/*
 * Copyright (C) 2016 Oracle.  All Rights Reserved.
 *
 * Author: Darrick J. Wong <darrick.wong@oracle.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it would 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA.
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_defer.h"
#include "xfs_trans.h"
#include "xfs_trans_priv.h"
#include "xfs_refcount_item.h"
#include "xfs_alloc.h"
#include "xfs_refcount.h"

/*
 * This routine is called to allocate a "refcount update done"
 * log item.
 */
struct xfs_cud_log_item *
xfs_trans_get_cud(
        struct xfs_trans                *tp,
        struct xfs_cui_log_item         *cuip)
{
        struct xfs_cud_log_item         *cudp;

        cudp = xfs_cud_init(tp->t_mountp, cuip);
        xfs_trans_add_item(tp, &cudp->cud_item);
        return cudp;
}

/*
 * Finish an refcount update and log it to the CUD. Note that the
 * transaction is marked dirty regardless of whether the refcount
 * update succeeds or fails to support the CUI/CUD lifecycle rules.
 */
int
xfs_trans_log_finish_refcount_update(
        struct xfs_trans                *tp,
        struct xfs_cud_log_item         *cudp,
        struct xfs_defer_ops            *dop,
        enum xfs_refcount_intent_type   type,
        xfs_fsblock_t                   startblock,
        xfs_extlen_t                    blockcount,
        xfs_fsblock_t                   *new_fsb,
        xfs_extlen_t                    *new_len,
        struct xfs_btree_cur            **pcur)
{
        int                             error;

        error = xfs_refcount_finish_one(tp, dop, type, startblock,
                        blockcount, new_fsb, new_len, pcur);

        /*
         * Mark the transaction dirty, even on error. This ensures the
         * transaction is aborted, which:
         *
         * 1.) releases the CUI and frees the CUD
         * 2.) shuts down the filesystem
         */
        tp->t_flags |= XFS_TRANS_DIRTY;
        cudp->cud_item.li_desc->lid_flags |= XFS_LID_DIRTY;

        return error;
}

/* Sort refcount intents by AG. */
static int
xfs_refcount_update_diff_items(
        void                            *priv,
        struct list_head                *a,
        struct list_head                *b)
{
        struct xfs_mount                *mp = priv;
        struct xfs_refcount_intent      *ra;
        struct xfs_refcount_intent      *rb;

        ra = container_of(a, struct xfs_refcount_intent, ri_list);
        rb = container_of(b, struct xfs_refcount_intent, ri_list);
        return  XFS_FSB_TO_AGNO(mp, ra->ri_startblock) -
                XFS_FSB_TO_AGNO(mp, rb->ri_startblock);
}

/* Get an CUI. */
STATIC void *
xfs_refcount_update_create_intent(
        struct xfs_trans                *tp,
        unsigned int                    count)
{
        struct xfs_cui_log_item         *cuip;

        ASSERT(tp != NULL);
        ASSERT(count > 0);

        cuip = xfs_cui_init(tp->t_mountp, count);
        ASSERT(cuip != NULL);

        /*
         * Get a log_item_desc to point at the new item.
         */
        xfs_trans_add_item(tp, &cuip->cui_item);
        return cuip;
}

/* Set the phys extent flags for this reverse mapping. */
static void
xfs_trans_set_refcount_flags(
        struct xfs_phys_extent          *refc,
        enum xfs_refcount_intent_type   type)
{
        refc->pe_flags = 0;
        switch (type) {
        case XFS_REFCOUNT_INCREASE:
        case XFS_REFCOUNT_DECREASE:
        case XFS_REFCOUNT_ALLOC_COW:
        case XFS_REFCOUNT_FREE_COW:
                refc->pe_flags |= type;
                break;
        default:
                ASSERT(0);
        }
}

/* Log refcount updates in the intent item. */
STATIC void
xfs_refcount_update_log_item(
        struct xfs_trans                *tp,
        void                            *intent,
        struct list_head                *item)
{
        struct xfs_cui_log_item         *cuip = intent;
        struct xfs_refcount_intent      *refc;
        uint                            next_extent;
        struct xfs_phys_extent          *ext;

        refc = container_of(item, struct xfs_refcount_intent, ri_list);

        tp->t_flags |= XFS_TRANS_DIRTY;
        cuip->cui_item.li_desc->lid_flags |= XFS_LID_DIRTY;

        /*
         * atomic_inc_return gives us the value after the increment;
         * we want to use it as an array index so we need to subtract 1 from
         * it.
         */
        next_extent = atomic_inc_return(&cuip->cui_next_extent) - 1;
        ASSERT(next_extent < cuip->cui_format.cui_nextents);
        ext = &cuip->cui_format.cui_extents[next_extent];
        ext->pe_startblock = refc->ri_startblock;
        ext->pe_len = refc->ri_blockcount;
        xfs_trans_set_refcount_flags(ext, refc->ri_type);
}

/* Get an CUD so we can process all the deferred refcount updates. */
STATIC void *
xfs_refcount_update_create_done(
        struct xfs_trans                *tp,
        void                            *intent,
        unsigned int                    count)
{
        return xfs_trans_get_cud(tp, intent);
}

/* Process a deferred refcount update. */
STATIC int
xfs_refcount_update_finish_item(
        struct xfs_trans                *tp,
        struct xfs_defer_ops            *dop,
        struct list_head                *item,
        void                            *done_item,
        void                            **state)
{
        struct xfs_refcount_intent      *refc;
        xfs_fsblock_t                   new_fsb;
        xfs_extlen_t                    new_aglen;
        int                             error;

        refc = container_of(item, struct xfs_refcount_intent, ri_list);
        error = xfs_trans_log_finish_refcount_update(tp, done_item, dop,
                        refc->ri_type,
                        refc->ri_startblock,
                        refc->ri_blockcount,
                        &new_fsb, &new_aglen,
                        (struct xfs_btree_cur **)state);
        /* Did we run out of reservation?  Requeue what we didn't finish. */
        if (!error && new_aglen > 0) {
                ASSERT(refc->ri_type == XFS_REFCOUNT_INCREASE ||
                       refc->ri_type == XFS_REFCOUNT_DECREASE);
                refc->ri_startblock = new_fsb;
                refc->ri_blockcount = new_aglen;
                return -EAGAIN;
        }
        kmem_free(refc);
        return error;
}

/* Clean up after processing deferred refcounts. */
STATIC void
xfs_refcount_update_finish_cleanup(
        struct xfs_trans        *tp,
        void                    *state,
        int                     error)
{
        struct xfs_btree_cur    *rcur = state;

        xfs_refcount_finish_one_cleanup(tp, rcur, error);
}

/* Abort all pending CUIs. */
STATIC void
xfs_refcount_update_abort_intent(
        void                            *intent)
{
        xfs_cui_release(intent);
}

/* Cancel a deferred refcount update. */
STATIC void
xfs_refcount_update_cancel_item(
        struct list_head                *item)
{
        struct xfs_refcount_intent      *refc;

        refc = container_of(item, struct xfs_refcount_intent, ri_list);
        kmem_free(refc);
}

static const struct xfs_defer_op_type xfs_refcount_update_defer_type = {
        .type           = XFS_DEFER_OPS_TYPE_REFCOUNT,
        .max_items      = XFS_CUI_MAX_FAST_EXTENTS,
        .diff_items     = xfs_refcount_update_diff_items,
        .create_intent  = xfs_refcount_update_create_intent,
        .abort_intent   = xfs_refcount_update_abort_intent,
        .log_item       = xfs_refcount_update_log_item,
        .create_done    = xfs_refcount_update_create_done,
        .finish_item    = xfs_refcount_update_finish_item,
        .finish_cleanup = xfs_refcount_update_finish_cleanup,
        .cancel_item    = xfs_refcount_update_cancel_item,
};

/* Register the deferred op type. */
void
xfs_refcount_update_init_defer_op(void)
{
        xfs_defer_init_op_type(&xfs_refcount_update_defer_type);
}