh_ctxt->loc_idx - 1;
	body->lgd_llh_flags = handle->lgh_hdr->llh_flags;

	ptlrpc_request_set_replen(req);
	rc = ptlrpc_queue_wait(req);
	if (rc)
		GOTO(out, rc);

	hdr = req_capsule_server_get(&req->rq_pill, &RMF_LLOG_LOG_HDR);
	if (!hdr)
		GOTO(out, rc = -EFAULT);

	if (handle->lgh_hdr_size < hdr->llh_hdr.lrh_len)
		GOTO(out, rc = -EFAULT);

	memcpy(handle->lgh_hdr, hdr, hdr->llh_hdr.lrh_len);
	handle->lgh_last_idx = LLOG_HDR_TAIL(handle->lgh_hdr)->lrt_index;

	/* sanity checks */
	llh_hdr = &handle->lgh_hdr->llh_hdr;
	if (llh_hdr->lrh_type != LLOG_HDR_MAGIC) {
		CERROR("bad log header magic: %#x (expecting %#x)\n",
		       llh_hdr->lrh_type, LLOG_HDR_MAGIC);
		rc = -EIO;
	} else if (llh_hdr->lrh_len !=
		   LLOG_HDR_TAIL(handle->lgh_hdr)->lrt_len ||
		   (llh_hdr->lrh_len & (llh_hdr->lrh_len - 1)) != 0 ||
		   llh_hdr->lrh_len < LLOG_MIN_CHUNK_SIZE ||
		   llh_hdr->lrh_len > handle->lgh_hdr_size) {
		CERROR("incorrectly sized log header: %#x, expecting %#x (power of two > 8192)\n",
		       llh_hdr->lrh_len,
		       LLOG_HDR_TAIL(handle->lgh_hdr)->lrt_len);
		CERROR("you may need to re-run lconf --write_conf.\n");
		rc = -EIO;
	}
	EXIT;
out:
	ptlrpc_req_put(req);
err_exit:
	llog_client_exit(handle->lgh_ctxt, imp);
	return rc;
}

static int llog_client_close(const struct lu_env *env,
			     struct llog_handle *handle)
{
	/*
	 * this doesn't call LLOG_ORIGIN_HANDLE_CLOSE because
	 * the servers all close the file at the end of every
	 * other LLOG_ RPC.
	 */
	return 0;
}

const struct llog_operations llog_client_ops = {
	.lop_next_block		= llog_client_next_block,
	.lop_prev_block		= llog_client_prev_block,
	.lop_read_header	= llog_client_read_header,
	.lop_open		= llog_client_open,
	.lop_close		= llog_client_close,
};
EXPORT_SYMBOL(llog_client_ops);
