/*
 * 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) 2012, 2015, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 *
 * lustre/include/lustre_log.h
 *
 * Generic infrastructure for managing a collection of logs.
 * These logs are used for:
 *
 * - orphan recovery: OST adds record on create
 * - mtime/size consistency: the OST adds a record on first write
 * - open/unlinked objects: OST adds a record on destroy
 *
 * - mds unlink log: the MDS adds an entry upon delete
 *
 * - raid1 replication log between OST's
 * - MDS replication logs
 */

#ifndef _LUSTRE_LOG_H
#define _LUSTRE_LOG_H

/** \defgroup log log
 *
 * @{
 */

#include "obd_class.h"
#include "lustre/lustre_idl.h"

#define LOG_NAME_LIMIT(logname, name)              \
        snprintf(logname, sizeof(logname), "LOGS/%s", name)
#define LLOG_EEMPTY 4711

enum llog_open_param {
        LLOG_OPEN_EXISTS        = 0x0000,
        LLOG_OPEN_NEW           = 0x0001,
};

struct plain_handle_data {
        struct list_head          phd_entry;
        struct llog_handle *phd_cat_handle;
        struct llog_cookie  phd_cookie; /* cookie of this log in its cat */
};

struct cat_handle_data {
        struct list_head              chd_head;
        struct llog_handle     *chd_current_log; /* currently open log */
        struct llog_handle      *chd_next_log; /* llog to be used next */
};

struct llog_handle;

/* llog.c  -  general API */
int llog_init_handle(const struct lu_env *env, struct llog_handle *handle,
                     int flags, struct obd_uuid *uuid);
int llog_process(const struct lu_env *env, struct llog_handle *loghandle,
                 llog_cb_t cb, void *data, void *catdata);
int llog_process_or_fork(const struct lu_env *env,
                         struct llog_handle *loghandle,
                         llog_cb_t cb, void *data, void *catdata, bool fork);
int llog_open(const struct lu_env *env, struct llog_ctxt *ctxt,
              struct llog_handle **lgh, struct llog_logid *logid,
              char *name, enum llog_open_param open_param);
int llog_close(const struct lu_env *env, struct llog_handle *cathandle);

/* llog_process flags */
#define LLOG_FLAG_NODEAMON 0x0001

/* llog_cat.c - catalog api */
struct llog_process_data {
        /**
         * Any useful data needed while processing catalog. This is
         * passed later to process callback.
         */
        void            *lpd_data;
        /**
         * Catalog process callback function, called for each record
         * in catalog.
         */
        llog_cb_t           lpd_cb;
        /**
         * Start processing the catalog from startcat/startidx
         */
        int               lpd_startcat;
        int               lpd_startidx;
};

struct llog_process_cat_data {
        /**
         * Temporary stored first_idx while scanning log.
         */
        int               lpcd_first_idx;
        /**
         * Temporary stored last_idx while scanning log.
         */
        int               lpcd_last_idx;
};

struct thandle;

int llog_cat_close(const struct lu_env *env, struct llog_handle *cathandle);
int llog_cat_process(const struct lu_env *env, struct llog_handle *cat_llh,
                     llog_cb_t cb, void *data, int startcat, int startidx);

/* llog_obd.c */
int llog_setup(const struct lu_env *env, struct obd_device *obd,
               struct obd_llog_group *olg, int index,
               struct obd_device *disk_obd, struct llog_operations *op);
int __llog_ctxt_put(const struct lu_env *env, struct llog_ctxt *ctxt);
int llog_cleanup(const struct lu_env *env, struct llog_ctxt *);

/* llog_net.c */
int llog_initiator_connect(struct llog_ctxt *ctxt);

struct llog_operations {
        int (*lop_next_block)(const struct lu_env *env, struct llog_handle *h,
                              int *curr_idx, int next_idx, __u64 *offset,
                              void *buf, int len);
        int (*lop_prev_block)(const struct lu_env *env, struct llog_handle *h,
                              int prev_idx, void *buf, int len);
        int (*lop_read_header)(const struct lu_env *env,
                               struct llog_handle *handle);
        int (*lop_setup)(const struct lu_env *env, struct obd_device *obd,
                         struct obd_llog_group *olg, int ctxt_idx,
                         struct obd_device *disk_obd);
        int (*lop_sync)(struct llog_ctxt *ctxt, struct obd_export *exp,
                        int flags);
        int (*lop_cleanup)(const struct lu_env *env, struct llog_ctxt *ctxt);
        int (*lop_cancel)(const struct lu_env *env, struct llog_ctxt *ctxt,
                          struct llog_cookie *cookies, int flags);
        int (*lop_connect)(struct llog_ctxt *ctxt, struct llog_logid *logid,
                           struct llog_gen *gen, struct obd_uuid *uuid);
        /**
         * Any llog file must be opened first using llog_open().  Llog can be
         * opened by name, logid or without both, in last case the new logid
         * will be generated.
         */
        int (*lop_open)(const struct lu_env *env, struct llog_handle *lgh,
                        struct llog_logid *logid, char *name,
                        enum llog_open_param);
        /**
         * Opened llog may not exist and this must be checked where needed using
         * the llog_exist() call.
         */
        int (*lop_exist)(struct llog_handle *lgh);
        /**
         * Close llog file and calls llog_free_handle() implicitly.
         * Any opened llog must be closed by llog_close() call.
         */
        int (*lop_close)(const struct lu_env *env, struct llog_handle *handle);
        /**
         * Create new llog file. The llog must be opened.
         * Must be used only for local llog operations.
         */
        int (*lop_declare_create)(const struct lu_env *env,
                                  struct llog_handle *handle,
                                  struct thandle *th);
        /**
         * write new record in llog. It appends records usually but can edit
         * existing records too.
         */
        int (*lop_declare_write_rec)(const struct lu_env *env,
                                     struct llog_handle *lgh,
                                     struct llog_rec_hdr *rec,
                                     int idx, struct thandle *th);
        int (*lop_write_rec)(const struct lu_env *env,
                             struct llog_handle *loghandle,
                             struct llog_rec_hdr *rec,
                             struct llog_cookie *cookie, int cookiecount,
                             void *buf, int idx, struct thandle *th);
        /**
         * Add new record in llog catalog. Does the same as llog_write_rec()
         * but using llog catalog.
         */
        int (*lop_declare_add)(const struct lu_env *env,
                               struct llog_handle *lgh,
                               struct llog_rec_hdr *rec, struct thandle *th);
        int (*lop_add)(const struct lu_env *env, struct llog_handle *lgh,
                       struct llog_rec_hdr *rec, struct llog_cookie *cookie,
                       void *buf, struct thandle *th);
};

/* In-memory descriptor for a log object or log catalog */
struct llog_handle {
        struct rw_semaphore      lgh_lock;
        spinlock_t               lgh_hdr_lock; /* protect lgh_hdr data */
        struct llog_logid        lgh_id; /* id of this log */
        struct llog_log_hdr     *lgh_hdr;
        size_t                   lgh_hdr_size;
        int                      lgh_last_idx;
        int                      lgh_cur_idx; /* used during llog_process */
        __u64                    lgh_cur_offset; /* used during llog_process */
        struct llog_ctxt        *lgh_ctxt;
        union {
                struct plain_handle_data         phd;
                struct cat_handle_data           chd;
        } u;
        char                    *lgh_name;
        void                    *private_data;
        struct llog_operations  *lgh_logops;
        atomic_t                 lgh_refcount;
};

#define LLOG_CTXT_FLAG_UNINITIALIZED     0x00000001
#define LLOG_CTXT_FLAG_STOP              0x00000002

struct llog_ctxt {
        int                   loc_idx; /* my index the obd array of ctxt's */
        struct obd_device       *loc_obd; /* points back to the containing obd*/
        struct obd_llog_group   *loc_olg; /* group containing that ctxt */
        struct obd_export       *loc_exp; /* parent "disk" export (e.g. MDS) */
        struct obd_import       *loc_imp; /* to use in RPC's: can be backward
                                           * pointing import
                                           */
        struct llog_operations  *loc_logops;
        struct llog_handle      *loc_handle;
        struct mutex             loc_mutex; /* protect loc_imp */
        atomic_t             loc_refcount;
        long                 loc_flags; /* flags, see above defines */
        /*
         * llog chunk size, and llog record size can not be bigger than
         * loc_chunk_size
         */
        __u32                   loc_chunk_size;
};

#define LLOG_PROC_BREAK 0x0001
#define LLOG_DEL_RECORD 0x0002

static inline int llog_handle2ops(struct llog_handle *loghandle,
                                  struct llog_operations **lop)
{
        if (!loghandle || !loghandle->lgh_logops)
                return -EINVAL;

        *lop = loghandle->lgh_logops;
        return 0;
}

static inline struct llog_ctxt *llog_ctxt_get(struct llog_ctxt *ctxt)
{
        atomic_inc(&ctxt->loc_refcount);
        CDEBUG(D_INFO, "GETting ctxt %p : new refcount %d\n", ctxt,
               atomic_read(&ctxt->loc_refcount));
        return ctxt;
}

static inline void llog_ctxt_put(struct llog_ctxt *ctxt)
{
        if (!ctxt)
                return;
        LASSERT_ATOMIC_GT_LT(&ctxt->loc_refcount, 0, LI_POISON);
        CDEBUG(D_INFO, "PUTting ctxt %p : new refcount %d\n", ctxt,
               atomic_read(&ctxt->loc_refcount) - 1);
        __llog_ctxt_put(NULL, ctxt);
}

static inline void llog_group_init(struct obd_llog_group *olg)
{
        init_waitqueue_head(&olg->olg_waitq);
        spin_lock_init(&olg->olg_lock);
        mutex_init(&olg->olg_cat_processing);
}

static inline int llog_group_set_ctxt(struct obd_llog_group *olg,
                                      struct llog_ctxt *ctxt, int index)
{
        LASSERT(index >= 0 && index < LLOG_MAX_CTXTS);

        spin_lock(&olg->olg_lock);
        if (olg->olg_ctxts[index]) {
                spin_unlock(&olg->olg_lock);
                return -EEXIST;
        }
        olg->olg_ctxts[index] = ctxt;
        spin_unlock(&olg->olg_lock);
        return 0;
}

static inline struct llog_ctxt *llog_group_get_ctxt(struct obd_llog_group *olg,
                                                    int index)
{
        struct llog_ctxt *ctxt;

        LASSERT(index >= 0 && index < LLOG_MAX_CTXTS);

        spin_lock(&olg->olg_lock);
        if (!olg->olg_ctxts[index])
                ctxt = NULL;
        else
                ctxt = llog_ctxt_get(olg->olg_ctxts[index]);
        spin_unlock(&olg->olg_lock);
        return ctxt;
}

static inline void llog_group_clear_ctxt(struct obd_llog_group *olg, int index)
{
        LASSERT(index >= 0 && index < LLOG_MAX_CTXTS);
        spin_lock(&olg->olg_lock);
        olg->olg_ctxts[index] = NULL;
        spin_unlock(&olg->olg_lock);
}

static inline struct llog_ctxt *llog_get_context(struct obd_device *obd,
                                                 int index)
{
        return llog_group_get_ctxt(&obd->obd_olg, index);
}

static inline int llog_group_ctxt_null(struct obd_llog_group *olg, int index)
{
        return (!olg->olg_ctxts[index]);
}

static inline int llog_ctxt_null(struct obd_device *obd, int index)
{
        return llog_group_ctxt_null(&obd->obd_olg, index);
}

static inline int llog_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 llog_operations *lop;
        int rc;

        rc = llog_handle2ops(loghandle, &lop);
        if (rc)
                return rc;
        if (!lop->lop_next_block)
                return -EOPNOTSUPP;

        rc = lop->lop_next_block(env, loghandle, cur_idx, next_idx,
                                 cur_offset, buf, len);
        return rc;
}

/* llog.c */
int llog_declare_write_rec(const struct lu_env *env,
                           struct llog_handle *handle,
                           struct llog_rec_hdr *rec, int idx,
                           struct thandle *th);
int llog_write_rec(const struct lu_env *env, struct llog_handle *handle,
                   struct llog_rec_hdr *rec, struct llog_cookie *logcookies,
                   int numcookies, void *buf, int idx, struct thandle *th);
int lustre_process_log(struct super_block *sb, char *logname,
                       struct config_llog_instance *cfg);
int lustre_end_log(struct super_block *sb, char *logname,
                   struct config_llog_instance *cfg);
/** @} log */

#endif