[PATCH] Kexec: Kexec on panic fix with nmi watchdog enabled

[linux-2.6/sactl.git] / fs / xfs / xfs_extfree_item.c

/*
 * Copyright (c) 2000-2001 Silicon Graphics, Inc.  All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2 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.
 *
 * Further, this software is distributed without any warranty that it is
 * free of the rightful claim of any third person regarding infringement
 * or the like.  Any license provided herein, whether implied or
 * otherwise, applies only to this software file.  Patent licenses, if
 * any, provided herein do not apply to combinations of this program with
 * other software, or any other product whatsoever.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write the Free Software Foundation, Inc., 59
 * Temple Place - Suite 330, Boston MA 02111-1307, USA.
 *
 * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
 * Mountain View, CA  94043, or:
 *
 * http://www.sgi.com
 *
 * For further information regarding this notice, see:
 *
 * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
 */

/*
 * This file contains the implementation of the xfs_efi_log_item
 * and xfs_efd_log_item items.
 */

#include "xfs.h"

#include "xfs_macros.h"
#include "xfs_types.h"
#include "xfs_inum.h"
#include "xfs_log.h"
#include "xfs_trans.h"
#include "xfs_buf_item.h"
#include "xfs_sb.h"
#include "xfs_dir.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_trans_priv.h"
#include "xfs_extfree_item.h"


kmem_zone_t     *xfs_efi_zone;
kmem_zone_t     *xfs_efd_zone;

STATIC void     xfs_efi_item_unlock(xfs_efi_log_item_t *);
STATIC void     xfs_efi_item_abort(xfs_efi_log_item_t *);
STATIC void     xfs_efd_item_abort(xfs_efd_log_item_t *);


void
xfs_efi_item_free(xfs_efi_log_item_t *efip)
{
        int nexts = efip->efi_format.efi_nextents;

        if (nexts > XFS_EFI_MAX_FAST_EXTENTS) {
                kmem_free(efip, sizeof(xfs_efi_log_item_t) +
                                (nexts - 1) * sizeof(xfs_extent_t));
        } else {
                kmem_zone_free(xfs_efi_zone, efip);
        }
}

/*
 * This returns the number of iovecs needed to log the given efi item.
 * We only need 1 iovec for an efi item.  It just logs the efi_log_format
 * structure.
 */
/*ARGSUSED*/
STATIC uint
xfs_efi_item_size(xfs_efi_log_item_t *efip)
{
        return 1;
}

/*
 * This is called to fill in the vector of log iovecs for the
 * given efi log item. We use only 1 iovec, and we point that
 * at the efi_log_format structure embedded in the efi item.
 * It is at this point that we assert that all of the extent
 * slots in the efi item have been filled.
 */
STATIC void
xfs_efi_item_format(xfs_efi_log_item_t  *efip,
                    xfs_log_iovec_t     *log_vector)
{
        uint    size;

        ASSERT(efip->efi_next_extent == efip->efi_format.efi_nextents);

        efip->efi_format.efi_type = XFS_LI_EFI;

        size = sizeof(xfs_efi_log_format_t);
        size += (efip->efi_format.efi_nextents - 1) * sizeof(xfs_extent_t);
        efip->efi_format.efi_size = 1;

        log_vector->i_addr = (xfs_caddr_t)&(efip->efi_format);
        log_vector->i_len = size;
        ASSERT(size >= sizeof(xfs_efi_log_format_t));
}


/*
 * Pinning has no meaning for an efi item, so just return.
 */
/*ARGSUSED*/
STATIC void
xfs_efi_item_pin(xfs_efi_log_item_t *efip)
{
        return;
}


/*
 * While EFIs cannot really be pinned, the unpin operation is the
 * last place at which the EFI is manipulated during a transaction.
 * Here we coordinate with xfs_efi_cancel() to determine who gets to
 * free the EFI.
 */
/*ARGSUSED*/
STATIC void
xfs_efi_item_unpin(xfs_efi_log_item_t *efip, int stale)
{
        xfs_mount_t     *mp;
        SPLDECL(s);

        mp = efip->efi_item.li_mountp;
        AIL_LOCK(mp, s);
        if (efip->efi_flags & XFS_EFI_CANCELED) {
                /*
                 * xfs_trans_delete_ail() drops the AIL lock.
                 */
                xfs_trans_delete_ail(mp, (xfs_log_item_t *)efip, s);
                xfs_efi_item_free(efip);
        } else {
                efip->efi_flags |= XFS_EFI_COMMITTED;
                AIL_UNLOCK(mp, s);
        }
}

/*
 * like unpin only we have to also clear the xaction descriptor
 * pointing the log item if we free the item.  This routine duplicates
 * unpin because efi_flags is protected by the AIL lock.  Freeing
 * the descriptor and then calling unpin would force us to drop the AIL
 * lock which would open up a race condition.
 */
STATIC void
xfs_efi_item_unpin_remove(xfs_efi_log_item_t *efip, xfs_trans_t *tp)
{
        xfs_mount_t     *mp;
        xfs_log_item_desc_t     *lidp;
        SPLDECL(s);

        mp = efip->efi_item.li_mountp;
        AIL_LOCK(mp, s);
        if (efip->efi_flags & XFS_EFI_CANCELED) {
                /*
                 * free the xaction descriptor pointing to this item
                 */
                lidp = xfs_trans_find_item(tp, (xfs_log_item_t *) efip);
                xfs_trans_free_item(tp, lidp);
                /*
                 * pull the item off the AIL.
                 * xfs_trans_delete_ail() drops the AIL lock.
                 */
                xfs_trans_delete_ail(mp, (xfs_log_item_t *)efip, s);
                xfs_efi_item_free(efip);
        } else {
                efip->efi_flags |= XFS_EFI_COMMITTED;
                AIL_UNLOCK(mp, s);
        }
}

/*
 * Efi items have no locking or pushing.  However, since EFIs are
 * pulled from the AIL when their corresponding EFDs 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 EFI out of the AIL.
 */
/*ARGSUSED*/
STATIC uint
xfs_efi_item_trylock(xfs_efi_log_item_t *efip)
{
        return XFS_ITEM_PINNED;
}

/*
 * Efi items have no locking, so just return.
 */
/*ARGSUSED*/
STATIC void
xfs_efi_item_unlock(xfs_efi_log_item_t *efip)
{
        if (efip->efi_item.li_flags & XFS_LI_ABORTED)
                xfs_efi_item_abort(efip);
        return;
}

/*
 * The EFI is logged only once and cannot be moved in the log, so
 * simply return the lsn at which it's been logged.  The canceled
 * flag is not paid any attention here.  Checking for that is delayed
 * until the EFI is unpinned.
 */
/*ARGSUSED*/
STATIC xfs_lsn_t
xfs_efi_item_committed(xfs_efi_log_item_t *efip, xfs_lsn_t lsn)
{
        return lsn;
}

/*
 * This is called when the transaction logging the EFI is aborted.
 * Free up the EFI and return.  No need to clean up the slot for
 * the item in the transaction.  That was done by the unpin code
 * which is called prior to this routine in the abort/fs-shutdown path.
 */
STATIC void
xfs_efi_item_abort(xfs_efi_log_item_t *efip)
{
        xfs_efi_item_free(efip);
}

/*
 * There isn't much you can do to push on an efi item.  It is simply
 * stuck waiting for all of its corresponding efd items to be
 * committed to disk.
 */
/*ARGSUSED*/
STATIC void
xfs_efi_item_push(xfs_efi_log_item_t *efip)
{
        return;
}

/*
 * The EFI 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.
 */
/*ARGSUSED*/
STATIC void
xfs_efi_item_committing(xfs_efi_log_item_t *efip, xfs_lsn_t lsn)
{
        return;
}

/*
 * This is the ops vector shared by all efi log items.
 */
STATIC struct xfs_item_ops xfs_efi_item_ops = {
        .iop_size       = (uint(*)(xfs_log_item_t*))xfs_efi_item_size,
        .iop_format     = (void(*)(xfs_log_item_t*, xfs_log_iovec_t*))
                                        xfs_efi_item_format,
        .iop_pin        = (void(*)(xfs_log_item_t*))xfs_efi_item_pin,
        .iop_unpin      = (void(*)(xfs_log_item_t*, int))xfs_efi_item_unpin,
        .iop_unpin_remove = (void(*)(xfs_log_item_t*, xfs_trans_t *))
                                        xfs_efi_item_unpin_remove,
        .iop_trylock    = (uint(*)(xfs_log_item_t*))xfs_efi_item_trylock,
        .iop_unlock     = (void(*)(xfs_log_item_t*))xfs_efi_item_unlock,
        .iop_committed  = (xfs_lsn_t(*)(xfs_log_item_t*, xfs_lsn_t))
                                        xfs_efi_item_committed,
        .iop_push       = (void(*)(xfs_log_item_t*))xfs_efi_item_push,
        .iop_abort      = (void(*)(xfs_log_item_t*))xfs_efi_item_abort,
        .iop_pushbuf    = NULL,
        .iop_committing = (void(*)(xfs_log_item_t*, xfs_lsn_t))
                                        xfs_efi_item_committing
};


/*
 * Allocate and initialize an efi item with the given number of extents.
 */
xfs_efi_log_item_t *
xfs_efi_init(xfs_mount_t        *mp,
             uint               nextents)

{
        xfs_efi_log_item_t      *efip;
        uint                    size;

        ASSERT(nextents > 0);
        if (nextents > XFS_EFI_MAX_FAST_EXTENTS) {
                size = (uint)(sizeof(xfs_efi_log_item_t) +
                        ((nextents - 1) * sizeof(xfs_extent_t)));
                efip = (xfs_efi_log_item_t*)kmem_zalloc(size, KM_SLEEP);
        } else {
                efip = (xfs_efi_log_item_t*)kmem_zone_zalloc(xfs_efi_zone,
                                                             KM_SLEEP);
        }

        efip->efi_item.li_type = XFS_LI_EFI;
        efip->efi_item.li_ops = &xfs_efi_item_ops;
        efip->efi_item.li_mountp = mp;
        efip->efi_format.efi_nextents = nextents;
        efip->efi_format.efi_id = (__psint_t)(void*)efip;

        return (efip);
}

/*
 * This is called by the efd item code below to release references to
 * the given efi item.  Each efd calls this with the number of
 * extents that it has logged, and when the sum of these reaches
 * the total number of extents logged by this efi item we can free
 * the efi item.
 *
 * Freeing the efi item requires that we remove it from the AIL.
 * We'll use the AIL lock to protect our counters as well as
 * the removal from the AIL.
 */
void
xfs_efi_release(xfs_efi_log_item_t      *efip,
                uint                    nextents)
{
        xfs_mount_t     *mp;
        int             extents_left;
        SPLDECL(s);

        mp = efip->efi_item.li_mountp;
        ASSERT(efip->efi_next_extent > 0);
        ASSERT(efip->efi_flags & XFS_EFI_COMMITTED);

        AIL_LOCK(mp, s);
        ASSERT(efip->efi_next_extent >= nextents);
        efip->efi_next_extent -= nextents;
        extents_left = efip->efi_next_extent;
        if (extents_left == 0) {
                /*
                 * xfs_trans_delete_ail() drops the AIL lock.
                 */
                xfs_trans_delete_ail(mp, (xfs_log_item_t *)efip, s);
                xfs_efi_item_free(efip);
        } else {
                AIL_UNLOCK(mp, s);
        }
}

/*
 * This is called when the transaction that should be committing the
 * EFD corresponding to the given EFI is aborted.  The committed and
 * canceled flags are used to coordinate the freeing of the EFI and
 * the references by the transaction that committed it.
 */
STATIC void
xfs_efi_cancel(
        xfs_efi_log_item_t      *efip)
{
        xfs_mount_t     *mp;
        SPLDECL(s);

        mp = efip->efi_item.li_mountp;
        AIL_LOCK(mp, s);
        if (efip->efi_flags & XFS_EFI_COMMITTED) {
                /*
                 * xfs_trans_delete_ail() drops the AIL lock.
                 */
                xfs_trans_delete_ail(mp, (xfs_log_item_t *)efip, s);
                xfs_efi_item_free(efip);
        } else {
                efip->efi_flags |= XFS_EFI_CANCELED;
                AIL_UNLOCK(mp, s);
        }
}

STATIC void
xfs_efd_item_free(xfs_efd_log_item_t *efdp)
{
        int nexts = efdp->efd_format.efd_nextents;

        if (nexts > XFS_EFD_MAX_FAST_EXTENTS) {
                kmem_free(efdp, sizeof(xfs_efd_log_item_t) +
                                (nexts - 1) * sizeof(xfs_extent_t));
        } else {
                kmem_zone_free(xfs_efd_zone, efdp);
        }
}

/*
 * This returns the number of iovecs needed to log the given efd item.
 * We only need 1 iovec for an efd item.  It just logs the efd_log_format
 * structure.
 */
/*ARGSUSED*/
STATIC uint
xfs_efd_item_size(xfs_efd_log_item_t *efdp)
{
        return 1;
}

/*
 * This is called to fill in the vector of log iovecs for the
 * given efd log item. We use only 1 iovec, and we point that
 * at the efd_log_format structure embedded in the efd item.
 * It is at this point that we assert that all of the extent
 * slots in the efd item have been filled.
 */
STATIC void
xfs_efd_item_format(xfs_efd_log_item_t  *efdp,
                    xfs_log_iovec_t     *log_vector)
{
        uint    size;

        ASSERT(efdp->efd_next_extent == efdp->efd_format.efd_nextents);

        efdp->efd_format.efd_type = XFS_LI_EFD;

        size = sizeof(xfs_efd_log_format_t);
        size += (efdp->efd_format.efd_nextents - 1) * sizeof(xfs_extent_t);
        efdp->efd_format.efd_size = 1;

        log_vector->i_addr = (xfs_caddr_t)&(efdp->efd_format);
        log_vector->i_len = size;
        ASSERT(size >= sizeof(xfs_efd_log_format_t));
}


/*
 * Pinning has no meaning for an efd item, so just return.
 */
/*ARGSUSED*/
STATIC void
xfs_efd_item_pin(xfs_efd_log_item_t *efdp)
{
        return;
}


/*
 * Since pinning has no meaning for an efd item, unpinning does
 * not either.
 */
/*ARGSUSED*/
STATIC void
xfs_efd_item_unpin(xfs_efd_log_item_t *efdp, int stale)
{
        return;
}

/*ARGSUSED*/
STATIC void
xfs_efd_item_unpin_remove(xfs_efd_log_item_t *efdp, xfs_trans_t *tp)
{
        return;
}

/*
 * Efd items have no locking, so just return success.
 */
/*ARGSUSED*/
STATIC uint
xfs_efd_item_trylock(xfs_efd_log_item_t *efdp)
{
        return XFS_ITEM_LOCKED;
}

/*
 * Efd items have no locking or pushing, so return failure
 * so that the caller doesn't bother with us.
 */
/*ARGSUSED*/
STATIC void
xfs_efd_item_unlock(xfs_efd_log_item_t *efdp)
{
        if (efdp->efd_item.li_flags & XFS_LI_ABORTED)
                xfs_efd_item_abort(efdp);
        return;
}

/*
 * When the efd item is committed to disk, all we need to do
 * is delete our reference to our partner efi item and then
 * free ourselves.  Since we're freeing ourselves we must
 * return -1 to keep the transaction code from further referencing
 * this item.
 */
/*ARGSUSED*/
STATIC xfs_lsn_t
xfs_efd_item_committed(xfs_efd_log_item_t *efdp, xfs_lsn_t lsn)
{
        /*
         * If we got a log I/O error, it's always the case that the LR with the
         * EFI got unpinned and freed before the EFD got aborted.
         */
        if ((efdp->efd_item.li_flags & XFS_LI_ABORTED) == 0)
                xfs_efi_release(efdp->efd_efip, efdp->efd_format.efd_nextents);

        xfs_efd_item_free(efdp);
        return (xfs_lsn_t)-1;
}

/*
 * The transaction of which this EFD is a part has been aborted.
 * Inform its companion EFI of this fact and then clean up after
 * ourselves.  No need to clean up the slot for the item in the
 * transaction.  That was done by the unpin code which is called
 * prior to this routine in the abort/fs-shutdown path.
 */
STATIC void
xfs_efd_item_abort(xfs_efd_log_item_t *efdp)
{
        /*
         * If we got a log I/O error, it's always the case that the LR with the
         * EFI got unpinned and freed before the EFD got aborted. So don't
         * reference the EFI at all in that case.
         */
        if ((efdp->efd_item.li_flags & XFS_LI_ABORTED) == 0)
                xfs_efi_cancel(efdp->efd_efip);

        xfs_efd_item_free(efdp);
}

/*
 * There isn't much you can do to push on an efd item.  It is simply
 * stuck waiting for the log to be flushed to disk.
 */
/*ARGSUSED*/
STATIC void
xfs_efd_item_push(xfs_efd_log_item_t *efdp)
{
        return;
}

/*
 * The EFD 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.
 */
/*ARGSUSED*/
STATIC void
xfs_efd_item_committing(xfs_efd_log_item_t *efip, xfs_lsn_t lsn)
{
        return;
}

/*
 * This is the ops vector shared by all efd log items.
 */
STATIC struct xfs_item_ops xfs_efd_item_ops = {
        .iop_size       = (uint(*)(xfs_log_item_t*))xfs_efd_item_size,
        .iop_format     = (void(*)(xfs_log_item_t*, xfs_log_iovec_t*))
                                        xfs_efd_item_format,
        .iop_pin        = (void(*)(xfs_log_item_t*))xfs_efd_item_pin,
        .iop_unpin      = (void(*)(xfs_log_item_t*, int))xfs_efd_item_unpin,
        .iop_unpin_remove = (void(*)(xfs_log_item_t*, xfs_trans_t*))
                                        xfs_efd_item_unpin_remove,
        .iop_trylock    = (uint(*)(xfs_log_item_t*))xfs_efd_item_trylock,
        .iop_unlock     = (void(*)(xfs_log_item_t*))xfs_efd_item_unlock,
        .iop_committed  = (xfs_lsn_t(*)(xfs_log_item_t*, xfs_lsn_t))
                                        xfs_efd_item_committed,
        .iop_push       = (void(*)(xfs_log_item_t*))xfs_efd_item_push,
        .iop_abort      = (void(*)(xfs_log_item_t*))xfs_efd_item_abort,
        .iop_pushbuf    = NULL,
        .iop_committing = (void(*)(xfs_log_item_t*, xfs_lsn_t))
                                        xfs_efd_item_committing
};


/*
 * Allocate and initialize an efd item with the given number of extents.
 */
xfs_efd_log_item_t *
xfs_efd_init(xfs_mount_t        *mp,
             xfs_efi_log_item_t *efip,
             uint               nextents)

{
        xfs_efd_log_item_t      *efdp;
        uint                    size;

        ASSERT(nextents > 0);
        if (nextents > XFS_EFD_MAX_FAST_EXTENTS) {
                size = (uint)(sizeof(xfs_efd_log_item_t) +
                        ((nextents - 1) * sizeof(xfs_extent_t)));
                efdp = (xfs_efd_log_item_t*)kmem_zalloc(size, KM_SLEEP);
        } else {
                efdp = (xfs_efd_log_item_t*)kmem_zone_zalloc(xfs_efd_zone,
                                                             KM_SLEEP);
        }

        efdp->efd_item.li_type = XFS_LI_EFD;
        efdp->efd_item.li_ops = &xfs_efd_item_ops;
        efdp->efd_item.li_mountp = mp;
        efdp->efd_efip = efip;
        efdp->efd_format.efd_nextents = nextents;
        efdp->efd_format.efd_efi_id = efip->efi_format.efi_id;

        return (efdp);
}