/*
 * Copyright (C) Red Hat  Inc., 2015
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library.
 *
 * ---------------------------------------
 */

/**
 * @file    fsal_up.c
 *
 * @author  Soumya Koduri <skoduri@redhat.com>
 *
 * @brief   Upcall Interface for FSAL_GLUSTER
 *
 */

#include "config.h"

#include "fsal.h"
#include "fsal_up.h"
#include "gluster_internal.h"
#include "fsal_convert.h"
#include <sys/types.h>
#include <unistd.h>
#include <utime.h>
#include <sys/time.h>
#include <urcu-bp.h>
#include "sal_functions.h"

int up_process_event_object(struct glusterfs_fs *gl_fs,
			    struct glfs_object *object,
			    enum glfs_upcall_reason reason)
{
	int	     rc                             = -1;
	glfs_t          *fs                         = NULL;
	char            vol_uuid[GLAPI_UUID_LENGTH] = {'\0'};
	unsigned char   globjhdl[GLAPI_HANDLE_LENGTH];
	struct gsh_buffdesc         key;
	const struct fsal_up_vector *event_func;
	fsal_status_t fsal_status = {0, 0};
#ifdef USE_GLUSTER_DELEGATION
	state_status_t rc_s;
#endif

	fs = gl_fs->fs;
	if (!fs) {
		LogCrit(COMPONENT_FSAL_UP,
			"Invalid fs object of the glusterfs_fs(%p)",
			 gl_fs);
		goto out;
	}

	rc = glfs_h_extract_handle(object, globjhdl+GLAPI_UUID_LENGTH,
				   GFAPI_HANDLE_LENGTH);
	if (rc < 0) {
		LogDebug(COMPONENT_FSAL_UP,
			 "glfs_h_extract_handle failed %p",
			 fs);
		goto out;
	}

	rc = glfs_get_volumeid(fs, vol_uuid,
			       GLAPI_UUID_LENGTH);
	if (rc < 0) {
		LogDebug(COMPONENT_FSAL_UP,
			 "glfs_get_volumeid failed %p",
			 fs);
		goto out;
	}

	memcpy(globjhdl, vol_uuid, GLAPI_UUID_LENGTH);
	key.addr = &globjhdl;
	key.len = GLAPI_HANDLE_LENGTH;

	LogDebug(COMPONENT_FSAL_UP, "Received event to process for %p",
		 fs);

	event_func = gl_fs->up_ops;


	switch (reason) {
	case GLFS_EVENT_INODE_INVALIDATE:
	fsal_status = event_func->invalidate_close(
					event_func,
					&key,
					FSAL_UP_INVALIDATE_CACHE);
		rc = fsal_status.major;
		if (FSAL_IS_ERROR(fsal_status) &&
			 fsal_status.major != ERR_FSAL_NOENT) {
			LogWarn(COMPONENT_FSAL_UP,
			"UP event:GLFS_EVENT_INODE_INVALIDATE could not be processed for fs (%p), rc(%d)",
			gl_fs->fs, rc);
		}
	break;
#ifdef USE_GLUSTER_DELEGATION
	case GLFS_EVENT_RECALL_LEASE:
		rc_s = event_func->delegrecall(event_func, &key);
		if (rc_s != STATE_SUCCESS) {
			LogWarn(COMPONENT_FSAL_UP,
			"UP event:GLFS_EVENT_RECALL_LEASE could not be processed for fs(%p), reason(%s)",
			gl_fs->fs, state_err_str(rc_s));
			rc = -1;
		}
	break;
#endif
	default:
		/* invalid reason */
		rc = EINVAL;
		LogWarn(COMPONENT_FSAL_UP,
			"UP event: Invalid value provided for fs(%p), event(%d)",
			gl_fs->fs, reason);
	}

out:
	return rc;
}

void *GLUSTERFSAL_UP_Thread(void *Arg)
{
	struct glusterfs_fs         *gl_fs              = Arg;
	struct fsal_up_vector *event_func;
	char                        thr_name[16];
	int                         rc                  = 0;
	struct glfs_upcall          *cbk                = NULL;
	enum glfs_upcall_reason     reason              = 0;
	int                         retry               = 0;
	int                         errsv               = 0;
	struct glfs_object          *object             = NULL;
	struct glfs_object          *p_object           = NULL;
	struct glfs_object          *oldp_object        = NULL;
	struct glfs_upcall_inode    *in_arg             = NULL;
#ifdef USE_GLUSTER_DELEGATION
	struct glfs_upcall_lease    *lease_arg          = NULL;
#endif

	rcu_register_thread();
	(void) snprintf(thr_name, sizeof(thr_name),
			"fsal_up_%p",
			gl_fs->fs);
	SetNameFunction(thr_name);

	/* Set the FSAL UP functions that will be used to process events. */
	event_func = (struct fsal_up_vector *)gl_fs->up_ops;

	if (event_func == NULL) {
		LogFatal(COMPONENT_FSAL_UP,
			 "FSAL up vector does not exist. Can not continue.");
		gsh_free(Arg);
		goto out;
	}

	LogFullDebug(COMPONENT_FSAL_UP,
		     "Initializing FSAL Callback context for %p.",
		     gl_fs->fs);

	if (!gl_fs->fs) {
		LogCrit(COMPONENT_FSAL_UP,
			"FSAL Callback interface - Null glfs context.");
		goto out;
	}

	/* wait for upcall readiness */
	up_ready_wait(event_func);

	/* Start querying for events and processing. */
	/** @todo : Do batch processing instead */
	while (!atomic_fetch_int8_t(&gl_fs->destroy_mode)) {
		LogFullDebug(COMPONENT_FSAL_UP,
			     "Requesting event from FSAL Callback interface for %p.",
			     gl_fs->fs);

		reason = 0;

		rc = glfs_h_poll_upcall(gl_fs->fs, &cbk);
		errsv = errno;

		if (rc != 0) {
			/* if ENOMEM retry for couple of times
			 * and then exit
			 */
			if ((errsv == ENOMEM) && (retry < 10)) {
				sleep(1);
				retry++;
				continue;
			} else {
				switch (errsv) {
				case ENOMEM:
					LogMajor(COMPONENT_FSAL_UP,
						 "Memory allocation failed during poll_upcall for (%p).",
						 gl_fs->fs);
					abort();

				case ENOTSUP:
					LogEvent(COMPONENT_FSAL_UP,
						 "Upcall feature is not supported for (%p).",
						 gl_fs->fs);
					break;
				default:
					LogCrit(COMPONENT_FSAL_UP,
						"Poll upcall failed for %p. rc %d errno %d (%s) reason %d",
						gl_fs->fs, rc, errsv,
						strerror(errsv), reason);
				}
				goto out;
			}
		}

		retry = 0;

		LogFullDebug(COMPONENT_FSAL_UP,
			     "Received upcall event: reason(%d)",
			     reason);

		if (!cbk) {
			usleep(gl_fs->up_poll_usec);
			continue;
		}

		reason = glfs_upcall_get_reason(cbk);
		/* Decide what type of event this is
		 * inode update / invalidate? */
		switch (reason) {
		case GLFS_UPCALL_EVENT_NULL:
			usleep(gl_fs->up_poll_usec);
			continue;
		case GLFS_UPCALL_INODE_INVALIDATE:
			in_arg = glfs_upcall_get_event(cbk);

			if (!in_arg) {
				/* Could be ENOMEM issues. continue */
				LogWarn(COMPONENT_FSAL_UP,
					"Received NULL upcall event arg");
				break;
			}

			object = glfs_upcall_inode_get_object(in_arg);
			if (object)
				up_process_event_object(gl_fs, object, reason);
			p_object = glfs_upcall_inode_get_pobject(in_arg);
			if (p_object)
				up_process_event_object(gl_fs, p_object,
							reason);
			oldp_object = glfs_upcall_inode_get_oldpobject(in_arg);
			if (oldp_object)
				up_process_event_object(gl_fs, oldp_object,
							reason);
			break;
#ifdef USE_GLUSTER_DELEGATION
		case GLFS_UPCALL_RECALL_LEASE:
			lease_arg = glfs_upcall_get_event(cbk);

			if (!lease_arg) {
				/* Could be ENOMEM issues. continue */
				LogWarn(COMPONENT_FSAL_UP,
					"Received NULL upcall event arg");
				break;
			}

			object = glfs_upcall_lease_get_object(lease_arg);
			if (object)
				up_process_event_object(gl_fs, object, reason);
			break;
#endif
		default:
			LogWarn(COMPONENT_FSAL_UP, "Unknown event: %d", reason);
			continue;
		}
		if (cbk) {
			glfs_free(cbk);
			cbk = NULL;
		}
	}

out:
	rcu_unregister_thread();
	return NULL;
}				/* GLUSTERFSFSAL_UP_Thread */

void gluster_process_upcall(struct glfs_upcall *cbk, void *data)
{
	struct glusterfs_fs         *gl_fs              = data;
	struct fsal_up_vector *event_func;
	enum glfs_upcall_reason     reason              = 0;
	struct glfs_object          *object             = NULL;
	struct glfs_object          *p_object           = NULL;
	struct glfs_object          *oldp_object        = NULL;
	struct glfs_upcall_inode    *in_arg             = NULL;
#ifdef USE_GLUSTER_DELEGATION
	struct glfs_upcall_lease    *lease_arg          = NULL;
#endif

	if (!cbk) {
		LogFatal(COMPONENT_FSAL_UP, "Upcall received with no data");
		return;
	}

	/* Set the FSAL UP functions that will be used to process events. */
	event_func = (struct fsal_up_vector *)gl_fs->up_ops;

	if (!event_func) {
		LogFatal(COMPONENT_FSAL_UP,
			 "FSAL up vector does not exist. Can not continue.");
		goto out;
	}

	if (!gl_fs->fs) {
		LogCrit(COMPONENT_FSAL_UP,
			"FSAL Callback interface - Null glfs context.");
		goto out;
	}

	/* wait for upcall readiness */
	up_ready_wait(event_func);

	reason = glfs_upcall_get_reason(cbk);

	/* Decide what type of event this is
	 * inode update / invalidate? */
	switch (reason) {
	case GLFS_UPCALL_INODE_INVALIDATE:
		in_arg = glfs_upcall_get_event(cbk);

		if (!in_arg) {
			/* Could be ENOMEM issues. continue */
			LogWarn(COMPONENT_FSAL_UP,
				"Received NULL upcall event arg");
			break;
		}

		object = glfs_upcall_inode_get_object(in_arg);
		if (object)
			up_process_event_object(gl_fs, object, reason);

		p_object = glfs_upcall_inode_get_pobject(in_arg);
		if (p_object)
			up_process_event_object(gl_fs, p_object, reason);

		oldp_object = glfs_upcall_inode_get_oldpobject(in_arg);
		if (oldp_object)
			up_process_event_object(gl_fs, oldp_object, reason);
		break;
#ifdef USE_GLUSTER_DELEGATION
	case GLFS_UPCALL_RECALL_LEASE:
		lease_arg = glfs_upcall_get_event(cbk);

		if (!lease_arg) {
			/* Could be ENOMEM issues. continue */
			LogWarn(COMPONENT_FSAL_UP,
				"Received NULL upcall event arg");
			break;
		}

		object = glfs_upcall_lease_get_object(lease_arg);
		if (object)
			up_process_event_object(gl_fs, object, reason);
		break;
#endif
	default:
		LogWarn(COMPONENT_FSAL_UP, "Unknown event: %d", reason);
	}

out:
	glfs_free(cbk);
}
