arm64: kgdb: Fix single-step exception handling oops

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

/*
 * 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_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_bit.h"
#include "xfs_mount.h"
#include "xfs_defer.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_trans_priv.h"
#include "xfs_buf_item.h"
#include "xfs_bmap_item.h"
#include "xfs_log.h"
#include "xfs_bmap.h"
#include "xfs_icache.h"
#include "xfs_trace.h"
#include "xfs_bmap_btree.h"
#include "xfs_trans_space.h"


kmem_zone_t     *xfs_bui_zone;
kmem_zone_t     *xfs_bud_zone;

static inline struct xfs_bui_log_item *BUI_ITEM(struct xfs_log_item *lip)
{
        return container_of(lip, struct xfs_bui_log_item, bui_item);
}

void
xfs_bui_item_free(
        struct xfs_bui_log_item *buip)
{
        kmem_zone_free(xfs_bui_zone, buip);
}

STATIC void
xfs_bui_item_size(
        struct xfs_log_item     *lip,
        int                     *nvecs,
        int                     *nbytes)
{
        struct xfs_bui_log_item *buip = BUI_ITEM(lip);

        *nvecs += 1;
        *nbytes += xfs_bui_log_format_sizeof(buip->bui_format.bui_nextents);
}

/*
 * This is called to fill in the vector of log iovecs for the
 * given bui log item. We use only 1 iovec, and we point that
 * at the bui_log_format structure embedded in the bui item.
 * It is at this point that we assert that all of the extent
 * slots in the bui item have been filled.
 */
STATIC void
xfs_bui_item_format(
        struct xfs_log_item     *lip,
        struct xfs_log_vec      *lv)
{
        struct xfs_bui_log_item *buip = BUI_ITEM(lip);
        struct xfs_log_iovec    *vecp = NULL;

        ASSERT(atomic_read(&buip->bui_next_extent) ==
                        buip->bui_format.bui_nextents);

        buip->bui_format.bui_type = XFS_LI_BUI;
        buip->bui_format.bui_size = 1;

        xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_BUI_FORMAT, &buip->bui_format,
                        xfs_bui_log_format_sizeof(buip->bui_format.bui_nextents));
}

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

/*
 * The unpin operation is the last place an BUI is manipulated in the log. It is
 * either inserted in the AIL or aborted in the event of a log I/O error. In
 * either case, the BUI transaction has been successfully committed to make it
 * this far. Therefore, we expect whoever committed the BUI to either construct
 * and commit the BUD or drop the BUD's reference in the event of error. Simply
 * drop the log's BUI reference now that the log is done with it.
 */
STATIC void
xfs_bui_item_unpin(
        struct xfs_log_item     *lip,
        int                     remove)
{
        struct xfs_bui_log_item *buip = BUI_ITEM(lip);

        xfs_bui_release(buip);
}

/*
 * BUI items have no locking or pushing.  However, since BUIs are pulled from
 * the AIL when their corresponding BUDs are committed to disk, their situation
 * is very similar to being pinned.  Return XFS_ITEM_PINNED so that the caller
 * will eventually flush the log.  This should help in getting the BUI out of
 * the AIL.
 */
STATIC uint
xfs_bui_item_push(
        struct xfs_log_item     *lip,
        struct list_head        *buffer_list)
{
        return XFS_ITEM_PINNED;
}

/*
 * The BUI has been either committed or aborted if the transaction has been
 * cancelled. If the transaction was cancelled, an BUD isn't going to be
 * constructed and thus we free the BUI here directly.
 */
STATIC void
xfs_bui_item_unlock(
        struct xfs_log_item     *lip)
{
        if (lip->li_flags & XFS_LI_ABORTED)
                xfs_bui_item_free(BUI_ITEM(lip));
}

/*
 * The BUI 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_bui_item_committed(
        struct xfs_log_item     *lip,
        xfs_lsn_t               lsn)
{
        return lsn;
}

/*
 * The BUI dependency tracking op doesn't do squat.  It can't because
 * it doesn't know where the free extent is coming from.  The dependency
 * tracking has to be handled by the "enclosing" metadata object.  For
 * example, for inodes, the inode is locked throughout the extent freeing
 * so the dependency should be recorded there.
 */
STATIC void
xfs_bui_item_committing(
        struct xfs_log_item     *lip,
        xfs_lsn_t               lsn)
{
}

/*
 * This is the ops vector shared by all bui log items.
 */
static const struct xfs_item_ops xfs_bui_item_ops = {
        .iop_size       = xfs_bui_item_size,
        .iop_format     = xfs_bui_item_format,
        .iop_pin        = xfs_bui_item_pin,
        .iop_unpin      = xfs_bui_item_unpin,
        .iop_unlock     = xfs_bui_item_unlock,
        .iop_committed  = xfs_bui_item_committed,
        .iop_push       = xfs_bui_item_push,
        .iop_committing = xfs_bui_item_committing,
};

/*
 * Allocate and initialize an bui item with the given number of extents.
 */
struct xfs_bui_log_item *
xfs_bui_init(
        struct xfs_mount                *mp)

{
        struct xfs_bui_log_item         *buip;

        buip = kmem_zone_zalloc(xfs_bui_zone, KM_SLEEP);

        xfs_log_item_init(mp, &buip->bui_item, XFS_LI_BUI, &xfs_bui_item_ops);
        buip->bui_format.bui_nextents = XFS_BUI_MAX_FAST_EXTENTS;
        buip->bui_format.bui_id = (uintptr_t)(void *)buip;
        atomic_set(&buip->bui_next_extent, 0);
        atomic_set(&buip->bui_refcount, 2);

        return buip;
}

/*
 * Freeing the BUI requires that we remove it from the AIL if it has already
 * been placed there. However, the BUI may not yet have been placed in the AIL
 * when called by xfs_bui_release() from BUD processing due to the ordering of
 * committed vs unpin operations in bulk insert operations. Hence the reference
 * count to ensure only the last caller frees the BUI.
 */
void
xfs_bui_release(
        struct xfs_bui_log_item *buip)
{
        if (atomic_dec_and_test(&buip->bui_refcount)) {
                xfs_trans_ail_remove(&buip->bui_item, SHUTDOWN_LOG_IO_ERROR);
                xfs_bui_item_free(buip);
        }
}

static inline struct xfs_bud_log_item *BUD_ITEM(struct xfs_log_item *lip)
{
        return container_of(lip, struct xfs_bud_log_item, bud_item);
}

STATIC void
xfs_bud_item_size(
        struct xfs_log_item     *lip,
        int                     *nvecs,
        int                     *nbytes)
{
        *nvecs += 1;
        *nbytes += sizeof(struct xfs_bud_log_format);
}

/*
 * This is called to fill in the vector of log iovecs for the
 * given bud log item. We use only 1 iovec, and we point that
 * at the bud_log_format structure embedded in the bud item.
 * It is at this point that we assert that all of the extent
 * slots in the bud item have been filled.
 */
STATIC void
xfs_bud_item_format(
        struct xfs_log_item     *lip,
        struct xfs_log_vec      *lv)
{
        struct xfs_bud_log_item *budp = BUD_ITEM(lip);
        struct xfs_log_iovec    *vecp = NULL;

        budp->bud_format.bud_type = XFS_LI_BUD;
        budp->bud_format.bud_size = 1;

        xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_BUD_FORMAT, &budp->bud_format,
                        sizeof(struct xfs_bud_log_format));
}

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

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

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

/*
 * The BUD is either committed or aborted if the transaction is cancelled. If
 * the transaction is cancelled, drop our reference to the BUI and free the
 * BUD.
 */
STATIC void
xfs_bud_item_unlock(
        struct xfs_log_item     *lip)
{
        struct xfs_bud_log_item *budp = BUD_ITEM(lip);

        if (lip->li_flags & XFS_LI_ABORTED) {
                xfs_bui_release(budp->bud_buip);
                kmem_zone_free(xfs_bud_zone, budp);
        }
}

/*
 * When the bud item is committed to disk, all we need to do is delete our
 * reference to our partner bui item and then free ourselves. Since we're
 * freeing ourselves we must return -1 to keep the transaction code from
 * further referencing this item.
 */
STATIC xfs_lsn_t
xfs_bud_item_committed(
        struct xfs_log_item     *lip,
        xfs_lsn_t               lsn)
{
        struct xfs_bud_log_item *budp = BUD_ITEM(lip);

        /*
         * Drop the BUI reference regardless of whether the BUD has been
         * aborted. Once the BUD transaction is constructed, it is the sole
         * responsibility of the BUD to release the BUI (even if the BUI is
         * aborted due to log I/O error).
         */
        xfs_bui_release(budp->bud_buip);
        kmem_zone_free(xfs_bud_zone, budp);

        return (xfs_lsn_t)-1;
}

/*
 * The BUD dependency tracking op doesn't do squat.  It can't because
 * it doesn't know where the free extent is coming from.  The dependency
 * tracking has to be handled by the "enclosing" metadata object.  For
 * example, for inodes, the inode is locked throughout the extent freeing
 * so the dependency should be recorded there.
 */
STATIC void
xfs_bud_item_committing(
        struct xfs_log_item     *lip,
        xfs_lsn_t               lsn)
{
}

/*
 * This is the ops vector shared by all bud log items.
 */
static const struct xfs_item_ops xfs_bud_item_ops = {
        .iop_size       = xfs_bud_item_size,
        .iop_format     = xfs_bud_item_format,
        .iop_pin        = xfs_bud_item_pin,
        .iop_unpin      = xfs_bud_item_unpin,
        .iop_unlock     = xfs_bud_item_unlock,
        .iop_committed  = xfs_bud_item_committed,
        .iop_push       = xfs_bud_item_push,
        .iop_committing = xfs_bud_item_committing,
};

/*
 * Allocate and initialize an bud item with the given number of extents.
 */
struct xfs_bud_log_item *
xfs_bud_init(
        struct xfs_mount                *mp,
        struct xfs_bui_log_item         *buip)

{
        struct xfs_bud_log_item *budp;

        budp = kmem_zone_zalloc(xfs_bud_zone, KM_SLEEP);
        xfs_log_item_init(mp, &budp->bud_item, XFS_LI_BUD, &xfs_bud_item_ops);
        budp->bud_buip = buip;
        budp->bud_format.bud_bui_id = buip->bui_format.bui_id;

        return budp;
}

/*
 * Process a bmap update intent item that was recovered from the log.
 * We need to update some inode's bmbt.
 */
int
xfs_bui_recover(
        struct xfs_mount                *mp,
        struct xfs_bui_log_item         *buip)
{
        int                             error = 0;
        unsigned int                    bui_type;
        struct xfs_map_extent           *bmap;
        xfs_fsblock_t                   startblock_fsb;
        xfs_fsblock_t                   inode_fsb;
        xfs_filblks_t                   count;
        bool                            op_ok;
        struct xfs_bud_log_item         *budp;
        enum xfs_bmap_intent_type       type;
        int                             whichfork;
        xfs_exntst_t                    state;
        struct xfs_trans                *tp;
        struct xfs_inode                *ip = NULL;
        struct xfs_defer_ops            dfops;
        struct xfs_bmbt_irec            irec;
        xfs_fsblock_t                   firstfsb;

        ASSERT(!test_bit(XFS_BUI_RECOVERED, &buip->bui_flags));

        /* Only one mapping operation per BUI... */
        if (buip->bui_format.bui_nextents != XFS_BUI_MAX_FAST_EXTENTS) {
                set_bit(XFS_BUI_RECOVERED, &buip->bui_flags);
                xfs_bui_release(buip);
                return -EIO;
        }

        /*
         * First check the validity of the extent described by the
         * BUI.  If anything is bad, then toss the BUI.
         */
        bmap = &buip->bui_format.bui_extents[0];
        startblock_fsb = XFS_BB_TO_FSB(mp,
                           XFS_FSB_TO_DADDR(mp, bmap->me_startblock));
        inode_fsb = XFS_BB_TO_FSB(mp, XFS_FSB_TO_DADDR(mp,
                        XFS_INO_TO_FSB(mp, bmap->me_owner)));
        switch (bmap->me_flags & XFS_BMAP_EXTENT_TYPE_MASK) {
        case XFS_BMAP_MAP:
        case XFS_BMAP_UNMAP:
                op_ok = true;
                break;
        default:
                op_ok = false;
                break;
        }
        if (!op_ok || startblock_fsb == 0 ||
            bmap->me_len == 0 ||
            inode_fsb == 0 ||
            startblock_fsb >= mp->m_sb.sb_dblocks ||
            bmap->me_len >= mp->m_sb.sb_agblocks ||
            inode_fsb >= mp->m_sb.sb_dblocks ||
            (bmap->me_flags & ~XFS_BMAP_EXTENT_FLAGS)) {
                /*
                 * This will pull the BUI from the AIL and
                 * free the memory associated with it.
                 */
                set_bit(XFS_BUI_RECOVERED, &buip->bui_flags);
                xfs_bui_release(buip);
                return -EIO;
        }

        error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate,
                        XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK), 0, 0, &tp);
        if (error)
                return error;
        budp = xfs_trans_get_bud(tp, buip);

        /* Grab the inode. */
        error = xfs_iget(mp, tp, bmap->me_owner, 0, XFS_ILOCK_EXCL, &ip);
        if (error)
                goto err_inode;

        if (VFS_I(ip)->i_nlink == 0)
                xfs_iflags_set(ip, XFS_IRECOVERY);
        xfs_defer_init(&dfops, &firstfsb);

        /* Process deferred bmap item. */
        state = (bmap->me_flags & XFS_BMAP_EXTENT_UNWRITTEN) ?
                        XFS_EXT_UNWRITTEN : XFS_EXT_NORM;
        whichfork = (bmap->me_flags & XFS_BMAP_EXTENT_ATTR_FORK) ?
                        XFS_ATTR_FORK : XFS_DATA_FORK;
        bui_type = bmap->me_flags & XFS_BMAP_EXTENT_TYPE_MASK;
        switch (bui_type) {
        case XFS_BMAP_MAP:
        case XFS_BMAP_UNMAP:
                type = bui_type;
                break;
        default:
                error = -EFSCORRUPTED;
                goto err_dfops;
        }
        xfs_trans_ijoin(tp, ip, 0);

        count = bmap->me_len;
        error = xfs_trans_log_finish_bmap_update(tp, budp, &dfops, type,
                        ip, whichfork, bmap->me_startoff,
                        bmap->me_startblock, &count, state);
        if (error)
                goto err_dfops;

        if (count > 0) {
                ASSERT(type == XFS_BMAP_UNMAP);
                irec.br_startblock = bmap->me_startblock;
                irec.br_blockcount = count;
                irec.br_startoff = bmap->me_startoff;
                irec.br_state = state;
                error = xfs_bmap_unmap_extent(tp->t_mountp, &dfops, ip, &irec);
                if (error)
                        goto err_dfops;
        }

        /* Finish transaction, free inodes. */
        error = xfs_defer_finish(&tp, &dfops, NULL);
        if (error)
                goto err_dfops;

        set_bit(XFS_BUI_RECOVERED, &buip->bui_flags);
        error = xfs_trans_commit(tp);
        xfs_iunlock(ip, XFS_ILOCK_EXCL);
        IRELE(ip);

        return error;

err_dfops:
        xfs_defer_cancel(&dfops);
err_inode:
        xfs_trans_cancel(tp);
        if (ip) {
                xfs_iunlock(ip, XFS_ILOCK_EXCL);
                IRELE(ip);
        }
        return error;
}