/*
 * Copyright (c) 2007-2008 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@backplane.com>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name of The DragonFly Project nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific, prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "hammer.h"

static uint32_t ocp_allocbit(hammer_objid_cache_t ocp, uint32_t n);


/*
 * Start a standard transaction.
 *
 * May be called without fs_token
 */
void
hammer_start_transaction(hammer_transaction_t trans, hammer_mount_t hmp)
{
        struct timespec ts;
        int error;

        trans->type = HAMMER_TRANS_STD;
        trans->hmp = hmp;
        trans->rootvol = hammer_get_root_volume(hmp, &error);
        KKASSERT(error == 0);
        trans->tid = 0;
        trans->sync_lock_refs = 0;
        trans->flags = 0;

        vfs_timestamp(&ts);
        trans->time = (unsigned long)ts.tv_sec * 1000000ULL +
                      ts.tv_nsec / 1000;
        trans->time32 = (uint32_t)ts.tv_sec;
}

/*
 * Start a simple read-only transaction.  This will not stall.
 *
 * May be called without fs_token
 */
void
hammer_simple_transaction(hammer_transaction_t trans, hammer_mount_t hmp)
{
        struct timespec ts;
        int error;

        trans->type = HAMMER_TRANS_RO;
        trans->hmp = hmp;
        trans->rootvol = hammer_get_root_volume(hmp, &error);
        KKASSERT(error == 0);
        trans->tid = 0;
        trans->sync_lock_refs = 0;
        trans->flags = 0;

        vfs_timestamp(&ts);
        trans->time = (unsigned long)ts.tv_sec * 1000000ULL +
                      ts.tv_nsec / 1000;
        trans->time32 = (uint32_t)ts.tv_sec;
}

/*
 * Start a transaction using a particular TID.  Used by the sync code.
 * This does not stall.
 *
 * This routine may only be called from the flusher thread.  We predispose
 * sync_lock_refs, implying serialization against the synchronization stage
 * (which the flusher is responsible for).
 */
void
hammer_start_transaction_fls(hammer_transaction_t trans, hammer_mount_t hmp)
{
        struct timespec ts;
        int error;

        bzero(trans, sizeof(*trans));

        trans->type = HAMMER_TRANS_FLS;
        trans->hmp = hmp;
        trans->rootvol = hammer_get_root_volume(hmp, &error);
        KKASSERT(error == 0);
        trans->tid = hammer_alloc_tid(hmp, 1);
        trans->sync_lock_refs = 1;
        trans->flags = 0;

        vfs_timestamp(&ts);
        trans->time = (unsigned long)ts.tv_sec * 1000000ULL +
                      ts.tv_nsec / 1000;
        trans->time32 = (uint32_t)ts.tv_sec;
}

/*
 * May be called without fs_token
 */
void
hammer_done_transaction(hammer_transaction_t trans)
{
        int expected_lock_refs __debugvar;

        hammer_rel_volume(trans->rootvol, 0);
        trans->rootvol = NULL;
        expected_lock_refs = (trans->type == HAMMER_TRANS_FLS) ? 1 : 0;
        KKASSERT(trans->sync_lock_refs == expected_lock_refs);
        trans->sync_lock_refs = 0;
        if (trans->type != HAMMER_TRANS_FLS) {
                if (trans->flags & HAMMER_TRANSF_NEWINODE) {
                        lwkt_gettoken(&trans->hmp->fs_token);
                        hammer_inode_waitreclaims(trans);
                        lwkt_reltoken(&trans->hmp->fs_token);
                }
        }
}

/*
 * Allocate (count) TIDs.  If running in multi-master mode the returned
 * base will be aligned to a 16-count plus the master id (0-15).
 * Multi-master mode allows non-conflicting to run and new objects to be
 * created on multiple masters in parallel.  The transaction id identifies
 * the original master.  The object_id is also subject to this rule in
 * order to allow objects to be created on multiple masters in parallel.
 *
 * Directories may pre-allocate a large number of object ids (100,000).
 *
 * NOTE: There is no longer a requirement that successive transaction
 *       ids be 2 apart for separator generation.
 *
 * NOTE: When called by pseudo-backends such as ioctls the allocated
 *       TID will be larger then the current flush TID, if a flush is running,
 *       so any mirroring will pick the records up on a later flush.
 *
 * NOTE: HAMMER1 does not support multi-master clustering as of 2015.
 */
hammer_tid_t
hammer_alloc_tid(hammer_mount_t hmp, int count)
{
        hammer_tid_t tid;

        if (hmp->master_id < 0) {
                tid = hmp->next_tid + 1;
                hmp->next_tid = tid + count;
        } else {
                tid = (hmp->next_tid + HAMMER_MAX_MASTERS) &
                      ~(hammer_tid_t)(HAMMER_MAX_MASTERS - 1);
                hmp->next_tid = tid + count * HAMMER_MAX_MASTERS;
                tid |= hmp->master_id;
        }
        if (tid >= 0xFFFFFFFFFF000000ULL)
                hpanic("Ran out of TIDs!");
        if (hammer_debug_tid)
                hdkprintf("%016jx\n", (intmax_t)tid);
        return(tid);
}

/*
 * Allocate an object id.
 *
 * We use the upper OBJID_CACHE_BITS bits of the namekey to try to match
 * the low bits of the objid we allocate.
 */
hammer_tid_t
hammer_alloc_objid(hammer_mount_t hmp, hammer_inode_t dip, int64_t namekey)
{
        hammer_objid_cache_t ocp;
        hammer_tid_t tid;
        uint32_t n;

        while ((ocp = dip->objid_cache) == NULL) {
                if (hmp->objid_cache_count < OBJID_CACHE_SIZE) {
                        ocp = kmalloc(sizeof(*ocp), hmp->m_misc,
                                      M_WAITOK|M_ZERO);
                        ocp->base_tid = hammer_alloc_tid(hmp,
                                                        OBJID_CACHE_BULK * 2);
                        ocp->base_tid += OBJID_CACHE_BULK_MASK64;
                        ocp->base_tid &= ~OBJID_CACHE_BULK_MASK64;
                        /* may have blocked, recheck */
                        if (dip->objid_cache == NULL) {
                                TAILQ_INSERT_TAIL(&hmp->objid_cache_list,
                                                  ocp, entry);
                                ++hmp->objid_cache_count;
                                dip->objid_cache = ocp;
                                ocp->dip = dip;
                        } else {
                                kfree(ocp, hmp->m_misc);
                        }
                } else {
                        /*
                         * Steal one from another directory?
                         *
                         * Throw away ocp's that are more then half full, they
                         * aren't worth stealing.
                         */
                        ocp = TAILQ_FIRST(&hmp->objid_cache_list);
                        if (ocp->dip)
                                ocp->dip->objid_cache = NULL;
                        if (ocp->count >= OBJID_CACHE_BULK / 2) {
                                TAILQ_REMOVE(&hmp->objid_cache_list,
                                             ocp, entry);
                                --hmp->objid_cache_count;
                                kfree(ocp, hmp->m_misc);
                        } else {
                                dip->objid_cache = ocp;
                                ocp->dip = dip;
                        }
                }
        }
        TAILQ_REMOVE(&hmp->objid_cache_list, ocp, entry);

        /*
         * Allocate inode numbers uniformly.
         */

        n = (namekey >> (63 - OBJID_CACHE_BULK_BITS)) & OBJID_CACHE_BULK_MASK;
        n = ocp_allocbit(ocp, n);
        tid = ocp->base_tid + n;

#if 0
        /*
         * The TID is incremented by 1 or by 16 depending what mode the
         * mount is operating in.
         */
        ocp->next_tid += (hmp->master_id < 0) ? 1 : HAMMER_MAX_MASTERS;
#endif
        if (ocp->count >= OBJID_CACHE_BULK * 3 / 4) {
                dip->objid_cache = NULL;
                --hmp->objid_cache_count;
                ocp->dip = NULL;
                kfree(ocp, hmp->m_misc);
        } else {
                TAILQ_INSERT_TAIL(&hmp->objid_cache_list, ocp, entry);
        }
        return(tid);
}

/*
 * Allocate a bit starting with bit n.  Wrap if necessary.
 *
 * This routine is only ever called if a bit is available somewhere
 * in the bitmap.
 */
static uint32_t
ocp_allocbit(hammer_objid_cache_t ocp, uint32_t n)
{
        uint32_t n0;

        n0 = (n >> 5) & 31;
        n &= 31;

        while (ocp->bm1[n0] & (1 << n)) {
                if (ocp->bm0 & (1 << n0)) {
                        n0 = (n0 + 1) & 31;
                        n = 0;
                } else if (++n == 32) {
                        n0 = (n0 + 1) & 31;
                        n = 0;
                }
        }
        ++ocp->count;
        ocp->bm1[n0] |= 1 << n;
        if (ocp->bm1[n0] == 0xFFFFFFFFU)
                ocp->bm0 |= 1 << n0;
        return((n0 << 5) + n);
}

void
hammer_clear_objid(hammer_inode_t dip)
{
        hammer_objid_cache_t ocp;

        if ((ocp = dip->objid_cache) != NULL) {
                dip->objid_cache = NULL;
                ocp->dip = NULL;
                TAILQ_REMOVE(&dip->hmp->objid_cache_list, ocp, entry);
                TAILQ_INSERT_HEAD(&dip->hmp->objid_cache_list, ocp, entry);
        }
}

void
hammer_destroy_objid_cache(hammer_mount_t hmp)
{
        hammer_objid_cache_t ocp;

        while ((ocp = TAILQ_FIRST(&hmp->objid_cache_list)) != NULL) {
                TAILQ_REMOVE(&hmp->objid_cache_list, ocp, entry);
                if (ocp->dip)
                        ocp->dip->objid_cache = NULL;
                kfree(ocp, hmp->m_misc);
                --hmp->objid_cache_count;
        }
        KKASSERT(hmp->objid_cache_count == 0);
}