// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2000-2003 Silicon Graphics, Inc.
 * All Rights Reserved.
 */
#include "xfs_platform.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_inode.h"
#include "xfs_quota.h"
#include "xfs_trans.h"
#include "xfs_buf_item.h"
#include "xfs_trans_priv.h"
#include "xfs_qm.h"
#include "xfs_log.h"
#include "xfs_error.h"

static inline struct xfs_dq_logitem *DQUOT_ITEM(struct xfs_log_item *lip)
{
        return container_of(lip, struct xfs_dq_logitem, qli_item);
}

/*
 * returns the number of iovecs needed to log the given dquot item.
 */
STATIC void
xfs_qm_dquot_logitem_size(
        struct xfs_log_item     *lip,
        int                     *nvecs,
        int                     *nbytes)
{
        *nvecs += 2;
        *nbytes += sizeof(struct xfs_dq_logformat) +
                   sizeof(struct xfs_disk_dquot);
}

/*
 * fills in the vector of log iovecs for the given dquot log item.
 */
STATIC void
xfs_qm_dquot_logitem_format(
        struct xfs_log_item     *lip,
        struct xlog_format_buf  *lfb)
{
        struct xfs_disk_dquot   ddq;
        struct xfs_dq_logitem   *qlip = DQUOT_ITEM(lip);
        struct xfs_dq_logformat *qlf;

        qlf = xlog_format_start(lfb, XLOG_REG_TYPE_QFORMAT);
        qlf->qlf_type = XFS_LI_DQUOT;
        qlf->qlf_size = 2;
        qlf->qlf_id = qlip->qli_dquot->q_id;
        qlf->qlf_blkno = qlip->qli_dquot->q_blkno;
        qlf->qlf_len = 1;
        qlf->qlf_boffset = qlip->qli_dquot->q_bufoffset;
        xlog_format_commit(lfb, sizeof(struct xfs_dq_logformat));

        xfs_dquot_to_disk(&ddq, qlip->qli_dquot);

        xlog_format_copy(lfb, XLOG_REG_TYPE_DQUOT, &ddq,
                        sizeof(struct xfs_disk_dquot));
}

/*
 * Increment the pin count of the given dquot.
 */
STATIC void
xfs_qm_dquot_logitem_pin(
        struct xfs_log_item     *lip)
{
        struct xfs_dquot        *dqp = DQUOT_ITEM(lip)->qli_dquot;

        ASSERT(XFS_DQ_IS_LOCKED(dqp));
        atomic_inc(&dqp->q_pincount);
}

/*
 * Decrement the pin count of the given dquot, and wake up
 * anyone in xfs_dqwait_unpin() if the count goes to 0.  The
 * dquot must have been previously pinned with a call to
 * xfs_qm_dquot_logitem_pin().
 */
STATIC void
xfs_qm_dquot_logitem_unpin(
        struct xfs_log_item     *lip,
        int                     remove)
{
        struct xfs_dquot        *dqp = DQUOT_ITEM(lip)->qli_dquot;

        ASSERT(atomic_read(&dqp->q_pincount) > 0);
        if (atomic_dec_and_test(&dqp->q_pincount))
                wake_up(&dqp->q_pinwait);
}

/*
 * This is called to wait for the given dquot to be unpinned.
 * Most of these pin/unpin routines are plagiarized from inode code.
 */
void
xfs_qm_dqunpin_wait(
        struct xfs_dquot        *dqp)
{
        ASSERT(XFS_DQ_IS_LOCKED(dqp));
        if (atomic_read(&dqp->q_pincount) == 0)
                return;

        /*
         * Give the log a push so we don't wait here too long.
         */
        xfs_log_force(dqp->q_mount, 0);
        wait_event(dqp->q_pinwait, (atomic_read(&dqp->q_pincount) == 0));
}

STATIC uint
xfs_qm_dquot_logitem_push(
        struct xfs_log_item     *lip,
        struct list_head        *buffer_list)
                __releases(&lip->li_ailp->ail_lock)
                __acquires(&lip->li_ailp->ail_lock)
{
        struct xfs_dq_logitem   *qlip = DQUOT_ITEM(lip);
        struct xfs_dquot        *dqp = qlip->qli_dquot;
        struct xfs_buf          *bp;
        struct xfs_ail          *ailp = lip->li_ailp;
        uint                    rval = XFS_ITEM_SUCCESS;
        int                     error;

        if (atomic_read(&dqp->q_pincount) > 0)
                return XFS_ITEM_PINNED;

        if (!mutex_trylock(&dqp->q_qlock))
                return XFS_ITEM_LOCKED;

        /*
         * Re-check the pincount now that we stabilized the value by
         * taking the quota lock.
         */
        if (atomic_read(&dqp->q_pincount) > 0) {
                rval = XFS_ITEM_PINNED;
                goto out_unlock;
        }

        /*
         * Someone else is already flushing the dquot.  Nothing we can do
         * here but wait for the flush to finish and remove the item from
         * the AIL.
         */
        if (!xfs_dqflock_nowait(dqp)) {
                rval = XFS_ITEM_FLUSHING;
                goto out_unlock;
        }

        spin_unlock(&ailp->ail_lock);

        error = xfs_dquot_use_attached_buf(dqp, &bp);
        if (error == -EAGAIN) {
                xfs_dqfunlock(dqp);
                rval = XFS_ITEM_LOCKED;
                goto out_relock_ail;
        }

        /*
         * dqflush completes dqflock on error, and the delwri ioend does it on
         * success.
         */
        error = xfs_qm_dqflush(dqp, bp);
        if (!error) {
                if (!xfs_buf_delwri_queue(bp, buffer_list))
                        rval = XFS_ITEM_FLUSHING;
        }
        xfs_buf_relse(bp);
        /*
         * The buffer no longer protects the log item from reclaim, so
         * do not reference lip after this point.
         */

out_relock_ail:
        spin_lock(&ailp->ail_lock);
out_unlock:
        mutex_unlock(&dqp->q_qlock);
        return rval;
}

STATIC void
xfs_qm_dquot_logitem_release(
        struct xfs_log_item     *lip)
{
        struct xfs_dquot        *dqp = DQUOT_ITEM(lip)->qli_dquot;

        ASSERT(XFS_DQ_IS_LOCKED(dqp));

        /*
         * dquots are never 'held' from getting unlocked at the end of
         * a transaction.  Their locking and unlocking is hidden inside the
         * transaction layer, within trans_commit. Hence, no LI_HOLD flag
         * for the logitem.
         */
        mutex_unlock(&dqp->q_qlock);
}

STATIC void
xfs_qm_dquot_logitem_committing(
        struct xfs_log_item     *lip,
        xfs_csn_t               seq)
{
        return xfs_qm_dquot_logitem_release(lip);
}

#ifdef DEBUG_EXPENSIVE
static void
xfs_qm_dquot_logitem_precommit_check(
        struct xfs_dquot        *dqp)
{
        struct xfs_mount        *mp = dqp->q_mount;
        struct xfs_disk_dquot   ddq = { };
        xfs_failaddr_t          fa;

        xfs_dquot_to_disk(&ddq, dqp);
        fa = xfs_dquot_verify(mp, &ddq, dqp->q_id);
        if (fa) {
                XFS_CORRUPTION_ERROR("Bad dquot during logging",
                                XFS_ERRLEVEL_LOW, mp, &ddq, sizeof(ddq));
                xfs_alert(mp,
 "Metadata corruption detected at %pS, dquot 0x%x",
                                fa, dqp->q_id);
                xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
                ASSERT(fa == NULL);
        }
}
#else
# define xfs_qm_dquot_logitem_precommit_check(...)      ((void)0)
#endif

static int
xfs_qm_dquot_logitem_precommit(
        struct xfs_trans        *tp,
        struct xfs_log_item     *lip)
{
        struct xfs_dq_logitem   *qlip = DQUOT_ITEM(lip);
        struct xfs_dquot        *dqp = qlip->qli_dquot;

        xfs_qm_dquot_logitem_precommit_check(dqp);

        return xfs_dquot_attach_buf(tp, dqp);
}

static const struct xfs_item_ops xfs_dquot_item_ops = {
        .iop_size       = xfs_qm_dquot_logitem_size,
        .iop_precommit  = xfs_qm_dquot_logitem_precommit,
        .iop_format     = xfs_qm_dquot_logitem_format,
        .iop_pin        = xfs_qm_dquot_logitem_pin,
        .iop_unpin      = xfs_qm_dquot_logitem_unpin,
        .iop_release    = xfs_qm_dquot_logitem_release,
        .iop_committing = xfs_qm_dquot_logitem_committing,
        .iop_push       = xfs_qm_dquot_logitem_push,
};

/*
 * Initialize the dquot log item for a newly allocated dquot.
 * The dquot isn't locked at this point, but it isn't on any of the lists
 * either, so we don't care.
 */
void
xfs_qm_dquot_logitem_init(
        struct xfs_dquot        *dqp)
{
        struct xfs_dq_logitem   *lp = &dqp->q_logitem;

        xfs_log_item_init(dqp->q_mount, &lp->qli_item, XFS_LI_DQUOT,
                                        &xfs_dquot_item_ops);
        spin_lock_init(&lp->qli_lock);
        lp->qli_dquot = dqp;
        lp->qli_dirty = false;
}