mm: fix exec activate_mm vs TLB shootdown and lazy tlb switching race

[linux/fpc-iii.git] / fs / xfs / xfs_dquot_item.c

/*
 * Copyright (c) 2000-2003 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * 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.
 *
 * 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_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_error.h"
#include "xfs_trans.h"
#include "xfs_buf_item.h"
#include "xfs_trans_priv.h"
#include "xfs_qm.h"
#include "xfs_log.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 xfs_log_vec      *lv)
{
        struct xfs_dq_logitem   *qlip = DQUOT_ITEM(lip);
        struct xfs_log_iovec    *vecp = NULL;
        struct xfs_dq_logformat *qlf;

        qlf = xlog_prepare_iovec(lv, &vecp, XLOG_REG_TYPE_QFORMAT);
        qlf->qlf_type = XFS_LI_DQUOT;
        qlf->qlf_size = 2;
        qlf->qlf_id = be32_to_cpu(qlip->qli_dquot->q_core.d_id);
        qlf->qlf_blkno = qlip->qli_dquot->q_blkno;
        qlf->qlf_len = 1;
        qlf->qlf_boffset = qlip->qli_dquot->q_bufoffset;
        xlog_finish_iovec(lv, vecp, sizeof(struct xfs_dq_logformat));

        xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_DQUOT,
                        &qlip->qli_dquot->q_core,
                        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);
}

STATIC xfs_lsn_t
xfs_qm_dquot_logitem_committed(
        struct xfs_log_item     *lip,
        xfs_lsn_t               lsn)
{
        /*
         * We always re-log the entire dquot when it becomes dirty,
         * so, the latest copy _is_ the only one that matters.
         */
        return lsn;
}

/*
 * 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));
}

/*
 * Callback used to mark a buffer with XFS_LI_FAILED when items in the buffer
 * have been failed during writeback
 *
 * this informs the AIL that the dquot is already flush locked on the next push,
 * and acquires a hold on the buffer to ensure that it isn't reclaimed before
 * dirty data makes it to disk.
 */
STATIC void
xfs_dquot_item_error(
        struct xfs_log_item     *lip,
        struct xfs_buf          *bp)
{
        struct xfs_dquot        *dqp;

        dqp = DQUOT_ITEM(lip)->qli_dquot;
        ASSERT(!completion_done(&dqp->q_flush));
        xfs_set_li_failed(lip, bp);
}

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

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

        /*
         * The buffer containing this item failed to be written back
         * previously. Resubmit the buffer for IO
         */
        if (lip->li_flags & XFS_LI_FAILED) {
                if (!xfs_buf_trylock(bp))
                        return XFS_ITEM_LOCKED;

                if (!xfs_buf_resubmit_failed_buffers(bp, lip, buffer_list))
                        rval = XFS_ITEM_FLUSHING;

                xfs_buf_unlock(bp);
                return rval;
        }

        if (!xfs_dqlock_nowait(dqp))
                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(&lip->li_ailp->xa_lock);

        error = xfs_qm_dqflush(dqp, &bp);
        if (error) {
                xfs_warn(dqp->q_mount, "%s: push error %d on dqp %p",
                        __func__, error, dqp);
        } else {
                if (!xfs_buf_delwri_queue(bp, buffer_list))
                        rval = XFS_ITEM_FLUSHING;
                xfs_buf_relse(bp);
        }

        spin_lock(&lip->li_ailp->xa_lock);
out_unlock:
        xfs_dqunlock(dqp);
        return rval;
}

/*
 * Unlock the dquot associated with the log item.
 * Clear the fields of the dquot and dquot log item that
 * are specific to the current transaction.  If the
 * hold flags is set, do not unlock the dquot.
 */
STATIC void
xfs_qm_dquot_logitem_unlock(
        struct xfs_log_item     *lip)
{
        struct xfs_dquot        *dqp = DQUOT_ITEM(lip)->qli_dquot;

        ASSERT(XFS_DQ_IS_LOCKED(dqp));

        /*
         * Clear the transaction pointer in the dquot
         */
        dqp->q_transp = NULL;

        /*
         * 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.
         */
        xfs_dqunlock(dqp);
}

/*
 * this needs to stamp an lsn into the dquot, I think.
 * rpc's that look at user dquot's would then have to
 * push on the dependency recorded in the dquot
 */
STATIC void
xfs_qm_dquot_logitem_committing(
        struct xfs_log_item     *lip,
        xfs_lsn_t               lsn)
{
}

/*
 * This is the ops vector for dquots
 */
static const struct xfs_item_ops xfs_dquot_item_ops = {
        .iop_size       = xfs_qm_dquot_logitem_size,
        .iop_format     = xfs_qm_dquot_logitem_format,
        .iop_pin        = xfs_qm_dquot_logitem_pin,
        .iop_unpin      = xfs_qm_dquot_logitem_unpin,
        .iop_unlock     = xfs_qm_dquot_logitem_unlock,
        .iop_committed  = xfs_qm_dquot_logitem_committed,
        .iop_push       = xfs_qm_dquot_logitem_push,
        .iop_committing = xfs_qm_dquot_logitem_committing,
        .iop_error      = xfs_dquot_item_error
};

/*
 * 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);
        lp->qli_dquot = dqp;
}

/*------------------  QUOTAOFF LOG ITEMS  -------------------*/

static inline struct xfs_qoff_logitem *QOFF_ITEM(struct xfs_log_item *lip)
{
        return container_of(lip, struct xfs_qoff_logitem, qql_item);
}


/*
 * This returns the number of iovecs needed to log the given quotaoff item.
 * We only need 1 iovec for an quotaoff item.  It just logs the
 * quotaoff_log_format structure.
 */
STATIC void
xfs_qm_qoff_logitem_size(
        struct xfs_log_item     *lip,
        int                     *nvecs,
        int                     *nbytes)
{
        *nvecs += 1;
        *nbytes += sizeof(struct xfs_qoff_logitem);
}

STATIC void
xfs_qm_qoff_logitem_format(
        struct xfs_log_item     *lip,
        struct xfs_log_vec      *lv)
{
        struct xfs_qoff_logitem *qflip = QOFF_ITEM(lip);
        struct xfs_log_iovec    *vecp = NULL;
        struct xfs_qoff_logformat *qlf;

        qlf = xlog_prepare_iovec(lv, &vecp, XLOG_REG_TYPE_QUOTAOFF);
        qlf->qf_type = XFS_LI_QUOTAOFF;
        qlf->qf_size = 1;
        qlf->qf_flags = qflip->qql_flags;
        xlog_finish_iovec(lv, vecp, sizeof(struct xfs_qoff_logitem));
}

/*
 * Pinning has no meaning for an quotaoff item, so just return.
 */
STATIC void
xfs_qm_qoff_logitem_pin(
        struct xfs_log_item     *lip)
{
}

/*
 * Since pinning has no meaning for an quotaoff item, unpinning does
 * not either.
 */
STATIC void
xfs_qm_qoff_logitem_unpin(
        struct xfs_log_item     *lip,
        int                     remove)
{
}

/*
 * There isn't much you can do to push a quotaoff item.  It is simply
 * stuck waiting for the log to be flushed to disk.
 */
STATIC uint
xfs_qm_qoff_logitem_push(
        struct xfs_log_item     *lip,
        struct list_head        *buffer_list)
{
        return XFS_ITEM_LOCKED;
}

/*
 * Quotaoff items have no locking or pushing, so return failure
 * so that the caller doesn't bother with us.
 */
STATIC void
xfs_qm_qoff_logitem_unlock(
        struct xfs_log_item     *lip)
{
}

/*
 * The quotaoff-start-item is logged only once and cannot be moved in the log,
 * so simply return the lsn at which it's been logged.
 */
STATIC xfs_lsn_t
xfs_qm_qoff_logitem_committed(
        struct xfs_log_item     *lip,
        xfs_lsn_t               lsn)
{
        return lsn;
}

STATIC xfs_lsn_t
xfs_qm_qoffend_logitem_committed(
        struct xfs_log_item     *lip,
        xfs_lsn_t               lsn)
{
        struct xfs_qoff_logitem *qfe = QOFF_ITEM(lip);
        struct xfs_qoff_logitem *qfs = qfe->qql_start_lip;
        struct xfs_ail          *ailp = qfs->qql_item.li_ailp;

        /*
         * Delete the qoff-start logitem from the AIL.
         * xfs_trans_ail_delete() drops the AIL lock.
         */
        spin_lock(&ailp->xa_lock);
        xfs_trans_ail_delete(ailp, &qfs->qql_item, SHUTDOWN_LOG_IO_ERROR);

        kmem_free(qfs->qql_item.li_lv_shadow);
        kmem_free(lip->li_lv_shadow);
        kmem_free(qfs);
        kmem_free(qfe);
        return (xfs_lsn_t)-1;
}

/*
 * XXX rcc - don't know quite what to do with this.  I think we can
 * just ignore it.  The only time that isn't the case is if we allow
 * the client to somehow see that quotas have been turned off in which
 * we can't allow that to get back until the quotaoff hits the disk.
 * So how would that happen?  Also, do we need different routines for
 * quotaoff start and quotaoff end?  I suspect the answer is yes but
 * to be sure, I need to look at the recovery code and see how quota off
 * recovery is handled (do we roll forward or back or do something else).
 * If we roll forwards or backwards, then we need two separate routines,
 * one that does nothing and one that stamps in the lsn that matters
 * (truly makes the quotaoff irrevocable).  If we do something else,
 * then maybe we don't need two.
 */
STATIC void
xfs_qm_qoff_logitem_committing(
        struct xfs_log_item     *lip,
        xfs_lsn_t               commit_lsn)
{
}

static const struct xfs_item_ops xfs_qm_qoffend_logitem_ops = {
        .iop_size       = xfs_qm_qoff_logitem_size,
        .iop_format     = xfs_qm_qoff_logitem_format,
        .iop_pin        = xfs_qm_qoff_logitem_pin,
        .iop_unpin      = xfs_qm_qoff_logitem_unpin,
        .iop_unlock     = xfs_qm_qoff_logitem_unlock,
        .iop_committed  = xfs_qm_qoffend_logitem_committed,
        .iop_push       = xfs_qm_qoff_logitem_push,
        .iop_committing = xfs_qm_qoff_logitem_committing
};

/*
 * This is the ops vector shared by all quotaoff-start log items.
 */
static const struct xfs_item_ops xfs_qm_qoff_logitem_ops = {
        .iop_size       = xfs_qm_qoff_logitem_size,
        .iop_format     = xfs_qm_qoff_logitem_format,
        .iop_pin        = xfs_qm_qoff_logitem_pin,
        .iop_unpin      = xfs_qm_qoff_logitem_unpin,
        .iop_unlock     = xfs_qm_qoff_logitem_unlock,
        .iop_committed  = xfs_qm_qoff_logitem_committed,
        .iop_push       = xfs_qm_qoff_logitem_push,
        .iop_committing = xfs_qm_qoff_logitem_committing
};

/*
 * Allocate and initialize an quotaoff item of the correct quota type(s).
 */
struct xfs_qoff_logitem *
xfs_qm_qoff_logitem_init(
        struct xfs_mount        *mp,
        struct xfs_qoff_logitem *start,
        uint                    flags)
{
        struct xfs_qoff_logitem *qf;

        qf = kmem_zalloc(sizeof(struct xfs_qoff_logitem), KM_SLEEP);

        xfs_log_item_init(mp, &qf->qql_item, XFS_LI_QUOTAOFF, start ?
                        &xfs_qm_qoffend_logitem_ops : &xfs_qm_qoff_logitem_ops);
        qf->qql_item.li_mountp = mp;
        qf->qql_start_lip = start;
        qf->qql_flags = flags;
        return qf;
}