[firefly-linux-kernel-4.4.55.git] / drivers / staging / lustre / lustre / include / lustre_fid.h

/*
 * 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.sun.com/software/products/lustre/docs/GPLv2.pdf
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2011, 2012, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 *
 * lustre/include/lustre_fid.h
 *
 * Author: Yury Umanets <umka@clusterfs.com>
 */

#ifndef __LUSTRE_FID_H
#define __LUSTRE_FID_H

/** \defgroup fid fid
 *
 * @{
 *
 * http://wiki.lustre.org/index.php/Architecture_-_Interoperability_fids_zfs
 * describes the FID namespace and interoperability requirements for FIDs.
 * The important parts of that document are included here for reference.
 *
 * FID
 *   File IDentifier generated by client from range allocated by the SEQuence
 *   service and stored in struct lu_fid. The FID is composed of three parts:
 *   SEQuence, ObjectID, and VERsion.  The SEQ component is a filesystem
 *   unique 64-bit integer, and only one client is ever assigned any SEQ value.
 *   The first 0x400 FID_SEQ_NORMAL [2^33, 2^33 + 0x400] values are reserved
 *   for system use.  The OID component is a 32-bit value generated by the
 *   client on a per-SEQ basis to allow creating many unique FIDs without
 *   communication with the server.  The VER component is a 32-bit value that
 *   distinguishes between different FID instantiations, such as snapshots or
 *   separate subtrees within the filesystem.  FIDs with the same VER field
 *   are considered part of the same namespace.
 *
 * OLD filesystems are those upgraded from Lustre 1.x that predate FIDs, and
 *   MDTs use 32-bit ldiskfs internal inode/generation numbers (IGIFs), while
 *   OSTs use 64-bit Lustre object IDs and generation numbers.
 *
 * NEW filesystems are those formatted since the introduction of FIDs.
 *
 * IGIF
 *   Inode and Generation In FID, a surrogate FID used to globally identify
 *   an existing object on OLD formatted MDT file system. This would only be
 *   used on MDT0 in a DNE filesystem, because there cannot be more than one
 *   MDT in an OLD formatted filesystem. Belongs to sequence in [12, 2^32 - 1]
 *   range, where inode number is stored in SEQ, and inode generation is in OID.
 *   NOTE: This assumes no more than 2^32-1 inodes exist in the MDT filesystem,
 *   which is the maximum possible for an ldiskfs backend.  It also assumes
 *   that the reserved ext3/ext4/ldiskfs inode numbers [0-11] are never visible
 *   to clients, which has always been true.
 *
 * IDIF
 *   object ID In FID, a surrogate FID used to globally identify an existing
 *   OST object on OLD formatted OST file system. Belongs to a sequence in
 *   [2^32, 2^33 - 1]. Sequence number is calculated as:
 *
 *      1 << 32 | (ost_index << 16) | ((objid >> 32) & 0xffff)
 *
 *   that is, SEQ consists of 16-bit OST index, and higher 16 bits of object
 *   ID. The generation of unique SEQ values per OST allows the IDIF FIDs to
 *   be identified in the FLD correctly. The OID field is calculated as:
 *
 *      objid & 0xffffffff
 *
 *   that is, it consists of lower 32 bits of object ID.  For objects within
 *   the IDIF range, object ID extraction will be:
 *
 *      o_id = (fid->f_seq & 0x7fff) << 16 | fid->f_oid;
 *      o_seq = 0;  // formerly group number
 *
 *   NOTE: This assumes that no more than 2^48-1 objects have ever been created
 *   on any OST, and that no more than 65535 OSTs are in use.  Both are very
 *   reasonable assumptions, i.e. an IDIF can uniquely map all objects assuming
 *   a maximum creation rate of 1M objects per second for a maximum of 9 years,
 *   or combinations thereof.
 *
 * OST_MDT0
 *   Surrogate FID used to identify an existing object on OLD formatted OST
 *   filesystem. Belongs to the reserved SEQuence 0, and is used prior to
 *   the introduction of FID-on-OST, at which point IDIF will be used to
 *   identify objects as residing on a specific OST.
 *
 * LLOG
 *   For Lustre Log objects the object sequence 1 is used. This is compatible
 *   with both OLD and NEW namespaces, as this SEQ number is in the
 *   ext3/ldiskfs reserved inode range and does not conflict with IGIF
 *   sequence numbers.
 *
 * ECHO
 *   For testing OST IO performance the object sequence 2 is used. This is
 *   compatible with both OLD and NEW namespaces, as this SEQ number is in
 *   the ext3/ldiskfs reserved inode range and does not conflict with IGIF
 *   sequence numbers.
 *
 * OST_MDT1 .. OST_MAX
 *   For testing with multiple MDTs the object sequence 3 through 9 is used,
 *   allowing direct mapping of MDTs 1 through 7 respectively, for a total
 *   of 8 MDTs including OST_MDT0. This matches the legacy CMD project "group"
 *   mappings. However, this SEQ range is only for testing prior to any
 *   production DNE release, as the objects in this range conflict across all
 *   OSTs, as the OST index is not part of the FID.  For production DNE usage,
 *   OST objects created by MDT1+ will use FID_SEQ_NORMAL FIDs.
 *
 * DLM OST objid to IDIF mapping
 *   For compatibility with existing OLD OST network protocol structures, the
 *   FID must map onto the o_id and o_seq in a manner that ensures existing
 *   objects are identified consistently for IO, as well as onto the LDLM
 *   namespace to ensure IDIFs there is only a single resource name for any
 *   object in the DLM.  The OLD OST object DLM resource mapping is:
 *
 *      resource[] = {o_id, o_seq, 0, 0}; // o_seq == 0 for production releases
 *
 *   The NEW OST object DLM resource mapping is the same for both MDT and OST:
 *
 *      resource[] = {SEQ, OID, VER, HASH};
 *
 *  NOTE: for mapping IDIF values to DLM resource names the o_id may be
 *  larger than the 2^33 reserved sequence numbers for IDIF, so it is possible
 *  for the o_id numbers to overlap FID SEQ numbers in the resource. However,
 *  in all production releases the OLD o_seq field is always zero, and all
 *  valid FID OID values are non-zero, so the lock resources will not collide.
 *  Even so, the MDT and OST resources are also in different LDLM namespaces.
 */

#include "../../include/linux/libcfs/libcfs.h"
#include "lustre/lustre_idl.h"

struct lu_env;
struct lu_site;
struct lu_context;
struct obd_device;
struct obd_export;

/* Whole sequences space range and zero range definitions */
extern const struct lu_seq_range LUSTRE_SEQ_SPACE_RANGE;
extern const struct lu_seq_range LUSTRE_SEQ_ZERO_RANGE;
extern const struct lu_fid LUSTRE_BFL_FID;
extern const struct lu_fid LU_OBF_FID;
extern const struct lu_fid LU_DOT_LUSTRE_FID;

enum {
        /*
         * This is how may metadata FIDs may be allocated in one sequence(128k)
         */
        LUSTRE_METADATA_SEQ_MAX_WIDTH = 0x0000000000020000ULL,

        /*
         * This is how many data FIDs could be allocated in one sequence(4B - 1)
         */
        LUSTRE_DATA_SEQ_MAX_WIDTH = 0x00000000FFFFFFFFULL,

        /*
         * How many sequences to allocate to a client at once.
         */
        LUSTRE_SEQ_META_WIDTH = 0x0000000000000001ULL,

        /*
         * seq allocation pool size.
         */
        LUSTRE_SEQ_BATCH_WIDTH = LUSTRE_SEQ_META_WIDTH * 1000,

        /*
         * This is how many sequences may be in one super-sequence allocated to
         * MDTs.
         */
        LUSTRE_SEQ_SUPER_WIDTH = ((1ULL << 30ULL) * LUSTRE_SEQ_META_WIDTH)
};

enum {
        /** 2^6 FIDs for OI containers */
        OSD_OI_FID_OID_BITS     = 6,
        /** reserve enough FIDs in case we want more in the future */
        OSD_OI_FID_OID_BITS_MAX = 10,
};

/** special OID for local objects */
enum local_oid {
        /** \see fld_mod_init */
        FLD_INDEX_OID           = 3UL,
        /** \see fid_mod_init */
        FID_SEQ_CTL_OID         = 4UL,
        FID_SEQ_SRV_OID         = 5UL,
        /** \see mdd_mod_init */
        MDD_ROOT_INDEX_OID      = 6UL, /* deprecated in 2.4 */
        MDD_ORPHAN_OID          = 7UL, /* deprecated in 2.4 */
        MDD_LOV_OBJ_OID         = 8UL,
        MDD_CAPA_KEYS_OID       = 9UL,
        /** \see mdt_mod_init */
        LAST_RECV_OID           = 11UL,
        OSD_FS_ROOT_OID         = 13UL,
        ACCT_USER_OID           = 15UL,
        ACCT_GROUP_OID          = 16UL,
        LFSCK_BOOKMARK_OID      = 17UL,
        OTABLE_IT_OID           = 18UL,
        /* These two definitions are obsolete
         * OFD_GROUP0_LAST_OID     = 20UL,
         * OFD_GROUP4K_LAST_OID    = 20UL+4096,
         */
        OFD_LAST_GROUP_OID      = 4117UL,
        LLOG_CATALOGS_OID       = 4118UL,
        MGS_CONFIGS_OID         = 4119UL,
        OFD_HEALTH_CHECK_OID    = 4120UL,
        MDD_LOV_OBJ_OSEQ        = 4121UL,
        LFSCK_NAMESPACE_OID     = 4122UL,
        REMOTE_PARENT_DIR_OID   = 4123UL,
};

static inline void lu_local_obj_fid(struct lu_fid *fid, __u32 oid)
{
        fid->f_seq = FID_SEQ_LOCAL_FILE;
        fid->f_oid = oid;
        fid->f_ver = 0;
}

static inline void lu_local_name_obj_fid(struct lu_fid *fid, __u32 oid)
{
        fid->f_seq = FID_SEQ_LOCAL_NAME;
        fid->f_oid = oid;
        fid->f_ver = 0;
}

/* For new FS (>= 2.4), the root FID will be changed to
 * [FID_SEQ_ROOT:1:0], for existing FS, (upgraded to 2.4),
 * the root FID will still be IGIF */
static inline int fid_is_root(const struct lu_fid *fid)
{
        return unlikely((fid_seq(fid) == FID_SEQ_ROOT &&
                         fid_oid(fid) == 1));
}

static inline int fid_is_dot_lustre(const struct lu_fid *fid)
{
        return unlikely(fid_seq(fid) == FID_SEQ_DOT_LUSTRE &&
                        fid_oid(fid) == FID_OID_DOT_LUSTRE);
}

static inline int fid_is_obf(const struct lu_fid *fid)
{
        return unlikely(fid_seq(fid) == FID_SEQ_DOT_LUSTRE &&
                        fid_oid(fid) == FID_OID_DOT_LUSTRE_OBF);
}

static inline int fid_is_otable_it(const struct lu_fid *fid)
{
        return unlikely(fid_seq(fid) == FID_SEQ_LOCAL_FILE &&
                        fid_oid(fid) == OTABLE_IT_OID);
}

static inline int fid_is_acct(const struct lu_fid *fid)
{
        return fid_seq(fid) == FID_SEQ_LOCAL_FILE &&
               (fid_oid(fid) == ACCT_USER_OID ||
                fid_oid(fid) == ACCT_GROUP_OID);
}

static inline int fid_is_quota(const struct lu_fid *fid)
{
        return fid_seq(fid) == FID_SEQ_QUOTA ||
               fid_seq(fid) == FID_SEQ_QUOTA_GLB;
}

static inline int fid_is_namespace_visible(const struct lu_fid *fid)
{
        const __u64 seq = fid_seq(fid);

        /* Here, we cannot distinguish whether the normal FID is for OST
         * object or not. It is caller's duty to check more if needed. */
        return (!fid_is_last_id(fid) &&
                (fid_seq_is_norm(seq) || fid_seq_is_igif(seq))) ||
               fid_is_root(fid) || fid_is_dot_lustre(fid);
}

static inline int fid_seq_in_fldb(__u64 seq)
{
        return fid_seq_is_igif(seq) || fid_seq_is_norm(seq) ||
               fid_seq_is_root(seq) || fid_seq_is_dot(seq);
}

static inline void lu_last_id_fid(struct lu_fid *fid, __u64 seq)
{
        if (fid_seq_is_mdt0(seq)) {
                fid->f_seq = fid_idif_seq(0, 0);
        } else {
                LASSERTF(fid_seq_is_norm(seq) || fid_seq_is_echo(seq) ||
                         fid_seq_is_idif(seq), "%#llx\n", seq);
                fid->f_seq = seq;
        }
        fid->f_oid = 0;
        fid->f_ver = 0;
}

/* seq client type */
enum lu_cli_type {
        LUSTRE_SEQ_METADATA = 1,
        LUSTRE_SEQ_DATA
};

enum lu_mgr_type {
        LUSTRE_SEQ_SERVER,
        LUSTRE_SEQ_CONTROLLER
};

struct lu_server_seq;

/* Client sequence manager interface. */
struct lu_client_seq {
        /* Sequence-controller export. */
        struct obd_export      *lcs_exp;
        struct mutex            lcs_mutex;

        /*
         * Range of allowed for allocation sequences. When using lu_client_seq on
         * clients, this contains meta-sequence range. And for servers this
         * contains super-sequence range.
         */
        struct lu_seq_range      lcs_space;

        /* Seq related proc */
        struct dentry           *lcs_debugfs_entry;

        /* This holds last allocated fid in last obtained seq */
        struct lu_fid      lcs_fid;

        /* LUSTRE_SEQ_METADATA or LUSTRE_SEQ_DATA */
        enum lu_cli_type        lcs_type;

        /*
         * Service uuid, passed from MDT + seq name to form unique seq name to
         * use it with procfs.
         */
        char                lcs_name[LUSTRE_MDT_MAXNAMELEN];

        /*
         * Sequence width, that is how many objects may be allocated in one
         * sequence. Default value for it is LUSTRE_SEQ_MAX_WIDTH.
         */
        __u64              lcs_width;

        /* Seq-server for direct talking */
        struct lu_server_seq   *lcs_srv;

        /* wait queue for fid allocation and update indicator */
        wait_queue_head_t            lcs_waitq;
        int                  lcs_update;
};

/* server sequence manager interface */
struct lu_server_seq {
        /* Available sequences space */
        struct lu_seq_range      lss_space;

        /* keeps highwater in lsr_end for seq allocation algorithm */
        struct lu_seq_range      lss_lowater_set;
        struct lu_seq_range      lss_hiwater_set;

        /*
         * Device for server side seq manager needs (saving sequences to backing
         * store).
         */
        struct dt_device       *lss_dev;

        /* LUSTRE_SEQ_SERVER or LUSTRE_SEQ_CONTROLLER */
        enum lu_mgr_type       lss_type;

        /* Client interface to request controller */
        struct lu_client_seq   *lss_cli;

        /* Mutex for protecting allocation */
        struct mutex            lss_mutex;

        /*
         * Service uuid, passed from MDT + seq name to form unique seq name to
         * use it with procfs.
         */
        char                lss_name[LUSTRE_MDT_MAXNAMELEN];

        /*
         * Allocation chunks for super and meta sequences. Default values are
         * LUSTRE_SEQ_SUPER_WIDTH and LUSTRE_SEQ_META_WIDTH.
         */
        __u64              lss_width;

        /*
         * minimum lss_alloc_set size that should be allocated from
         * lss_space
         */
        __u64              lss_set_width;

        /* sync is needed for update operation */
        __u32              lss_need_sync;

        /**
         * Pointer to site object, required to access site fld.
         */
        struct seq_server_site  *lss_site;
};

/* Client methods */
void seq_client_flush(struct lu_client_seq *seq);

int seq_client_alloc_fid(const struct lu_env *env, struct lu_client_seq *seq,
                         struct lu_fid *fid);
int seq_client_get_seq(const struct lu_env *env, struct lu_client_seq *seq,
                       u64 *seqnr);
int seq_site_fini(const struct lu_env *env, struct seq_server_site *ss);
/* Fids common stuff */
int fid_is_local(const struct lu_env *env,
                 struct lu_site *site, const struct lu_fid *fid);

enum lu_cli_type;
int client_fid_init(struct obd_device *obd, struct obd_export *exp,
                    enum lu_cli_type type);
int client_fid_fini(struct obd_device *obd);

/* fid locking */

struct ldlm_namespace;

/*
 * Build (DLM) resource name from FID.
 *
 * NOTE: until Lustre 1.8.7/2.1.1 the fid_ver() was packed into name[2],
 * but was moved into name[1] along with the OID to avoid consuming the
 * renaming name[2,3] fields that need to be used for the quota identifier.
 */
static inline struct ldlm_res_id *
fid_build_reg_res_name(const struct lu_fid *fid, struct ldlm_res_id *res)
{
        memset(res, 0, sizeof(*res));
        res->name[LUSTRE_RES_ID_SEQ_OFF] = fid_seq(fid);
        res->name[LUSTRE_RES_ID_VER_OID_OFF] = fid_ver_oid(fid);

        return res;
}

/*
 * Return true if resource is for object identified by FID.
 */
static inline int fid_res_name_eq(const struct lu_fid *fid,
                                  const struct ldlm_res_id *res)
{
        return res->name[LUSTRE_RES_ID_SEQ_OFF] == fid_seq(fid) &&
               res->name[LUSTRE_RES_ID_VER_OID_OFF] == fid_ver_oid(fid);
}

/*
 * Extract FID from LDLM resource. Reverse of fid_build_reg_res_name().
 */
static inline struct lu_fid *
fid_extract_from_res_name(struct lu_fid *fid, const struct ldlm_res_id *res)
{
        fid->f_seq = res->name[LUSTRE_RES_ID_SEQ_OFF];
        fid->f_oid = (__u32)(res->name[LUSTRE_RES_ID_VER_OID_OFF]);
        fid->f_ver = (__u32)(res->name[LUSTRE_RES_ID_VER_OID_OFF] >> 32);
        LASSERT(fid_res_name_eq(fid, res));

        return fid;
}

/*
 * Build (DLM) resource identifier from global quota FID and quota ID.
 */
static inline struct ldlm_res_id *
fid_build_quota_res_name(const struct lu_fid *glb_fid, union lquota_id *qid,
                      struct ldlm_res_id *res)
{
        fid_build_reg_res_name(glb_fid, res);
        res->name[LUSTRE_RES_ID_QUOTA_SEQ_OFF] = fid_seq(&qid->qid_fid);
        res->name[LUSTRE_RES_ID_QUOTA_VER_OID_OFF] = fid_ver_oid(&qid->qid_fid);

        return res;
}

/*
 * Extract global FID and quota ID from resource name
 */
static inline void fid_extract_from_quota_res(struct lu_fid *glb_fid,
                                              union lquota_id *qid,
                                              const struct ldlm_res_id *res)
{
        fid_extract_from_res_name(glb_fid, res);
        qid->qid_fid.f_seq = res->name[LUSTRE_RES_ID_QUOTA_SEQ_OFF];
        qid->qid_fid.f_oid = (__u32)res->name[LUSTRE_RES_ID_QUOTA_VER_OID_OFF];
        qid->qid_fid.f_ver =
                (__u32)(res->name[LUSTRE_RES_ID_QUOTA_VER_OID_OFF] >> 32);
}

static inline struct ldlm_res_id *
fid_build_pdo_res_name(const struct lu_fid *fid, unsigned int hash,
                       struct ldlm_res_id *res)
{
        fid_build_reg_res_name(fid, res);
        res->name[LUSTRE_RES_ID_HSH_OFF] = hash;

        return res;
}

/**
 * Build DLM resource name from object id & seq, which will be removed
 * finally, when we replace ost_id with FID in data stack.
 *
 * Currently, resid from the old client, whose res[0] = object_id,
 * res[1] = object_seq, is just opposite with Metatdata
 * resid, where, res[0] = fid->f_seq, res[1] = fid->f_oid.
 * To unify the resid identification, we will reverse the data
 * resid to keep it same with Metadata resid, i.e.
 *
 * For resid from the old client,
 *    res[0] = objid,  res[1] = 0, still keep the original order,
 *    for compatibility.
 *
 * For new resid
 *    res will be built from normal FID directly, i.e. res[0] = f_seq,
 *    res[1] = f_oid + f_ver.
 */
static inline void ostid_build_res_name(struct ost_id *oi,
                                        struct ldlm_res_id *name)
{
        memset(name, 0, sizeof(*name));
        if (fid_seq_is_mdt0(ostid_seq(oi))) {
                name->name[LUSTRE_RES_ID_SEQ_OFF] = ostid_id(oi);
                name->name[LUSTRE_RES_ID_VER_OID_OFF] = ostid_seq(oi);
        } else {
                fid_build_reg_res_name(&oi->oi_fid, name);
        }
}

static inline void ostid_res_name_to_id(struct ost_id *oi,
                                        struct ldlm_res_id *name)
{
        if (fid_seq_is_mdt0(name->name[LUSTRE_RES_ID_SEQ_OFF])) {
                /* old resid */
                ostid_set_seq(oi, name->name[LUSTRE_RES_ID_VER_OID_OFF]);
                ostid_set_id(oi, name->name[LUSTRE_RES_ID_SEQ_OFF]);
        } else {
                /* new resid */
                fid_extract_from_res_name(&oi->oi_fid, name);
        }
}

/**
 * Return true if the resource is for the object identified by this id & group.
 */
static inline int ostid_res_name_eq(struct ost_id *oi,
                                    struct ldlm_res_id *name)
{
        /* Note: it is just a trick here to save some effort, probably the
         * correct way would be turn them into the FID and compare */
        if (fid_seq_is_mdt0(ostid_seq(oi))) {
                return name->name[LUSTRE_RES_ID_SEQ_OFF] == ostid_id(oi) &&
                       name->name[LUSTRE_RES_ID_VER_OID_OFF] == ostid_seq(oi);
        } else {
                return name->name[LUSTRE_RES_ID_SEQ_OFF] == ostid_seq(oi) &&
                       name->name[LUSTRE_RES_ID_VER_OID_OFF] == ostid_id(oi);
        }
}

/* The same as osc_build_res_name() */
static inline void ost_fid_build_resid(const struct lu_fid *fid,
                                       struct ldlm_res_id *resname)
{
        if (fid_is_mdt0(fid) || fid_is_idif(fid)) {
                struct ost_id oi;
                oi.oi.oi_id = 0; /* gcc 4.7.2 complains otherwise */
                if (fid_to_ostid(fid, &oi) != 0)
                        return;
                ostid_build_res_name(&oi, resname);
        } else {
                fid_build_reg_res_name(fid, resname);
        }
}

static inline void ost_fid_from_resid(struct lu_fid *fid,
                                      const struct ldlm_res_id *name)
{
        if (fid_seq_is_mdt0(name->name[LUSTRE_RES_ID_VER_OID_OFF])) {
                /* old resid */
                struct ost_id oi;
                ostid_set_seq(&oi, name->name[LUSTRE_RES_ID_VER_OID_OFF]);
                ostid_set_id(&oi, name->name[LUSTRE_RES_ID_SEQ_OFF]);
                ostid_to_fid(fid, &oi, 0);
        } else {
                /* new resid */
                fid_extract_from_res_name(fid, name);
        }
}

/**
 * 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_flatten(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 ? ino : fid_oid(fid);
}

static inline __u32 fid_hash(const struct lu_fid *f, int bits)
{
        /* all objects with same id and different versions will belong to same
         * collisions list. */
        return hash_long(fid_flatten(f), bits);
}

/**
 * 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 ? ino : fid_oid(fid);
}

static inline int lu_fid_diff(struct lu_fid *fid1, struct lu_fid *fid2)
{
        LASSERTF(fid_seq(fid1) == fid_seq(fid2), "fid1:"DFID", fid2:"DFID"\n",
                 PFID(fid1), PFID(fid2));

        if (fid_is_idif(fid1) && fid_is_idif(fid2))
                return fid_idif_id(fid1->f_seq, fid1->f_oid, fid1->f_ver) -
                       fid_idif_id(fid2->f_seq, fid2->f_oid, fid2->f_ver);

        return fid_oid(fid1) - fid_oid(fid2);
}

#define LUSTRE_SEQ_SRV_NAME "seq_srv"
#define LUSTRE_SEQ_CTL_NAME "seq_ctl"

/* Range common stuff */
static inline void range_cpu_to_le(struct lu_seq_range *dst, const struct lu_seq_range *src)
{
        dst->lsr_start = cpu_to_le64(src->lsr_start);
        dst->lsr_end = cpu_to_le64(src->lsr_end);
        dst->lsr_index = cpu_to_le32(src->lsr_index);
        dst->lsr_flags = cpu_to_le32(src->lsr_flags);
}

static inline void range_le_to_cpu(struct lu_seq_range *dst, const struct lu_seq_range *src)
{
        dst->lsr_start = le64_to_cpu(src->lsr_start);
        dst->lsr_end = le64_to_cpu(src->lsr_end);
        dst->lsr_index = le32_to_cpu(src->lsr_index);
        dst->lsr_flags = le32_to_cpu(src->lsr_flags);
}

static inline void range_cpu_to_be(struct lu_seq_range *dst, const struct lu_seq_range *src)
{
        dst->lsr_start = cpu_to_be64(src->lsr_start);
        dst->lsr_end = cpu_to_be64(src->lsr_end);
        dst->lsr_index = cpu_to_be32(src->lsr_index);
        dst->lsr_flags = cpu_to_be32(src->lsr_flags);
}

static inline void range_be_to_cpu(struct lu_seq_range *dst, const struct lu_seq_range *src)
{
        dst->lsr_start = be64_to_cpu(src->lsr_start);
        dst->lsr_end = be64_to_cpu(src->lsr_end);
        dst->lsr_index = be32_to_cpu(src->lsr_index);
        dst->lsr_flags = be32_to_cpu(src->lsr_flags);
}

/** @} fid */

#endif /* __LUSTRE_FID_H */