/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * 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 version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.gnu.org/licenses/gpl-2.0.html
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2011, 2017, Intel Corporation.
 *
 * Copyright 2016 Cray Inc, all rights reserved.
 * Author: Ben Evans.
 *
 * all fid manipulation functions go here
 *
 * FIDS are globally unique within a Lustre filessytem, and are made up
 * of three parts: sequence, Object ID, and version.
 *
 */
#ifndef _UAPI_LUSTRE_FID_H_
#define _UAPI_LUSTRE_FID_H_

#include <linux/types.h>
#include <linux/lustre/lustre_idl.h>

/** Special fid for root directory */
static const struct lu_fid LU_ROOT_FID = {
	.f_seq = FID_SEQ_ROOT,
	.f_oid = FID_OID_ROOT,
	.f_ver = 0x0000000000000000
};

/** Special fid for ".lustre" directory */
static const struct lu_fid LU_DOT_LUSTRE_FID = {
	.f_seq = FID_SEQ_DOT_LUSTRE,
	.f_oid = FID_OID_DOT_LUSTRE,
	.f_ver = 0x0000000000000000
};

/** Special fid for "fid" special object in .lustre */
static const struct lu_fid LU_OBF_FID = {
	.f_seq = FID_SEQ_DOT_LUSTRE,
	.f_oid = FID_OID_DOT_LUSTRE_OBF,
	.f_ver = 0x0000000000000000
};

/** returns fid object sequence */
static inline __u64 fid_seq(const struct lu_fid *fid)
{
	return fid->f_seq;
}

/** returns fid object id */
static inline __u32 fid_oid(const struct lu_fid *fid)
{
	return fid->f_oid;
}

/** returns fid object version */
static inline __u32 fid_ver(const struct lu_fid *fid)
{
	return fid->f_ver;
}

static inline void fid_zero(struct lu_fid *fid)
{
	memset(fid, 0, sizeof(*fid));
}

static inline __u64 fid_ver_oid(const struct lu_fid *fid)
{
	return (__u64)fid_ver(fid) << 32 | fid_oid(fid);
}

static inline bool fid_seq_is_mdt0(__u64 seq)
{
	return seq == FID_SEQ_OST_MDT0;
}

static inline bool fid_seq_is_mdt(__u64 seq)
{
	return seq == FID_SEQ_OST_MDT0 || seq >= FID_SEQ_NORMAL;
};

static inline bool fid_seq_is_echo(__u64 seq)
{
	return seq == FID_SEQ_ECHO;
}

static inline bool fid_is_echo(const struct lu_fid *fid)
{
	return fid_seq_is_echo(fid_seq(fid));
}

static inline bool fid_seq_is_llog(__u64 seq)
{
	return seq == FID_SEQ_LLOG;
}

static inline bool fid_is_llog(const struct lu_fid *fid)
{
	/* file with OID == 0 is not llog but contains last oid */
	return fid_seq_is_llog(fid_seq(fid)) && fid_oid(fid) > 0;
}

static inline bool fid_seq_is_rsvd(__u64 seq)
{
	return seq > FID_SEQ_OST_MDT0 && seq <= FID_SEQ_RSVD;
};

static inline bool fid_seq_is_special(__u64 seq)
{
	return seq == FID_SEQ_SPECIAL;
};

static inline bool fid_seq_is_local_file(__u64 seq)
{
	return seq == FID_SEQ_LOCAL_FILE ||
	       seq == FID_SEQ_LOCAL_NAME;
};

static inline bool fid_seq_is_root(__u64 seq)
{
	return seq == FID_SEQ_ROOT;
}

static inline bool fid_seq_is_dot(__u64 seq)
{
	return seq == FID_SEQ_DOT_LUSTRE;
}

static inline bool fid_seq_is_default(__u64 seq)
{
	return seq == FID_SEQ_LOV_DEFAULT;
}

static inline bool fid_is_mdt0(const struct lu_fid *fid)
{
	return fid_seq_is_mdt0(fid_seq(fid));
}

static inline void lu_root_fid(struct lu_fid *fid)
{
	fid->f_seq = FID_SEQ_ROOT;
	fid->f_oid = FID_OID_ROOT;
	fid->f_ver = 0;
}

static inline void lu_echo_root_fid(struct lu_fid *fid)
{
	fid->f_seq = FID_SEQ_ROOT;
	fid->f_oid = FID_OID_ECHO_ROOT;
	fid->f_ver = 0;
}

static inline void lu_update_log_fid(struct lu_fid *fid, __u32 index)
{
	fid->f_seq = FID_SEQ_UPDATE_LOG;
	fid->f_oid = index;
	fid->f_ver = 0;
}

static inline void lu_update_log_dir_fid(struct lu_fid *fid, __u32 index)
{
	fid->f_seq = FID_SEQ_UPDATE_LOG_DIR;
	fid->f_oid = index;
	fid->f_ver = 0;
}

/**
 * Check if a fid is igif or not.
 * \param fid the fid to be tested.
 * \return true if the fid is an igif; otherwise false.
 */
static inline bool fid_seq_is_igif(__u64 seq)
{
	return seq >= FID_SEQ_IGIF && seq <= FID_SEQ_IGIF_MAX;
}

static inline bool fid_is_igif(const struct lu_fid *fid)
{
	return fid_seq_is_igif(fid_seq(fid));
}

/**
 * Check if a fid is idif or not.
 * \param fid the fid to be tested.
 * \return true if the fid is an idif; otherwise false.
 */
static inline bool fid_seq_is_idif(__u64 seq)
{
	return seq >= FID_SEQ_IDIF && seq <= FID_SEQ_IDIF_MAX;
}

static inline bool fid_is_idif(const struct lu_fid *fid)
{
	return fid_seq_is_idif(fid_seq(fid));
}

static inline bool fid_is_local_file(const struct lu_fid *fid)
{
	return fid_seq_is_local_file(fid_seq(fid));
}

static inline bool fid_seq_is_norm(__u64 seq)
{
	return (seq >= FID_SEQ_NORMAL);
}

static inline bool fid_is_norm(const struct lu_fid *fid)
{
	return fid_seq_is_norm(fid_seq(fid));
}

static inline int fid_is_layout_rbtree(const struct lu_fid *fid)
{
	return fid_seq(fid) == FID_SEQ_LAYOUT_RBTREE;
}

static inline bool fid_seq_is_update_log(__u64 seq)
{
	return seq == FID_SEQ_UPDATE_LOG;
}

static inline bool fid_is_update_log(const struct lu_fid *fid)
{
	return fid_seq_is_update_log(fid_seq(fid));
}

static inline bool fid_seq_is_update_log_dir(__u64 seq)
{
	return seq == FID_SEQ_UPDATE_LOG_DIR;
}

static inline bool fid_is_update_log_dir(const struct lu_fid *fid)
{
	return fid_seq_is_update_log_dir(fid_seq(fid));
}

/* convert an OST objid into an IDIF FID SEQ number */
static inline __u64 fid_idif_seq(__u64 id, __u32 ost_idx)
{
	return FID_SEQ_IDIF | (ost_idx << 16) | ((id >> 32) & 0xffff);
}

/* convert a packed IDIF FID into an OST objid */
static inline __u64 fid_idif_id(__u64 seq, __u32 oid, __u32 ver)
{
	return ((__u64)ver << 48) | ((seq & 0xffff) << 32) | oid;
}

static inline __u32 idif_ost_idx(__u64 seq)
{
	return (seq >> 16) & 0xffff;
}

/* extract ost index from IDIF FID */
static inline __u32 fid_idif_ost_idx(const struct lu_fid *fid)
{
	return idif_ost_idx(fid_seq(fid));
}

/* Check whether the fid is for LAST_ID */
static inline bool fid_is_last_id(const struct lu_fid *fid)
{
	if (fid_oid(fid) != 0)
		return false;

	if (fid_is_idif(fid) && ((fid_seq(fid) & 0xFFFF) != 0))
		return false;

	if (fid_seq(fid) == FID_SEQ_UPDATE_LOG ||
	    fid_seq(fid) == FID_SEQ_UPDATE_LOG_DIR ||
	    fid_seq_is_igif(fid_seq(fid)))
		return false;

	return true;
}

/**
 * Get inode number from an igif.
 * \param fid an igif to get inode number from.
 * \return inode number for the igif.
 */
static inline __kernel_ino_t lu_igif_ino(const struct lu_fid *fid)
{
	return fid_seq(fid);
}

/**
 * Get inode generation from an igif.
 * \param fid an igif to get inode generation from.
 * \return inode generation for the igif.
 */
static inline __u32 lu_igif_gen(const struct lu_fid *fid)
{
	return fid_oid(fid);
}

/**
 * Build igif from the inode number/generation.
 */
static inline void lu_igif_build(struct lu_fid *fid, __u32 ino, __u32 gen)
{
	fid->f_seq = ino;
	fid->f_oid = gen;
	fid->f_ver = 0;
}

/*
 * Fids are transmitted across network (in the sender byte-ordering),
 * and stored on disk in big-endian order.
 */
static inline void fid_cpu_to_le(struct lu_fid *dst, const struct lu_fid *src)
{
	dst->f_seq = __cpu_to_le64(fid_seq(src));
	dst->f_oid = __cpu_to_le32(fid_oid(src));
	dst->f_ver = __cpu_to_le32(fid_ver(src));
}

static inline void fid_le_to_cpu(struct lu_fid *dst, const struct lu_fid *src)
{
	dst->f_seq = __le64_to_cpu(fid_seq(src));
	dst->f_oid = __le32_to_cpu(fid_oid(src));
	dst->f_ver = __le32_to_cpu(fid_ver(src));
}

static inline void fid_cpu_to_be(struct lu_fid *dst, const struct lu_fid *src)
{
	dst->f_seq = __cpu_to_be64(fid_seq(src));
	dst->f_oid = __cpu_to_be32(fid_oid(src));
	dst->f_ver = __cpu_to_be32(fid_ver(src));
}

static inline void fid_be_to_cpu(struct lu_fid *dst, const struct lu_fid *src)
{
	dst->f_seq = __be64_to_cpu(fid_seq(src));
	dst->f_oid = __be32_to_cpu(fid_oid(src));
	dst->f_ver = __be32_to_cpu(fid_ver(src));
}

static inline bool fid_is_sane(const struct lu_fid *fid)
{
	return fid && ((fid_seq(fid) >= FID_SEQ_START && !fid_ver(fid)) ||
			fid_is_igif(fid) || fid_is_idif(fid) ||
			fid_seq_is_rsvd(fid_seq(fid)));
}

static inline bool lu_fid_eq(const struct lu_fid *f0, const struct lu_fid *f1)
{
	return !memcmp(f0, f1, sizeof(*f0));
}

static inline int lu_fid_cmp(const struct lu_fid *f0,
			     const struct lu_fid *f1)
{
	if (fid_seq(f0) != fid_seq(f1))
		return fid_seq(f0) > fid_seq(f1) ? 1 : -1;

	if (fid_oid(f0) != fid_oid(f1))
		return fid_oid(f0) > fid_oid(f1) ? 1 : -1;

	if (fid_ver(f0) != fid_ver(f1))
		return fid_ver(f0) > fid_ver(f1) ? 1 : -1;

	return 0;
}

/**
 * Flatten 128-bit FID values into a 64-bit value for use as an inode number.
 * For non-IGIF FIDs this starts just over 2^32, and continues without
 * conflict until 2^64, at which point we wrap the high 24 bits of the SEQ
 * into the range where there may not be many OID values in use, to minimize
 * the risk of conflict.
 *
 * Suppose LUSTRE_SEQ_MAX_WIDTH less than (1 << 24) which is currently true,
 * the time between re-used inode numbers is very long - 2^40 SEQ numbers,
 * or about 2^40 client mounts, if clients create less than 2^24 files/mount.
 */
static inline __u64 fid_flatten64(const struct lu_fid *fid)
{
	__u64 ino;
	__u64 seq;

	if (fid_is_igif(fid)) {
		ino = lu_igif_ino(fid);
		return ino;
	}

	seq = fid_seq(fid);

	ino = (seq << 24) + ((seq >> 24) & 0xffffff0000ULL) + fid_oid(fid);

	return ino ?: fid_oid(fid);
}

/**
 * map fid to 32 bit value for ino on 32bit systems.
 */
static inline __u32 fid_flatten32(const struct lu_fid *fid)
{
	__u32 ino;
	__u64 seq;

	if (fid_is_igif(fid)) {
		ino = lu_igif_ino(fid);
		return ino;
	}

	seq = fid_seq(fid) - FID_SEQ_START;

	/* Map the high bits of the OID into higher bits of the inode number so
	 * that inodes generated at about the same time have a reduced chance
	 * of collisions. This will give a period of 2^12 = 1024 unique clients
	 * (from SEQ) and up to min(LUSTRE_SEQ_MAX_WIDTH, 2^20) = 128k objects
	 * (from OID), or up to 128M inodes without collisions for new files.
	 */
	ino = ((seq & 0x000fffffULL) << 12) + ((seq >> 8) & 0xfffff000) +
	      (seq >> (64 - (40-8)) & 0xffffff00) +
	      (fid_oid(fid) & 0xff000fff) + ((fid_oid(fid) & 0x00fff000) << 8);

	return ino ?: fid_oid(fid);
}

#if __BITS_PER_LONG == 32
#define fid_flatten_long fid_flatten32
#elif __BITS_PER_LONG == 64
#define fid_flatten_long fid_flatten64
#else
#error "Wordsize not 32 or 64"
#endif

#endif