patch-2.4.25 linux-2.4.25/fs/xfs/xfs_trans.c

Next file: linux-2.4.25/fs/xfs/xfs_trans.h
Previous file: linux-2.4.25/fs/xfs/xfs_sb.h
Back to the patch index
Back to the overall index

diff -urN linux-2.4.24/fs/xfs/xfs_trans.c linux-2.4.25/fs/xfs/xfs_trans.c
@@ -0,0 +1,1298 @@
+/*
+ * 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 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/
+ */
+
+#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_sb.h"
+#include "xfs_ag.h"
+#include "xfs_dir.h"
+#include "xfs_dir2.h"
+#include "xfs_dmapi.h"
+#include "xfs_mount.h"
+#include "xfs_error.h"
+#include "xfs_trans_priv.h"
+#include "xfs_alloc_btree.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_ialloc_btree.h"
+#include "xfs_btree.h"
+#include "xfs_ialloc.h"
+#include "xfs_alloc.h"
+#include "xfs_attr_sf.h"
+#include "xfs_dir_sf.h"
+#include "xfs_dir2_sf.h"
+#include "xfs_dinode.h"
+#include "xfs_inode.h"
+#include "xfs_bmap.h"
+#include "xfs_da_btree.h"
+#include "xfs_quota.h"
+#include "xfs_trans_space.h"
+
+
+STATIC void	xfs_trans_apply_sb_deltas(xfs_trans_t *);
+STATIC uint	xfs_trans_count_vecs(xfs_trans_t *);
+STATIC void	xfs_trans_fill_vecs(xfs_trans_t *, xfs_log_iovec_t *);
+STATIC void	xfs_trans_uncommit(xfs_trans_t *, uint);
+STATIC void	xfs_trans_committed(xfs_trans_t *, int);
+STATIC void	xfs_trans_chunk_committed(xfs_log_item_chunk_t *, xfs_lsn_t, int);
+STATIC void	xfs_trans_free(xfs_trans_t *);
+
+kmem_zone_t		*xfs_trans_zone;
+
+
+/*
+ * Initialize the precomputed transaction reservation values
+ * in the mount structure.
+ */
+void
+xfs_trans_init(
+	xfs_mount_t	*mp)
+{
+	xfs_trans_reservations_t	*resp;
+
+	resp = &(mp->m_reservations);
+	resp->tr_write =
+		(uint)(XFS_CALC_WRITE_LOG_RES(mp) + XFS_DQUOT_LOGRES(mp));
+	resp->tr_itruncate =
+		(uint)(XFS_CALC_ITRUNCATE_LOG_RES(mp) + XFS_DQUOT_LOGRES(mp));
+	resp->tr_rename =
+		(uint)(XFS_CALC_RENAME_LOG_RES(mp) + XFS_DQUOT_LOGRES(mp));
+	resp->tr_link = (uint)XFS_CALC_LINK_LOG_RES(mp);
+	resp->tr_remove =
+		(uint)(XFS_CALC_REMOVE_LOG_RES(mp) + XFS_DQUOT_LOGRES(mp));
+	resp->tr_symlink =
+		(uint)(XFS_CALC_SYMLINK_LOG_RES(mp) + XFS_DQUOT_LOGRES(mp));
+	resp->tr_create =
+		(uint)(XFS_CALC_CREATE_LOG_RES(mp) + XFS_DQUOT_LOGRES(mp));
+	resp->tr_mkdir =
+		(uint)(XFS_CALC_MKDIR_LOG_RES(mp) + XFS_DQUOT_LOGRES(mp));
+	resp->tr_ifree =
+		(uint)(XFS_CALC_IFREE_LOG_RES(mp) + XFS_DQUOT_LOGRES(mp));
+	resp->tr_ichange =
+		(uint)(XFS_CALC_ICHANGE_LOG_RES(mp) + XFS_DQUOT_LOGRES(mp));
+	resp->tr_growdata = (uint)XFS_CALC_GROWDATA_LOG_RES(mp);
+	resp->tr_swrite = (uint)XFS_CALC_SWRITE_LOG_RES(mp);
+	resp->tr_writeid = (uint)XFS_CALC_WRITEID_LOG_RES(mp);
+	resp->tr_addafork =
+		(uint)(XFS_CALC_ADDAFORK_LOG_RES(mp) + XFS_DQUOT_LOGRES(mp));
+	resp->tr_attrinval = (uint)XFS_CALC_ATTRINVAL_LOG_RES(mp);
+	resp->tr_attrset =
+		(uint)(XFS_CALC_ATTRSET_LOG_RES(mp) + XFS_DQUOT_LOGRES(mp));
+	resp->tr_attrrm =
+		(uint)(XFS_CALC_ATTRRM_LOG_RES(mp) + XFS_DQUOT_LOGRES(mp));
+	resp->tr_clearagi = (uint)XFS_CALC_CLEAR_AGI_BUCKET_LOG_RES(mp);
+	resp->tr_growrtalloc = (uint)XFS_CALC_GROWRTALLOC_LOG_RES(mp);
+	resp->tr_growrtzero = (uint)XFS_CALC_GROWRTZERO_LOG_RES(mp);
+	resp->tr_growrtfree = (uint)XFS_CALC_GROWRTFREE_LOG_RES(mp);
+}
+
+/*
+ * This routine is called to allocate a transaction structure.
+ * The type parameter indicates the type of the transaction.  These
+ * are enumerated in xfs_trans.h.
+ *
+ * Dynamically allocate the transaction structure from the transaction
+ * zone, initialize it, and return it to the caller.
+ */
+xfs_trans_t *
+xfs_trans_alloc(
+	xfs_mount_t	*mp,
+	uint		type)
+{
+	xfs_check_frozen(mp, NULL, XFS_FREEZE_TRANS);
+	return (_xfs_trans_alloc(mp, type));
+
+}
+
+xfs_trans_t *
+_xfs_trans_alloc(
+	xfs_mount_t	*mp,
+	uint		type)
+{
+	xfs_trans_t	*tp;
+
+	ASSERT(xfs_trans_zone != NULL);
+	tp = kmem_zone_zalloc(xfs_trans_zone, KM_SLEEP);
+
+	/*
+	 * Initialize the transaction structure.
+	 */
+	tp->t_magic = XFS_TRANS_MAGIC;
+	tp->t_type = type;
+	tp->t_mountp = mp;
+	tp->t_items_free = XFS_LIC_NUM_SLOTS;
+	tp->t_busy_free = XFS_LBC_NUM_SLOTS;
+	XFS_LIC_INIT(&(tp->t_items));
+	XFS_LBC_INIT(&(tp->t_busy));
+
+	return (tp);
+}
+
+/*
+ * This is called to create a new transaction which will share the
+ * permanent log reservation of the given transaction.  The remaining
+ * unused block and rt extent reservations are also inherited.  This
+ * implies that the original transaction is no longer allowed to allocate
+ * blocks.  Locks and log items, however, are no inherited.  They must
+ * be added to the new transaction explicitly.
+ */
+xfs_trans_t *
+xfs_trans_dup(
+	xfs_trans_t	*tp)
+{
+	xfs_trans_t	*ntp;
+
+	ntp = kmem_zone_zalloc(xfs_trans_zone, KM_SLEEP);
+
+	/*
+	 * Initialize the new transaction structure.
+	 */
+	ntp->t_magic = XFS_TRANS_MAGIC;
+	ntp->t_type = tp->t_type;
+	ntp->t_mountp = tp->t_mountp;
+	ntp->t_items_free = XFS_LIC_NUM_SLOTS;
+	ntp->t_busy_free = XFS_LBC_NUM_SLOTS;
+	XFS_LIC_INIT(&(ntp->t_items));
+	XFS_LBC_INIT(&(ntp->t_busy));
+
+	ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
+
+#if defined(XLOG_NOLOG) || defined(DEBUG)
+	ASSERT(!xlog_debug || tp->t_ticket != NULL);
+#else
+	ASSERT(tp->t_ticket != NULL);
+#endif
+	ntp->t_flags = XFS_TRANS_PERM_LOG_RES | (tp->t_flags & XFS_TRANS_RESERVE);
+	ntp->t_ticket = tp->t_ticket;
+	ntp->t_blk_res = tp->t_blk_res - tp->t_blk_res_used;
+	tp->t_blk_res = tp->t_blk_res_used;
+	ntp->t_rtx_res = tp->t_rtx_res - tp->t_rtx_res_used;
+	tp->t_rtx_res = tp->t_rtx_res_used;
+	PFLAGS_DUP(&tp->t_pflags, &ntp->t_pflags);
+
+	XFS_TRANS_DUP_DQINFO(tp->t_mountp, tp, ntp);
+
+	atomic_inc(&tp->t_mountp->m_active_trans);
+	return ntp;
+}
+
+/*
+ * This is called to reserve free disk blocks and log space for the
+ * given transaction.  This must be done before allocating any resources
+ * within the transaction.
+ *
+ * This will return ENOSPC if there are not enough blocks available.
+ * It will sleep waiting for available log space.
+ * The only valid value for the flags parameter is XFS_RES_LOG_PERM, which
+ * is used by long running transactions.  If any one of the reservations
+ * fails then they will all be backed out.
+ *
+ * This does not do quota reservations. That typically is done by the
+ * caller afterwards.
+ */
+int
+xfs_trans_reserve(
+	xfs_trans_t	*tp,
+	uint		blocks,
+	uint		logspace,
+	uint		rtextents,
+	uint		flags,
+	uint		logcount)
+{
+	int		log_flags;
+	int		error;
+	int	rsvd;
+
+	error = 0;
+	rsvd = (tp->t_flags & XFS_TRANS_RESERVE) != 0;
+
+	/* Mark this thread as being in a transaction */
+        PFLAGS_SET_FSTRANS(&tp->t_pflags);
+
+	/*
+	 * Attempt to reserve the needed disk blocks by decrementing
+	 * the number needed from the number available.  This will
+	 * fail if the count would go below zero.
+	 */
+	if (blocks > 0) {
+		error = xfs_mod_incore_sb(tp->t_mountp, XFS_SBS_FDBLOCKS,
+					  -blocks, rsvd);
+		if (error != 0) {
+                        PFLAGS_RESTORE(&tp->t_pflags);
+			return (XFS_ERROR(ENOSPC));
+		}
+		tp->t_blk_res += blocks;
+	}
+
+	/*
+	 * Reserve the log space needed for this transaction.
+	 */
+	if (logspace > 0) {
+		ASSERT((tp->t_log_res == 0) || (tp->t_log_res == logspace));
+		ASSERT((tp->t_log_count == 0) ||
+			(tp->t_log_count == logcount));
+		if (flags & XFS_TRANS_PERM_LOG_RES) {
+			log_flags = XFS_LOG_PERM_RESERV;
+			tp->t_flags |= XFS_TRANS_PERM_LOG_RES;
+		} else {
+			ASSERT(tp->t_ticket == NULL);
+			ASSERT(!(tp->t_flags & XFS_TRANS_PERM_LOG_RES));
+			log_flags = 0;
+		}
+
+		error = xfs_log_reserve(tp->t_mountp, logspace, logcount,
+					&tp->t_ticket,
+					XFS_TRANSACTION, log_flags);
+		if (error) {
+			goto undo_blocks;
+		}
+		tp->t_log_res = logspace;
+		tp->t_log_count = logcount;
+	}
+
+	/*
+	 * Attempt to reserve the needed realtime extents by decrementing
+	 * the number needed from the number available.  This will
+	 * fail if the count would go below zero.
+	 */
+	if (rtextents > 0) {
+		error = xfs_mod_incore_sb(tp->t_mountp, XFS_SBS_FREXTENTS,
+					  -rtextents, rsvd);
+		if (error) {
+			error = XFS_ERROR(ENOSPC);
+			goto undo_log;
+		}
+		tp->t_rtx_res += rtextents;
+	}
+
+	return 0;
+
+	/*
+	 * Error cases jump to one of these labels to undo any
+	 * reservations which have already been performed.
+	 */
+undo_log:
+	if (logspace > 0) {
+		if (flags & XFS_TRANS_PERM_LOG_RES) {
+			log_flags = XFS_LOG_REL_PERM_RESERV;
+		} else {
+			log_flags = 0;
+		}
+		xfs_log_done(tp->t_mountp, tp->t_ticket, NULL, log_flags);
+		tp->t_ticket = NULL;
+		tp->t_log_res = 0;
+		tp->t_flags &= ~XFS_TRANS_PERM_LOG_RES;
+	}
+
+undo_blocks:
+	if (blocks > 0) {
+		(void) xfs_mod_incore_sb(tp->t_mountp, XFS_SBS_FDBLOCKS,
+					 blocks, rsvd);
+		tp->t_blk_res = 0;
+	}
+
+        PFLAGS_RESTORE(&tp->t_pflags);
+
+	return (error);
+}
+
+
+/*
+ * This is called to set the a callback to be called when the given
+ * transaction is committed to disk.  The transaction pointer and the
+ * argument pointer will be passed to the callback routine.
+ *
+ * Only one callback can be associated with any single transaction.
+ */
+void
+xfs_trans_callback(
+	xfs_trans_t		*tp,
+	xfs_trans_callback_t	callback,
+	void			*arg)
+{
+	ASSERT(tp->t_callback == NULL);
+	tp->t_callback = callback;
+	tp->t_callarg = arg;
+}
+
+
+/*
+ * Record the indicated change to the given field for application
+ * to the file system's superblock when the transaction commits.
+ * For now, just store the change in the transaction structure.
+ *
+ * Mark the transaction structure to indicate that the superblock
+ * needs to be updated before committing.
+ */
+void
+xfs_trans_mod_sb(
+	xfs_trans_t	*tp,
+	uint		field,
+	long		delta)
+{
+
+	switch (field) {
+	case XFS_TRANS_SB_ICOUNT:
+		tp->t_icount_delta += delta;
+		break;
+	case XFS_TRANS_SB_IFREE:
+		tp->t_ifree_delta += delta;
+		break;
+	case XFS_TRANS_SB_FDBLOCKS:
+		/*
+		 * Track the number of blocks allocated in the
+		 * transaction.  Make sure it does not exceed the
+		 * number reserved.
+		 */
+		if (delta < 0) {
+			tp->t_blk_res_used += (uint)-delta;
+			ASSERT(tp->t_blk_res_used <= tp->t_blk_res);
+		}
+		tp->t_fdblocks_delta += delta;
+		break;
+	case XFS_TRANS_SB_RES_FDBLOCKS:
+		/*
+		 * The allocation has already been applied to the
+		 * in-core superblock's counter.  This should only
+		 * be applied to the on-disk superblock.
+		 */
+		ASSERT(delta < 0);
+		tp->t_res_fdblocks_delta += delta;
+		break;
+	case XFS_TRANS_SB_FREXTENTS:
+		/*
+		 * Track the number of blocks allocated in the
+		 * transaction.  Make sure it does not exceed the
+		 * number reserved.
+		 */
+		if (delta < 0) {
+			tp->t_rtx_res_used += (uint)-delta;
+			ASSERT(tp->t_rtx_res_used <= tp->t_rtx_res);
+		}
+		tp->t_frextents_delta += delta;
+		break;
+	case XFS_TRANS_SB_RES_FREXTENTS:
+		/*
+		 * The allocation has already been applied to the
+		 * in-core superblocks's counter.  This should only
+		 * be applied to the on-disk superblock.
+		 */
+		ASSERT(delta < 0);
+		tp->t_res_frextents_delta += delta;
+		break;
+	case XFS_TRANS_SB_DBLOCKS:
+		ASSERT(delta > 0);
+		tp->t_dblocks_delta += delta;
+		break;
+	case XFS_TRANS_SB_AGCOUNT:
+		ASSERT(delta > 0);
+		tp->t_agcount_delta += delta;
+		break;
+	case XFS_TRANS_SB_IMAXPCT:
+		tp->t_imaxpct_delta += delta;
+		break;
+	case XFS_TRANS_SB_REXTSIZE:
+		tp->t_rextsize_delta += delta;
+		break;
+	case XFS_TRANS_SB_RBMBLOCKS:
+		tp->t_rbmblocks_delta += delta;
+		break;
+	case XFS_TRANS_SB_RBLOCKS:
+		tp->t_rblocks_delta += delta;
+		break;
+	case XFS_TRANS_SB_REXTENTS:
+		tp->t_rextents_delta += delta;
+		break;
+	case XFS_TRANS_SB_REXTSLOG:
+		tp->t_rextslog_delta += delta;
+		break;
+	default:
+		ASSERT(0);
+		return;
+	}
+
+	tp->t_flags |= (XFS_TRANS_SB_DIRTY | XFS_TRANS_DIRTY);
+}
+
+/*
+ * xfs_trans_apply_sb_deltas() is called from the commit code
+ * to bring the superblock buffer into the current transaction
+ * and modify it as requested by earlier calls to xfs_trans_mod_sb().
+ *
+ * For now we just look at each field allowed to change and change
+ * it if necessary.
+ */
+STATIC void
+xfs_trans_apply_sb_deltas(
+	xfs_trans_t	*tp)
+{
+	xfs_sb_t	*sbp;
+	xfs_buf_t	*bp;
+	int		whole = 0;
+
+	bp = xfs_trans_getsb(tp, tp->t_mountp, 0);
+	sbp = XFS_BUF_TO_SBP(bp);
+
+	/*
+	 * Check that superblock mods match the mods made to AGF counters.
+	 */
+	ASSERT((tp->t_fdblocks_delta + tp->t_res_fdblocks_delta) ==
+	       (tp->t_ag_freeblks_delta + tp->t_ag_flist_delta +
+		tp->t_ag_btree_delta));
+
+	if (tp->t_icount_delta != 0) {
+		INT_MOD(sbp->sb_icount, ARCH_CONVERT, tp->t_icount_delta);
+	}
+	if (tp->t_ifree_delta != 0) {
+		INT_MOD(sbp->sb_ifree, ARCH_CONVERT, tp->t_ifree_delta);
+	}
+
+	if (tp->t_fdblocks_delta != 0) {
+		INT_MOD(sbp->sb_fdblocks, ARCH_CONVERT, tp->t_fdblocks_delta);
+	}
+	if (tp->t_res_fdblocks_delta != 0) {
+		INT_MOD(sbp->sb_fdblocks, ARCH_CONVERT, tp->t_res_fdblocks_delta);
+	}
+
+	if (tp->t_frextents_delta != 0) {
+		INT_MOD(sbp->sb_frextents, ARCH_CONVERT, tp->t_frextents_delta);
+	}
+	if (tp->t_dblocks_delta != 0) {
+		INT_MOD(sbp->sb_dblocks, ARCH_CONVERT, tp->t_dblocks_delta);
+		whole = 1;
+	}
+	if (tp->t_agcount_delta != 0) {
+		INT_MOD(sbp->sb_agcount, ARCH_CONVERT, tp->t_agcount_delta);
+		whole = 1;
+	}
+	if (tp->t_imaxpct_delta != 0) {
+		INT_MOD(sbp->sb_imax_pct, ARCH_CONVERT, tp->t_imaxpct_delta);
+		whole = 1;
+	}
+	if (tp->t_rextsize_delta != 0) {
+		INT_MOD(sbp->sb_rextsize, ARCH_CONVERT, tp->t_rextsize_delta);
+		whole = 1;
+	}
+	if (tp->t_rbmblocks_delta != 0) {
+		INT_MOD(sbp->sb_rbmblocks, ARCH_CONVERT, tp->t_rbmblocks_delta);
+		whole = 1;
+	}
+	if (tp->t_rblocks_delta != 0) {
+		INT_MOD(sbp->sb_rblocks, ARCH_CONVERT, tp->t_rblocks_delta);
+		whole = 1;
+	}
+	if (tp->t_rextents_delta != 0) {
+		INT_MOD(sbp->sb_rextents, ARCH_CONVERT, tp->t_rextents_delta);
+		whole = 1;
+	}
+	if (tp->t_rextslog_delta != 0) {
+		INT_MOD(sbp->sb_rextslog, ARCH_CONVERT, tp->t_rextslog_delta);
+		whole = 1;
+	}
+
+	if (whole)
+		/*
+		 * Log the whole thing, the fields are discontiguous.
+		 */
+		xfs_trans_log_buf(tp, bp, 0, sizeof(xfs_sb_t) - 1);
+	else
+		/*
+		 * Since all the modifiable fields are contiguous, we
+		 * can get away with this.
+		 */
+		xfs_trans_log_buf(tp, bp, offsetof(xfs_sb_t, sb_icount),
+				  offsetof(xfs_sb_t, sb_frextents) +
+				  sizeof(sbp->sb_frextents) - 1);
+
+	XFS_MTOVFS(tp->t_mountp)->vfs_super->s_dirt = 1;
+}
+
+/*
+ * xfs_trans_unreserve_and_mod_sb() is called to release unused
+ * reservations and apply superblock counter changes to the in-core
+ * superblock.
+ *
+ * This is done efficiently with a single call to xfs_mod_incore_sb_batch().
+ */
+void
+xfs_trans_unreserve_and_mod_sb(
+	xfs_trans_t	*tp)
+{
+	xfs_mod_sb_t	msb[14];	/* If you add cases, add entries */
+	xfs_mod_sb_t	*msbp;
+	/* REFERENCED */
+	int		error;
+	int		rsvd;
+
+	msbp = msb;
+	rsvd = (tp->t_flags & XFS_TRANS_RESERVE) != 0;
+
+	/*
+	 * Release any reserved blocks.  Any that were allocated
+	 * will be taken back again by fdblocks_delta below.
+	 */
+	if (tp->t_blk_res > 0) {
+		msbp->msb_field = XFS_SBS_FDBLOCKS;
+		msbp->msb_delta = tp->t_blk_res;
+		msbp++;
+	}
+
+	/*
+	 * Release any reserved real time extents .  Any that were
+	 * allocated will be taken back again by frextents_delta below.
+	 */
+	if (tp->t_rtx_res > 0) {
+		msbp->msb_field = XFS_SBS_FREXTENTS;
+		msbp->msb_delta = tp->t_rtx_res;
+		msbp++;
+	}
+
+	/*
+	 * Apply any superblock modifications to the in-core version.
+	 * The t_res_fdblocks_delta and t_res_frextents_delta fields are
+	 * explicity NOT applied to the in-core superblock.
+	 * The idea is that that has already been done.
+	 */
+	if (tp->t_flags & XFS_TRANS_SB_DIRTY) {
+		if (tp->t_icount_delta != 0) {
+			msbp->msb_field = XFS_SBS_ICOUNT;
+			msbp->msb_delta = (int)tp->t_icount_delta;
+			msbp++;
+		}
+		if (tp->t_ifree_delta != 0) {
+			msbp->msb_field = XFS_SBS_IFREE;
+			msbp->msb_delta = (int)tp->t_ifree_delta;
+			msbp++;
+		}
+		if (tp->t_fdblocks_delta != 0) {
+			msbp->msb_field = XFS_SBS_FDBLOCKS;
+			msbp->msb_delta = (int)tp->t_fdblocks_delta;
+			msbp++;
+		}
+		if (tp->t_frextents_delta != 0) {
+			msbp->msb_field = XFS_SBS_FREXTENTS;
+			msbp->msb_delta = (int)tp->t_frextents_delta;
+			msbp++;
+		}
+		if (tp->t_dblocks_delta != 0) {
+			msbp->msb_field = XFS_SBS_DBLOCKS;
+			msbp->msb_delta = (int)tp->t_dblocks_delta;
+			msbp++;
+		}
+		if (tp->t_agcount_delta != 0) {
+			msbp->msb_field = XFS_SBS_AGCOUNT;
+			msbp->msb_delta = (int)tp->t_agcount_delta;
+			msbp++;
+		}
+		if (tp->t_imaxpct_delta != 0) {
+			msbp->msb_field = XFS_SBS_IMAX_PCT;
+			msbp->msb_delta = (int)tp->t_imaxpct_delta;
+			msbp++;
+		}
+		if (tp->t_rextsize_delta != 0) {
+			msbp->msb_field = XFS_SBS_REXTSIZE;
+			msbp->msb_delta = (int)tp->t_rextsize_delta;
+			msbp++;
+		}
+		if (tp->t_rbmblocks_delta != 0) {
+			msbp->msb_field = XFS_SBS_RBMBLOCKS;
+			msbp->msb_delta = (int)tp->t_rbmblocks_delta;
+			msbp++;
+		}
+		if (tp->t_rblocks_delta != 0) {
+			msbp->msb_field = XFS_SBS_RBLOCKS;
+			msbp->msb_delta = (int)tp->t_rblocks_delta;
+			msbp++;
+		}
+		if (tp->t_rextents_delta != 0) {
+			msbp->msb_field = XFS_SBS_REXTENTS;
+			msbp->msb_delta = (int)tp->t_rextents_delta;
+			msbp++;
+		}
+		if (tp->t_rextslog_delta != 0) {
+			msbp->msb_field = XFS_SBS_REXTSLOG;
+			msbp->msb_delta = (int)tp->t_rextslog_delta;
+			msbp++;
+		}
+	}
+
+	/*
+	 * If we need to change anything, do it.
+	 */
+	if (msbp > msb) {
+		error = xfs_mod_incore_sb_batch(tp->t_mountp, msb,
+			(uint)(msbp - msb), rsvd);
+		ASSERT(error == 0);
+	}
+}
+
+
+/*
+ * xfs_trans_commit
+ *
+ * Commit the given transaction to the log a/synchronously.
+ *
+ * XFS disk error handling mechanism is not based on a typical
+ * transaction abort mechanism. Logically after the filesystem
+ * gets marked 'SHUTDOWN', we can't let any new transactions
+ * be durable - ie. committed to disk - because some metadata might
+ * be inconsistent. In such cases, this returns an error, and the
+ * caller may assume that all locked objects joined to the transaction
+ * have already been unlocked as if the commit had succeeded.
+ * Do not reference the transaction structure after this call.
+ */
+ /*ARGSUSED*/
+int
+xfs_trans_commit(
+	xfs_trans_t	*tp,
+	uint		flags,
+	xfs_lsn_t	*commit_lsn_p)
+{
+	xfs_log_iovec_t		*log_vector;
+	int			nvec;
+	xfs_mount_t		*mp;
+	xfs_lsn_t		commit_lsn;
+	/* REFERENCED */
+	int			error;
+	int			log_flags;
+	int			sync;
+#define	XFS_TRANS_LOGVEC_COUNT	16
+	xfs_log_iovec_t		log_vector_fast[XFS_TRANS_LOGVEC_COUNT];
+#if defined(XLOG_NOLOG) || defined(DEBUG)
+	static xfs_lsn_t	trans_lsn = 1;
+#endif
+	void			*commit_iclog;
+	int			shutdown;
+
+	commit_lsn = -1;
+
+	/*
+	 * Determine whether this commit is releasing a permanent
+	 * log reservation or not.
+	 */
+	if (flags & XFS_TRANS_RELEASE_LOG_RES) {
+		ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
+		log_flags = XFS_LOG_REL_PERM_RESERV;
+	} else {
+		log_flags = 0;
+	}
+	mp = tp->t_mountp;
+
+	/*
+	 * If there is nothing to be logged by the transaction,
+	 * then unlock all of the items associated with the
+	 * transaction and free the transaction structure.
+	 * Also make sure to return any reserved blocks to
+	 * the free pool.
+	 */
+shut_us_down:
+	shutdown = XFS_FORCED_SHUTDOWN(mp) ? EIO : 0;
+	if (!(tp->t_flags & XFS_TRANS_DIRTY) || shutdown) {
+		xfs_trans_unreserve_and_mod_sb(tp);
+		/*
+		 * It is indeed possible for the transaction to be
+		 * not dirty but the dqinfo portion to be. All that
+		 * means is that we have some (non-persistent) quota
+		 * reservations that need to be unreserved.
+		 */
+		XFS_TRANS_UNRESERVE_AND_MOD_DQUOTS(mp, tp);
+		if (tp->t_ticket) {
+			commit_lsn = xfs_log_done(mp, tp->t_ticket,
+							NULL, log_flags);
+			if (commit_lsn == -1 && !shutdown)
+				shutdown = XFS_ERROR(EIO);
+		}
+                PFLAGS_RESTORE(&tp->t_pflags);
+		xfs_trans_free_items(tp, shutdown? XFS_TRANS_ABORT : 0);
+		xfs_trans_free_busy(tp);
+		xfs_trans_free(tp);
+		XFS_STATS_INC(xs_trans_empty);
+		if (commit_lsn_p)
+			*commit_lsn_p = commit_lsn;
+		return (shutdown);
+	}
+#if defined(XLOG_NOLOG) || defined(DEBUG)
+	ASSERT(!xlog_debug || tp->t_ticket != NULL);
+#else
+	ASSERT(tp->t_ticket != NULL);
+#endif
+
+	/*
+	 * If we need to update the superblock, then do it now.
+	 */
+	if (tp->t_flags & XFS_TRANS_SB_DIRTY) {
+		xfs_trans_apply_sb_deltas(tp);
+	}
+	XFS_TRANS_APPLY_DQUOT_DELTAS(mp, tp);
+
+	/*
+	 * Ask each log item how many log_vector entries it will
+	 * need so we can figure out how many to allocate.
+	 * Try to avoid the kmem_alloc() call in the common case
+	 * by using a vector from the stack when it fits.
+	 */
+	nvec = xfs_trans_count_vecs(tp);
+
+	if (nvec == 0) {
+		xfs_force_shutdown(mp, XFS_LOG_IO_ERROR);
+		goto shut_us_down;
+	}
+
+
+	if (nvec <= XFS_TRANS_LOGVEC_COUNT) {
+		log_vector = log_vector_fast;
+	} else {
+		log_vector = (xfs_log_iovec_t *)kmem_alloc(nvec *
+						   sizeof(xfs_log_iovec_t),
+						   KM_SLEEP);
+	}
+
+	/*
+	 * Fill in the log_vector and pin the logged items, and
+	 * then write the transaction to the log.
+	 */
+	xfs_trans_fill_vecs(tp, log_vector);
+
+	/*
+	 * Ignore errors here. xfs_log_done would do the right thing.
+	 * We need to put the ticket, etc. away.
+	 */
+	error = xfs_log_write(mp, log_vector, nvec, tp->t_ticket,
+			     &(tp->t_lsn));
+
+#if defined(XLOG_NOLOG) || defined(DEBUG)
+	if (xlog_debug) {
+		commit_lsn = xfs_log_done(mp, tp->t_ticket,
+					  &commit_iclog, log_flags);
+	} else {
+		commit_lsn = 0;
+		tp->t_lsn = trans_lsn++;
+	}
+#else
+	/*
+	 * This is the regular case.  At this point (after the call finishes),
+	 * the transaction is committed incore and could go out to disk at
+	 * any time.  However, all the items associated with the transaction
+	 * are still locked and pinned in memory.
+	 */
+	commit_lsn = xfs_log_done(mp, tp->t_ticket, &commit_iclog, log_flags);
+#endif
+
+	tp->t_commit_lsn = commit_lsn;
+	if (nvec > XFS_TRANS_LOGVEC_COUNT) {
+		kmem_free(log_vector, nvec * sizeof(xfs_log_iovec_t));
+	}
+
+	if (commit_lsn_p)
+		*commit_lsn_p = commit_lsn;
+
+	/*
+	 * If we got a log write error. Unpin the logitems that we
+	 * had pinned, clean up, free trans structure, and return error.
+	 */
+	if (error || commit_lsn == -1) {
+                PFLAGS_RESTORE(&tp->t_pflags);
+		xfs_trans_uncommit(tp, flags|XFS_TRANS_ABORT);
+		return XFS_ERROR(EIO);
+	}
+
+	/*
+	 * Once the transaction has committed, unused
+	 * reservations need to be released and changes to
+	 * the superblock need to be reflected in the in-core
+	 * version.  Do that now.
+	 */
+	xfs_trans_unreserve_and_mod_sb(tp);
+
+	sync = tp->t_flags & XFS_TRANS_SYNC;
+
+	/*
+	 * Tell the LM to call the transaction completion routine
+	 * when the log write with LSN commit_lsn completes (e.g.
+	 * when the transaction commit really hits the on-disk log).
+	 * After this call we cannot reference tp, because the call
+	 * can happen at any time and the call will free the transaction
+	 * structure pointed to by tp.  The only case where we call
+	 * the completion routine (xfs_trans_committed) directly is
+	 * if the log is turned off on a debug kernel or we're
+	 * running in simulation mode (the log is explicitly turned
+	 * off).
+	 */
+	tp->t_logcb.cb_func = (void(*)(void*, int))xfs_trans_committed;
+	tp->t_logcb.cb_arg = tp;
+
+	/* We need to pass the iclog buffer which was used for the
+	 * transaction commit record into this function, and attach
+	 * the callback to it. The callback must be attached before
+	 * the items are unlocked to avoid racing with other threads
+	 * waiting for an item to unlock.
+	 */
+	error = xfs_log_notify(mp, commit_iclog, &(tp->t_logcb));
+
+	/* mark this thread as no longer being in a transaction */
+        PFLAGS_RESTORE(&tp->t_pflags);
+
+	/*
+	 * Once all the items of the transaction have been copied
+	 * to the in core log and the callback is attached, the
+	 * items can be unlocked.
+	 *
+	 * This will free descriptors pointing to items which were
+	 * not logged since there is nothing more to do with them.
+	 * For items which were logged, we will keep pointers to them
+	 * so they can be unpinned after the transaction commits to disk.
+	 * This will also stamp each modified meta-data item with
+	 * the commit lsn of this transaction for dependency tracking
+	 * purposes.
+	 */
+	xfs_trans_unlock_items(tp, commit_lsn);
+
+	/*
+	 * Now that the xfs_trans_committed callback has been attached,
+	 * and the items are released we can finally allow the iclog to
+	 * go to disk.
+	 */
+	error = xfs_log_release_iclog(mp, commit_iclog);
+
+	/*
+	 * If the transaction needs to be synchronous, then force the
+	 * log out now and wait for it.
+	 */
+	if (sync) {
+		if (!error)
+			error = xfs_log_force(mp, commit_lsn,
+				      XFS_LOG_FORCE | XFS_LOG_SYNC);
+		XFS_STATS_INC(xs_trans_sync);
+	} else {
+		XFS_STATS_INC(xs_trans_async);
+	}
+
+	return (error);
+}
+
+
+/*
+ * Total up the number of log iovecs needed to commit this
+ * transaction.  The transaction itself needs one for the
+ * transaction header.  Ask each dirty item in turn how many
+ * it needs to get the total.
+ */
+STATIC uint
+xfs_trans_count_vecs(
+	xfs_trans_t	*tp)
+{
+	int			nvecs;
+	xfs_log_item_desc_t	*lidp;
+
+	nvecs = 1;
+	lidp = xfs_trans_first_item(tp);
+	ASSERT(lidp != NULL);
+
+	/* In the non-debug case we need to start bailing out if we
+	 * didn't find a log_item here, return zero and let trans_commit
+	 * deal with it.
+	 */
+	if (lidp == NULL)
+		return 0;
+
+	while (lidp != NULL) {
+		/*
+		 * Skip items which aren't dirty in this transaction.
+		 */
+		if (!(lidp->lid_flags & XFS_LID_DIRTY)) {
+			lidp = xfs_trans_next_item(tp, lidp);
+			continue;
+		}
+		lidp->lid_size = IOP_SIZE(lidp->lid_item);
+		nvecs += lidp->lid_size;
+		lidp = xfs_trans_next_item(tp, lidp);
+	}
+
+	return nvecs;
+}
+
+/*
+ * Called from the trans_commit code when we notice that
+ * the filesystem is in the middle of a forced shutdown.
+ */
+STATIC void
+xfs_trans_uncommit(
+	xfs_trans_t	*tp,
+	uint		flags)
+{
+	xfs_log_item_desc_t	*lidp;
+
+	for (lidp = xfs_trans_first_item(tp);
+	     lidp != NULL;
+	     lidp = xfs_trans_next_item(tp, lidp)) {
+		/*
+		 * Unpin all but those that aren't dirty.
+		 */
+		if (lidp->lid_flags & XFS_LID_DIRTY)
+			IOP_UNPIN_REMOVE(lidp->lid_item, tp);
+	}
+
+	xfs_trans_unreserve_and_mod_sb(tp);
+	XFS_TRANS_UNRESERVE_AND_MOD_DQUOTS(tp->t_mountp, tp);
+
+	xfs_trans_free_items(tp, flags);
+	xfs_trans_free_busy(tp);
+	xfs_trans_free(tp);
+}
+
+/*
+ * Fill in the vector with pointers to data to be logged
+ * by this transaction.  The transaction header takes
+ * the first vector, and then each dirty item takes the
+ * number of vectors it indicated it needed in xfs_trans_count_vecs().
+ *
+ * As each item fills in the entries it needs, also pin the item
+ * so that it cannot be flushed out until the log write completes.
+ */
+STATIC void
+xfs_trans_fill_vecs(
+	xfs_trans_t		*tp,
+	xfs_log_iovec_t		*log_vector)
+{
+	xfs_log_item_desc_t	*lidp;
+	xfs_log_iovec_t		*vecp;
+	uint			nitems;
+
+	/*
+	 * Skip over the entry for the transaction header, we'll
+	 * fill that in at the end.
+	 */
+	vecp = log_vector + 1;		/* pointer arithmetic */
+
+	nitems = 0;
+	lidp = xfs_trans_first_item(tp);
+	ASSERT(lidp != NULL);
+	while (lidp != NULL) {
+		/*
+		 * Skip items which aren't dirty in this transaction.
+		 */
+		if (!(lidp->lid_flags & XFS_LID_DIRTY)) {
+			lidp = xfs_trans_next_item(tp, lidp);
+			continue;
+		}
+		/*
+		 * The item may be marked dirty but not log anything.
+		 * This can be used to get called when a transaction
+		 * is committed.
+		 */
+		if (lidp->lid_size) {
+			nitems++;
+		}
+		IOP_FORMAT(lidp->lid_item, vecp);
+		vecp += lidp->lid_size;		/* pointer arithmetic */
+		IOP_PIN(lidp->lid_item);
+		lidp = xfs_trans_next_item(tp, lidp);
+	}
+
+	/*
+	 * Now that we've counted the number of items in this
+	 * transaction, fill in the transaction header.
+	 */
+	tp->t_header.th_magic = XFS_TRANS_HEADER_MAGIC;
+	tp->t_header.th_type = tp->t_type;
+	tp->t_header.th_num_items = nitems;
+	log_vector->i_addr = (xfs_caddr_t)&tp->t_header;
+	log_vector->i_len = sizeof(xfs_trans_header_t);
+}
+
+
+/*
+ * Unlock all of the transaction's items and free the transaction.
+ * The transaction must not have modified any of its items, because
+ * there is no way to restore them to their previous state.
+ *
+ * If the transaction has made a log reservation, make sure to release
+ * it as well.
+ */
+void
+xfs_trans_cancel(
+	xfs_trans_t		*tp,
+	int			flags)
+{
+	int			log_flags;
+#ifdef DEBUG
+	xfs_log_item_chunk_t	*licp;
+	xfs_log_item_desc_t	*lidp;
+	xfs_log_item_t		*lip;
+	int			i;
+#endif
+
+	/*
+	 * See if the caller is being too lazy to figure out if
+	 * the transaction really needs an abort.
+	 */
+	if ((flags & XFS_TRANS_ABORT) && !(tp->t_flags & XFS_TRANS_DIRTY))
+		flags &= ~XFS_TRANS_ABORT;
+	/*
+	 * See if the caller is relying on us to shut down the
+	 * filesystem.  This happens in paths where we detect
+	 * corruption and decide to give up.
+	 */
+	if ((tp->t_flags & XFS_TRANS_DIRTY) &&
+	    !XFS_FORCED_SHUTDOWN(tp->t_mountp))
+		xfs_force_shutdown(tp->t_mountp, XFS_CORRUPT_INCORE);
+#ifdef DEBUG
+	if (!(flags & XFS_TRANS_ABORT)) {
+		licp = &(tp->t_items);
+		while (licp != NULL) {
+			lidp = licp->lic_descs;
+			for (i = 0; i < licp->lic_unused; i++, lidp++) {
+				if (XFS_LIC_ISFREE(licp, i)) {
+					continue;
+				}
+
+				lip = lidp->lid_item;
+				if (!XFS_FORCED_SHUTDOWN(tp->t_mountp))
+					ASSERT(!(lip->li_type == XFS_LI_EFD));
+			}
+			licp = licp->lic_next;
+		}
+	}
+#endif
+	xfs_trans_unreserve_and_mod_sb(tp);
+	XFS_TRANS_UNRESERVE_AND_MOD_DQUOTS(tp->t_mountp, tp);
+
+	if (tp->t_ticket) {
+		if (flags & XFS_TRANS_RELEASE_LOG_RES) {
+			ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
+			log_flags = XFS_LOG_REL_PERM_RESERV;
+		} else {
+			log_flags = 0;
+		}
+		xfs_log_done(tp->t_mountp, tp->t_ticket, NULL, log_flags);
+	}
+
+	/* mark this thread as no longer being in a transaction */
+        PFLAGS_RESTORE(&tp->t_pflags);
+
+	xfs_trans_free_items(tp, flags);
+	xfs_trans_free_busy(tp);
+	xfs_trans_free(tp);
+}
+
+
+/*
+ * Free the transaction structure.  If there is more clean up
+ * to do when the structure is freed, add it here.
+ */
+STATIC void
+xfs_trans_free(
+	xfs_trans_t	*tp)
+{
+	atomic_dec(&tp->t_mountp->m_active_trans);
+	XFS_TRANS_FREE_DQINFO(tp->t_mountp, tp);
+	kmem_zone_free(xfs_trans_zone, tp);
+}
+
+
+/*
+ * THIS SHOULD BE REWRITTEN TO USE xfs_trans_next_item().
+ *
+ * This is typically called by the LM when a transaction has been fully
+ * committed to disk.  It needs to unpin the items which have
+ * been logged by the transaction and update their positions
+ * in the AIL if necessary.
+ * This also gets called when the transactions didn't get written out
+ * because of an I/O error. Abortflag & XFS_LI_ABORTED is set then.
+ *
+ * Call xfs_trans_chunk_committed() to process the items in
+ * each chunk.
+ */
+STATIC void
+xfs_trans_committed(
+	xfs_trans_t	*tp,
+	int		abortflag)
+{
+	xfs_log_item_chunk_t	*licp;
+	xfs_log_item_chunk_t	*next_licp;
+	xfs_log_busy_chunk_t	*lbcp;
+	xfs_log_busy_slot_t	*lbsp;
+	int			i;
+
+	/*
+	 * Call the transaction's completion callback if there
+	 * is one.
+	 */
+	if (tp->t_callback != NULL) {
+		tp->t_callback(tp, tp->t_callarg);
+	}
+
+	/*
+	 * Special case the chunk embedded in the transaction.
+	 */
+	licp = &(tp->t_items);
+	if (!(XFS_LIC_ARE_ALL_FREE(licp))) {
+		xfs_trans_chunk_committed(licp, tp->t_lsn, abortflag);
+	}
+
+	/*
+	 * Process the items in each chunk in turn.
+	 */
+	licp = licp->lic_next;
+	while (licp != NULL) {
+		ASSERT(!XFS_LIC_ARE_ALL_FREE(licp));
+		xfs_trans_chunk_committed(licp, tp->t_lsn, abortflag);
+		next_licp = licp->lic_next;
+		kmem_free(licp, sizeof(xfs_log_item_chunk_t));
+		licp = next_licp;
+	}
+
+	/*
+	 * Clear all the per-AG busy list items listed in this transaction
+	 */
+	lbcp = &tp->t_busy;
+	while (lbcp != NULL) {
+		for (i = 0, lbsp = lbcp->lbc_busy; i < lbcp->lbc_unused; i++, lbsp++) {
+			if (!XFS_LBC_ISFREE(lbcp, i)) {
+				xfs_alloc_clear_busy(tp, lbsp->lbc_ag,
+						     lbsp->lbc_idx);
+			}
+		}
+		lbcp = lbcp->lbc_next;
+	}
+	xfs_trans_free_busy(tp);
+
+	/*
+	 * That's it for the transaction structure.  Free it.
+	 */
+	xfs_trans_free(tp);
+}
+
+/*
+ * This is called to perform the commit processing for each
+ * item described by the given chunk.
+ *
+ * The commit processing consists of unlocking items which were
+ * held locked with the SYNC_UNLOCK attribute, calling the committed
+ * routine of each logged item, updating the item's position in the AIL
+ * if necessary, and unpinning each item.  If the committed routine
+ * returns -1, then do nothing further with the item because it
+ * may have been freed.
+ *
+ * Since items are unlocked when they are copied to the incore
+ * log, it is possible for two transactions to be completing
+ * and manipulating the same item simultaneously.  The AIL lock
+ * will protect the lsn field of each item.  The value of this
+ * field can never go backwards.
+ *
+ * We unpin the items after repositioning them in the AIL, because
+ * otherwise they could be immediately flushed and we'd have to race
+ * with the flusher trying to pull the item from the AIL as we add it.
+ */
+STATIC void
+xfs_trans_chunk_committed(
+	xfs_log_item_chunk_t	*licp,
+	xfs_lsn_t		lsn,
+	int			aborted)
+{
+	xfs_log_item_desc_t	*lidp;
+	xfs_log_item_t		*lip;
+	xfs_lsn_t		item_lsn;
+	struct xfs_mount	*mp;
+	int			i;
+	SPLDECL(s);
+
+	lidp = licp->lic_descs;
+	for (i = 0; i < licp->lic_unused; i++, lidp++) {
+		if (XFS_LIC_ISFREE(licp, i)) {
+			continue;
+		}
+
+		lip = lidp->lid_item;
+		if (aborted)
+			lip->li_flags |= XFS_LI_ABORTED;
+
+		if (lidp->lid_flags & XFS_LID_SYNC_UNLOCK) {
+			IOP_UNLOCK(lip);
+		}
+
+		/*
+		 * Send in the ABORTED flag to the COMMITTED routine
+		 * so that it knows whether the transaction was aborted
+		 * or not.
+		 */
+		item_lsn = IOP_COMMITTED(lip, lsn);
+
+		/*
+		 * If the committed routine returns -1, make
+		 * no more references to the item.
+		 */
+		if (XFS_LSN_CMP(item_lsn, (xfs_lsn_t)-1) == 0) {
+			continue;
+		}
+
+		/*
+		 * If the returned lsn is greater than what it
+		 * contained before, update the location of the
+		 * item in the AIL.  If it is not, then do nothing.
+		 * Items can never move backwards in the AIL.
+		 *
+		 * While the new lsn should usually be greater, it
+		 * is possible that a later transaction completing
+		 * simultaneously with an earlier one using the
+		 * same item could complete first with a higher lsn.
+		 * This would cause the earlier transaction to fail
+		 * the test below.
+		 */
+		mp = lip->li_mountp;
+		AIL_LOCK(mp,s);
+		if (XFS_LSN_CMP(item_lsn, lip->li_lsn) > 0) {
+			/*
+			 * This will set the item's lsn to item_lsn
+			 * and update the position of the item in
+			 * the AIL.
+			 *
+			 * xfs_trans_update_ail() drops the AIL lock.
+			 */
+			xfs_trans_update_ail(mp, lip, item_lsn, s);
+		} else {
+			AIL_UNLOCK(mp, s);
+		}
+
+		/*
+		 * Now that we've repositioned the item in the AIL,
+		 * unpin it so it can be flushed. Pass information
+		 * about buffer stale state down from the log item
+		 * flags, if anyone else stales the buffer we do not
+		 * want to pay any attention to it.
+		 */
+		IOP_UNPIN(lip, lidp->lid_flags & XFS_LID_BUF_STALE);
+	}
+}
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)