#include <linux/ceph/ceph_debug.h>

#include <linux/types.h>
#include <linux/slab.h>

#include <linux/ceph/cls_lock_client.h>
#include <linux/ceph/decode.h>

/**
 * ceph_cls_lock - grab rados lock for object
 * @oid, @oloc: object to lock
 * @lock_name: the name of the lock
 * @type: lock type (CEPH_CLS_LOCK_EXCLUSIVE or CEPH_CLS_LOCK_SHARED)
 * @cookie: user-defined identifier for this instance of the lock
 * @tag: user-defined tag
 * @desc: user-defined lock description
 * @flags: lock flags
 *
 * All operations on the same lock should use the same tag.
 */
int ceph_cls_lock(struct ceph_osd_client *osdc,
		  struct ceph_object_id *oid,
		  struct ceph_object_locator *oloc,
		  char *lock_name, u8 type, char *cookie,
		  char *tag, char *desc, u8 flags)
{
	int lock_op_buf_size;
	int name_len = strlen(lock_name);
	int cookie_len = strlen(cookie);
	int tag_len = strlen(tag);
	int desc_len = strlen(desc);
	void *p, *end;
	struct page *lock_op_page;
	struct timespec mtime;
	int ret;

	lock_op_buf_size = name_len + sizeof(__le32) +
			   cookie_len + sizeof(__le32) +
			   tag_len + sizeof(__le32) +
			   desc_len + sizeof(__le32) +
			   sizeof(struct ceph_timespec) +
			   /* flag and type */
			   sizeof(u8) + sizeof(u8) +
			   CEPH_ENCODING_START_BLK_LEN;
	if (lock_op_buf_size > PAGE_SIZE)
		return -E2BIG;

	lock_op_page = alloc_page(GFP_NOIO);
	if (!lock_op_page)
		return -ENOMEM;

	p = page_address(lock_op_page);
	end = p + lock_op_buf_size;

	/* encode cls_lock_lock_op struct */
	ceph_start_encoding(&p, 1, 1,
			    lock_op_buf_size - CEPH_ENCODING_START_BLK_LEN);
	ceph_encode_string(&p, end, lock_name, name_len);
	ceph_encode_8(&p, type);
	ceph_encode_string(&p, end, cookie, cookie_len);
	ceph_encode_string(&p, end, tag, tag_len);
	ceph_encode_string(&p, end, desc, desc_len);
	/* only support infinite duration */
	memset(&mtime, 0, sizeof(mtime));
	ceph_encode_timespec(p, &mtime);
	p += sizeof(struct ceph_timespec);
	ceph_encode_8(&p, flags);

	dout("%s lock_name %s type %d cookie %s tag %s desc %s flags 0x%x\n",
	     __func__, lock_name, type, cookie, tag, desc, flags);
	ret = ceph_osdc_call(osdc, oid, oloc, "lock", "lock",
			     CEPH_OSD_FLAG_WRITE, lock_op_page,
			     lock_op_buf_size, NULL, NULL);

	dout("%s: status %d\n", __func__, ret);
	__free_page(lock_op_page);
	return ret;
}
EXPORT_SYMBOL(ceph_cls_lock);

/**
 * ceph_cls_unlock - release rados lock for object
 * @oid, @oloc: object to lock
 * @lock_name: the name of the lock
 * @cookie: user-defined identifier for this instance of the lock
 */
int ceph_cls_unlock(struct ceph_osd_client *osdc,
		    struct ceph_object_id *oid,
		    struct ceph_object_locator *oloc,
		    char *lock_name, char *cookie)
{
	int unlock_op_buf_size;
	int name_len = strlen(lock_name);
	int cookie_len = strlen(cookie);
	void *p, *end;
	struct page *unlock_op_page;
	int ret;

	unlock_op_buf_size = name_len + sizeof(__le32) +
			     cookie_len + sizeof(__le32) +
			     CEPH_ENCODING_START_BLK_LEN;
	if (unlock_op_buf_size > PAGE_SIZE)
		return -E2BIG;

	unlock_op_page = alloc_page(GFP_NOIO);
	if (!unlock_op_page)
		return -ENOMEM;

	p = page_address(unlock_op_page);
	end = p + unlock_op_buf_size;

	/* encode cls_lock_unlock_op struct */
	ceph_start_encoding(&p, 1, 1,
			    unlock_op_buf_size - CEPH_ENCODING_START_BLK_LEN);
	ceph_encode_string(&p, end, lock_name, name_len);
	ceph_encode_string(&p, end, cookie, cookie_len);

	dout("%s lock_name %s cookie %s\n", __func__, lock_name, cookie);
	ret = ceph_osdc_call(osdc, oid, oloc, "lock", "unlock",
			     CEPH_OSD_FLAG_WRITE, unlock_op_page,
			     unlock_op_buf_size, NULL, NULL);

	dout("%s: status %d\n", __func__, ret);
	__free_page(unlock_op_page);
	return ret;
}
EXPORT_SYMBOL(ceph_cls_unlock);

/**
 * ceph_cls_break_lock - release rados lock for object for specified client
 * @oid, @oloc: object to lock
 * @lock_name: the name of the lock
 * @cookie: user-defined identifier for this instance of the lock
 * @locker: current lock owner
 */
int ceph_cls_break_lock(struct ceph_osd_client *osdc,
			struct ceph_object_id *oid,
			struct ceph_object_locator *oloc,
			char *lock_name, char *cookie,
			struct ceph_entity_name *locker)
{
	int break_op_buf_size;
	int name_len = strlen(lock_name);
	int cookie_len = strlen(cookie);
	struct page *break_op_page;
	void *p, *end;
	int ret;

	break_op_buf_size = name_len + sizeof(__le32) +
			    cookie_len + sizeof(__le32) +
			    sizeof(u8) + sizeof(__le64) +
			    CEPH_ENCODING_START_BLK_LEN;
	if (break_op_buf_size > PAGE_SIZE)
		return -E2BIG;

	break_op_page = alloc_page(GFP_NOIO);
	if (!break_op_page)
		return -ENOMEM;

	p = page_address(break_op_page);
	end = p + break_op_buf_size;

	/* encode cls_lock_break_op struct */
	ceph_start_encoding(&p, 1, 1,
			    break_op_buf_size - CEPH_ENCODING_START_BLK_LEN);
	ceph_encode_string(&p, end, lock_name, name_len);
	ceph_encode_copy(&p, locker, sizeof(*locker));
	ceph_encode_string(&p, end, cookie, cookie_len);

	dout("%s lock_name %s cookie %s locker %s%llu\n", __func__, lock_name,
	     cookie, ENTITY_NAME(*locker));
	ret = ceph_osdc_call(osdc, oid, oloc, "lock", "break_lock",
			     CEPH_OSD_FLAG_WRITE, break_op_page,
			     break_op_buf_size, NULL, NULL);

	dout("%s: status %d\n", __func__, ret);
	__free_page(break_op_page);
	return ret;
}
EXPORT_SYMBOL(ceph_cls_break_lock);

void ceph_free_lockers(struct ceph_locker *lockers, u32 num_lockers)
{
	int i;

	for (i = 0; i < num_lockers; i++)
		kfree(lockers[i].id.cookie);
	kfree(lockers);
}
EXPORT_SYMBOL(ceph_free_lockers);

static int decode_locker(void **p, void *end, struct ceph_locker *locker)
{
	u8 struct_v;
	u32 len;
	char *s;
	int ret;

	ret = ceph_start_decoding(p, end, 1, "locker_id_t", &struct_v, &len);
	if (ret)
		return ret;

	ceph_decode_copy(p, &locker->id.name, sizeof(locker->id.name));
	s = ceph_extract_encoded_string(p, end, NULL, GFP_NOIO);
	if (IS_ERR(s))
		return PTR_ERR(s);

	locker->id.cookie = s;

	ret = ceph_start_decoding(p, end, 1, "locker_info_t", &struct_v, &len);
	if (ret)
		return ret;

	*p += sizeof(struct ceph_timespec); /* skip expiration */
	ceph_decode_copy(p, &locker->info.addr, sizeof(locker->info.addr));
	ceph_decode_addr(&locker->info.addr);
	len = ceph_decode_32(p);
	*p += len; /* skip description */

	dout("%s %s%llu cookie %s addr %s\n", __func__,
	     ENTITY_NAME(locker->id.name), locker->id.cookie,
	     ceph_pr_addr(&locker->info.addr.in_addr));
	return 0;
}

static int decode_lockers(void **p, void *end, u8 *type, char **tag,
			  struct ceph_locker **lockers, u32 *num_lockers)
{
	u8 struct_v;
	u32 struct_len;
	char *s;
	int i;
	int ret;

	ret = ceph_start_decoding(p, end, 1, "cls_lock_get_info_reply",
				  &struct_v, &struct_len);
	if (ret)
		return ret;

	*num_lockers = ceph_decode_32(p);
	*lockers = kcalloc(*num_lockers, sizeof(**lockers), GFP_NOIO);
	if (!*lockers)
		return -ENOMEM;

	for (i = 0; i < *num_lockers; i++) {
		ret = decode_locker(p, end, *lockers + i);
		if (ret)
			goto err_free_lockers;
	}

	*type = ceph_decode_8(p);
	s = ceph_extract_encoded_string(p, end, NULL, GFP_NOIO);
	if (IS_ERR(s)) {
		ret = PTR_ERR(s);
		goto err_free_lockers;
	}

	*tag = s;
	return 0;

err_free_lockers:
	ceph_free_lockers(*lockers, *num_lockers);
	return ret;
}

/*
 * On success, the caller is responsible for:
 *
 *     kfree(tag);
 *     ceph_free_lockers(lockers, num_lockers);
 */
int ceph_cls_lock_info(struct ceph_osd_client *osdc,
		       struct ceph_object_id *oid,
		       struct ceph_object_locator *oloc,
		       char *lock_name, u8 *type, char **tag,
		       struct ceph_locker **lockers, u32 *num_lockers)
{
	int get_info_op_buf_size;
	int name_len = strlen(lock_name);
	struct page *get_info_op_page, *reply_page;
	size_t reply_len = PAGE_SIZE;
	void *p, *end;
	int ret;

	get_info_op_buf_size = name_len + sizeof(__le32) +
			       CEPH_ENCODING_START_BLK_LEN;
	if (get_info_op_buf_size > PAGE_SIZE)
		return -E2BIG;

	get_info_op_page = alloc_page(GFP_NOIO);
	if (!get_info_op_page)
		return -ENOMEM;

	reply_page = alloc_page(GFP_NOIO);
	if (!reply_page) {
		__free_page(get_info_op_page);
		return -ENOMEM;
	}

	p = page_address(get_info_op_page);
	end = p + get_info_op_buf_size;

	/* encode cls_lock_get_info_op struct */
	ceph_start_encoding(&p, 1, 1,
			    get_info_op_buf_size - CEPH_ENCODING_START_BLK_LEN);
	ceph_encode_string(&p, end, lock_name, name_len);

	dout("%s lock_name %s\n", __func__, lock_name);
	ret = ceph_osdc_call(osdc, oid, oloc, "lock", "get_info",
			     CEPH_OSD_FLAG_READ, get_info_op_page,
			     get_info_op_buf_size, reply_page, &reply_len);

	dout("%s: status %d\n", __func__, ret);
	if (ret >= 0) {
		p = page_address(reply_page);
		end = p + reply_len;

		ret = decode_lockers(&p, end, type, tag, lockers, num_lockers);
	}

	__free_page(get_info_op_page);
	__free_page(reply_page);
	return ret;
}
EXPORT_SYMBOL(ceph_cls_lock_info);