xfs: simplify log item descriptor tracking

Currently we track log item descriptor belonging to a transaction using a
complex opencoded chunk allocator.  This code has been there since day one
and seems to work around the lack of an efficient slab allocator.

This patch replaces it with dynamically allocated log item descriptors
from a dedicated slab pool, linked to the transaction by a linked list.

This allows to greatly simplify the log item descriptor tracking to the
point where it's just a couple hundred lines in xfs_trans.c instead of
a separate file.  The external API has also been simplified while we're
at it - the xfs_trans_add_item and xfs_trans_del_item functions to add/
delete items from a transaction have been simplified to the bare minium,
and the xfs_trans_find_item function is replaced with a direct dereference
of the li_desc field.  All debug code walking the list of log items in
a transaction is down to a simple list_for_each_entry.

Note that we could easily use a singly linked list here instead of the
double linked list from list.h as the fastpath only does deletion from
sequential traversal.  But given that we don't have one available as
a library function yet I use the list.h functions for simplicity.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

13 files changed, 194 insertions, 759 deletions

diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index a5239b1713b..0dce969d6ca 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -87,7 +87,6 @@ xfs-y				+= xfs_alloc.o \
 				   xfs_trans_buf.o \
 				   xfs_trans_extfree.o \
 				   xfs_trans_inode.o \
-				   xfs_trans_item.o \
 				   xfs_utils.o \
 				   xfs_vnodeops.o \
 				   xfs_rw.o
diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c
index 5593066d497..4b90e4b531b 100644
--- a/fs/xfs/linux-2.6/xfs_super.c
+++ b/fs/xfs/linux-2.6/xfs_super.c
@@ -1703,6 +1703,12 @@ xfs_init_zones(void)
 	if (!xfs_trans_zone)
 		goto out_destroy_ifork_zone;
 
+	xfs_log_item_desc_zone =
+		kmem_zone_init(sizeof(struct xfs_log_item_desc),
+			       "xfs_log_item_desc");
+	if (!xfs_log_item_desc_zone)
+		goto out_destroy_trans_zone;
+
 	/*
 	 * The size of the zone allocated buf log item is the maximum
 	 * size possible under XFS.  This wastes a little bit of memory,
@@ -1712,7 +1718,7 @@ xfs_init_zones(void)
 				(((XFS_MAX_BLOCKSIZE / XFS_BLF_CHUNK) /
 				  NBWORD) * sizeof(int))), "xfs_buf_item");
 	if (!xfs_buf_item_zone)
-		goto out_destroy_trans_zone;
+		goto out_destroy_log_item_desc_zone;
 
 	xfs_efd_zone = kmem_zone_init((sizeof(xfs_efd_log_item_t) +
 			((XFS_EFD_MAX_FAST_EXTENTS - 1) *
@@ -1749,6 +1755,8 @@ xfs_init_zones(void)
 	kmem_zone_destroy(xfs_efd_zone);
  out_destroy_buf_item_zone:
 	kmem_zone_destroy(xfs_buf_item_zone);
+ out_destroy_log_item_desc_zone:
+	kmem_zone_destroy(xfs_log_item_desc_zone);
  out_destroy_trans_zone:
 	kmem_zone_destroy(xfs_trans_zone);
  out_destroy_ifork_zone:
@@ -1779,6 +1787,7 @@ xfs_destroy_zones(void)
 	kmem_zone_destroy(xfs_efi_zone);
 	kmem_zone_destroy(xfs_efd_zone);
 	kmem_zone_destroy(xfs_buf_item_zone);
+	kmem_zone_destroy(xfs_log_item_desc_zone);
 	kmem_zone_destroy(xfs_trans_zone);
 	kmem_zone_destroy(xfs_ifork_zone);
 	kmem_zone_destroy(xfs_dabuf_zone);
diff --git a/fs/xfs/quota/xfs_trans_dquot.c b/fs/xfs/quota/xfs_trans_dquot.c
index 08f5604d092..7de91d1b75c 100644
--- a/fs/xfs/quota/xfs_trans_dquot.c
+++ b/fs/xfs/quota/xfs_trans_dquot.c
@@ -49,16 +49,14 @@ xfs_trans_dqjoin(
 	xfs_trans_t	*tp,
 	xfs_dquot_t	*dqp)
 {
-	xfs_dq_logitem_t    *lp = &dqp->q_logitem;
-
 	ASSERT(dqp->q_transp != tp);
 	ASSERT(XFS_DQ_IS_LOCKED(dqp));
-	ASSERT(lp->qli_dquot == dqp);
+	ASSERT(dqp->q_logitem.qli_dquot == dqp);
 
 	/*
 	 * Get a log_item_desc to point at the new item.
 	 */
-	(void) xfs_trans_add_item(tp, (xfs_log_item_t*)(lp));
+	xfs_trans_add_item(tp, &dqp->q_logitem.qli_item);
 
 	/*
 	 * Initialize i_transp so we can later determine if this dquot is
@@ -83,16 +81,11 @@ xfs_trans_log_dquot(
 	xfs_trans_t	*tp,
 	xfs_dquot_t	*dqp)
 {
-	xfs_log_item_desc_t	*lidp;
-
 	ASSERT(dqp->q_transp == tp);
 	ASSERT(XFS_DQ_IS_LOCKED(dqp));
 
-	lidp = xfs_trans_find_item(tp, (xfs_log_item_t*)(&dqp->q_logitem));
-	ASSERT(lidp != NULL);
-
 	tp->t_flags |= XFS_TRANS_DIRTY;
-	lidp->lid_flags |= XFS_LID_DIRTY;
+	dqp->q_logitem.qli_item.li_desc->lid_flags |= XFS_LID_DIRTY;
 }
 
 /*
@@ -864,9 +857,8 @@ xfs_trans_get_qoff_item(
 	/*
 	 * Get a log_item_desc to point at the new item.
 	 */
-	(void) xfs_trans_add_item(tp, (xfs_log_item_t*)q);
-
-	return (q);
+	xfs_trans_add_item(tp, &q->qql_item);
+	return q;
 }
 
 
@@ -880,13 +872,8 @@ xfs_trans_log_quotaoff_item(
 	xfs_trans_t		*tp,
 	xfs_qoff_logitem_t	*qlp)
 {
-	xfs_log_item_desc_t	*lidp;
-
-	lidp = xfs_trans_find_item(tp, (xfs_log_item_t *)qlp);
-	ASSERT(lidp != NULL);
-
 	tp->t_flags |= XFS_TRANS_DIRTY;
-	lidp->lid_flags |= XFS_LID_DIRTY;
+	qlp->qql_item.li_desc->lid_flags |= XFS_LID_DIRTY;
 }
 
 STATIC void
diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c
index ed4e3ae2c1d..ff8675b4197 100644
--- a/fs/xfs/xfs_bmap.c
+++ b/fs/xfs/xfs_bmap.c
@@ -5857,43 +5857,18 @@ xfs_bmap_get_bp(
 		bp = NULL;
 
 	if (!bp) { /* Chase down all the log items to see if the bp is there */
-		xfs_log_item_chunk_t    *licp;
-		xfs_trans_t		*tp;
-
-		tp = cur->bc_tp;
-		licp = &tp->t_items;
-		while (!bp && licp != NULL) {
-			if (xfs_lic_are_all_free(licp)) {
-				licp = licp->lic_next;
-				continue;
-			}
-			for (i = 0; i < licp->lic_unused; i++) {
-				xfs_log_item_desc_t	*lidp;
-				xfs_log_item_t		*lip;
-				xfs_buf_log_item_t	*bip;
-				xfs_buf_t		*lbp;
-
-				if (xfs_lic_isfree(licp, i)) {
-					continue;
-				}
-
-				lidp = xfs_lic_slot(licp, i);
-				lip = lidp->lid_item;
-				if (lip->li_type != XFS_LI_BUF)
-					continue;
-
-				bip = (xfs_buf_log_item_t *)lip;
-				lbp = bip->bli_buf;
-
-				if (XFS_BUF_ADDR(lbp) == bno) {
-					bp = lbp;
-					break; /* Found it */
-				}
-			}
-			licp = licp->lic_next;
+		struct xfs_log_item_desc *lidp;
+		struct xfs_buf_log_item	*bip;
+
+		list_for_each_entry(lidp, &cur->bc_tp->t_items, lid_trans) {
+			bip = (struct xfs_buf_log_item *)lidp->lid_item;
+			if (bip->bli_item.li_type == XFS_LI_BUF &&
+			    XFS_BUF_ADDR(bip->bli_buf) == bno)
+				return bip->bli_buf;
 		}
 	}
-	return(bp);
+
+	return bp;
 }
 
 STATIC void
diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index 91ad92e83bc..711f69abbbe 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -460,13 +460,10 @@ xfs_buf_item_unpin_remove(
 		 * occurs later in the xfs_trans_uncommit() will try to
 		 * reference the buffer which we no longer have a hold on.
 		 */
-		struct xfs_log_item_desc *lidp;
-
 		ASSERT(XFS_BUF_VALUSEMA(bip->bli_buf) <= 0);
 		trace_xfs_buf_item_unpin_stale(bip);
 
-		lidp = xfs_trans_find_item(tp, (xfs_log_item_t *)bip);
-		xfs_trans_free_item(tp, lidp);
+		xfs_trans_del_item(&bip->bli_item);
 
 		/*
 		 * Since the transaction no longer refers to the buffer, the
diff --git a/fs/xfs/xfs_extfree_item.c b/fs/xfs/xfs_extfree_item.c
index 1023b1fadfe..8d0e543ca3c 100644
--- a/fs/xfs/xfs_extfree_item.c
+++ b/fs/xfs/xfs_extfree_item.c
@@ -131,18 +131,18 @@ STATIC void
 xfs_efi_item_unpin_remove(xfs_efi_log_item_t *efip, xfs_trans_t *tp)
 {
 	struct xfs_ail		*ailp = efip->efi_item.li_ailp;
-	xfs_log_item_desc_t	*lidp;
 
 	spin_lock(&ailp->xa_lock);
 	if (efip->efi_flags & XFS_EFI_CANCELED) {
+		struct xfs_log_item	*lip = &efip->efi_item;
+
 		/*
 		 * 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);
+		xfs_trans_del_item(lip);
 
 		/* xfs_trans_ail_delete() drops the AIL lock. */
-		xfs_trans_ail_delete(ailp, (xfs_log_item_t *)efip);
+		xfs_trans_ail_delete(ailp, lip);
 		xfs_efi_item_free(efip);
 	} else {
 		efip->efi_flags |= XFS_EFI_COMMITTED;
diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index 57c53f7ad2c..9c41efccf72 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
+ * Copyright (C) 2010 Red Hat, Inc.
  * All Rights Reserved.
  *
  * This program is free software; you can redistribute it and/or
@@ -43,6 +44,7 @@
 #include "xfs_trace.h"
 
 kmem_zone_t	*xfs_trans_zone;
+kmem_zone_t	*xfs_log_item_desc_zone;
 
 
 /*
@@ -593,8 +595,7 @@ _xfs_trans_alloc(
 	tp->t_magic = XFS_TRANS_MAGIC;
 	tp->t_type = type;
 	tp->t_mountp = mp;
-	tp->t_items_free = XFS_LIC_NUM_SLOTS;
-	xfs_lic_init(&(tp->t_items));
+	INIT_LIST_HEAD(&tp->t_items);
 	INIT_LIST_HEAD(&tp->t_busy);
 	return tp;
 }
@@ -639,8 +640,7 @@ xfs_trans_dup(
 	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;
-	xfs_lic_init(&(ntp->t_items));
+	INIT_LIST_HEAD(&ntp->t_items);
 	INIT_LIST_HEAD(&ntp->t_busy);
 
 	ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
@@ -1120,6 +1120,108 @@ xfs_trans_unreserve_and_mod_sb(
 }
 
 /*
+ * Add the given log item to the transaction's list of log items.
+ *
+ * The log item will now point to its new descriptor with its li_desc field.
+ */
+void
+xfs_trans_add_item(
+	struct xfs_trans	*tp,
+	struct xfs_log_item	*lip)
+{
+	struct xfs_log_item_desc *lidp;
+
+	ASSERT(lip->li_mountp = tp->t_mountp);
+	ASSERT(lip->li_ailp = tp->t_mountp->m_ail);
+
+	lidp = kmem_zone_zalloc(xfs_log_item_desc_zone, KM_SLEEP);
+
+	lidp->lid_item = lip;
+	lidp->lid_flags = 0;
+	lidp->lid_size = 0;
+	list_add_tail(&lidp->lid_trans, &tp->t_items);
+
+	lip->li_desc = lidp;
+}
+
+STATIC void
+xfs_trans_free_item_desc(
+	struct xfs_log_item_desc *lidp)
+{
+	list_del_init(&lidp->lid_trans);
+	kmem_zone_free(xfs_log_item_desc_zone, lidp);
+}
+
+/*
+ * Unlink and free the given descriptor.
+ */
+void
+xfs_trans_del_item(
+	struct xfs_log_item	*lip)
+{
+	xfs_trans_free_item_desc(lip->li_desc);
+	lip->li_desc = NULL;
+}
+
+/*
+ * Unlock all of the items of a transaction and free all the descriptors
+ * of that transaction.
+ */
+STATIC void
+xfs_trans_free_items(
+	struct xfs_trans	*tp,
+	xfs_lsn_t		commit_lsn,
+	int			flags)
+{
+	struct xfs_log_item_desc *lidp, *next;
+
+	list_for_each_entry_safe(lidp, next, &tp->t_items, lid_trans) {
+		struct xfs_log_item	*lip = lidp->lid_item;
+
+		lip->li_desc = NULL;
+
+		if (commit_lsn != NULLCOMMITLSN)
+			IOP_COMMITTING(lip, commit_lsn);
+		if (flags & XFS_TRANS_ABORT)
+			lip->li_flags |= XFS_LI_ABORTED;
+		IOP_UNLOCK(lip);
+
+		xfs_trans_free_item_desc(lidp);
+	}
+}
+
+/*
+ * Unlock the items associated with a transaction.
+ *
+ * Items which were not logged should be freed.  Those which were logged must
+ * still be tracked so they can be unpinned when the transaction commits.
+ */
+STATIC void
+xfs_trans_unlock_items(
+	struct xfs_trans	*tp,
+	xfs_lsn_t		commit_lsn)
+{
+	struct xfs_log_item_desc *lidp, *next;
+
+	list_for_each_entry_safe(lidp, next, &tp->t_items, lid_trans) {
+		struct xfs_log_item	*lip = lidp->lid_item;
+
+		lip->li_desc = NULL;
+
+		if (commit_lsn != NULLCOMMITLSN)
+			IOP_COMMITTING(lip, commit_lsn);
+		IOP_UNLOCK(lip);
+
+		/*
+		 * Free the descriptor if the item is not dirty
+		 * within this transaction.
+		 */
+		if (!(lidp->lid_flags & XFS_LID_DIRTY))
+			xfs_trans_free_item_desc(lidp);
+	}
+}
+
+/*
  * 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
@@ -1130,30 +1232,27 @@ xfs_trans_count_vecs(
 	struct xfs_trans	*tp)
 {
 	int			nvecs;
-	xfs_log_item_desc_t	*lidp;
+	struct xfs_log_item_desc *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)
+	if (list_empty(&tp->t_items)) {
+		ASSERT(0);
 		return 0;
+	}
 
-	while (lidp != NULL) {
+	list_for_each_entry(lidp, &tp->t_items, lid_trans) {
 		/*
 		 * Skip items which aren't dirty in this transaction.
 		 */
-		if (!(lidp->lid_flags & XFS_LID_DIRTY)) {
-			lidp = xfs_trans_next_item(tp, lidp);
+		if (!(lidp->lid_flags & XFS_LID_DIRTY))
 			continue;
-		}
 		lidp->lid_size = IOP_SIZE(lidp->lid_item);
 		nvecs += lidp->lid_size;
-		lidp = xfs_trans_next_item(tp, lidp);
 	}
 
 	return nvecs;
@@ -1173,7 +1272,7 @@ xfs_trans_fill_vecs(
 	struct xfs_trans	*tp,
 	struct xfs_log_iovec	*log_vector)
 {
-	xfs_log_item_desc_t	*lidp;
+	struct xfs_log_item_desc *lidp;
 	struct xfs_log_iovec	*vecp;
 	uint			nitems;
 
@@ -1184,14 +1283,11 @@ xfs_trans_fill_vecs(
 	vecp = log_vector + 1;
 
 	nitems = 0;
-	lidp = xfs_trans_first_item(tp);
-	ASSERT(lidp);
-	while (lidp) {
+	ASSERT(!list_empty(&tp->t_items));
+	list_for_each_entry(lidp, &tp->t_items, lid_trans) {
 		/* Skip items which aren't dirty in this transaction. */
-		if (!(lidp->lid_flags & XFS_LID_DIRTY)) {
-			lidp = xfs_trans_next_item(tp, lidp);
+		if (!(lidp->lid_flags & XFS_LID_DIRTY))
 			continue;
-		}
 
 		/*
 		 * The item may be marked dirty but not log anything.  This can
@@ -1202,7 +1298,6 @@ xfs_trans_fill_vecs(
 		IOP_FORMAT(lidp->lid_item, vecp);
 		vecp += lidp->lid_size;
 		IOP_PIN(lidp->lid_item);
-		lidp = xfs_trans_next_item(tp, lidp);
 	}
 
 	/*
@@ -1297,24 +1392,15 @@ xfs_trans_committed(
 	struct xfs_trans	*tp,
 	int			abortflag)
 {
-	xfs_log_item_desc_t	*lidp;
-	xfs_log_item_chunk_t	*licp;
-	xfs_log_item_chunk_t	*next_licp;
+	struct xfs_log_item_desc *lidp, *next;
 
 	/* Call the transaction's completion callback if there is one. */
 	if (tp->t_callback != NULL)
 		tp->t_callback(tp, tp->t_callarg);
 
-	for (lidp = xfs_trans_first_item(tp);
-	     lidp != NULL;
-	     lidp = xfs_trans_next_item(tp, lidp)) {
+	list_for_each_entry_safe(lidp, next, &tp->t_items, lid_trans) {
 		xfs_trans_item_committed(lidp->lid_item, tp->t_lsn, abortflag);
-	}
-
-	/* free the item chunks, ignoring the embedded chunk */
-	for (licp = tp->t_items.lic_next; licp != NULL; licp = next_licp) {
-		next_licp = licp->lic_next;
-		kmem_free(licp);
+		xfs_trans_free_item_desc(lidp);
 	}
 
 	xfs_trans_free(tp);
@@ -1329,11 +1415,9 @@ xfs_trans_uncommit(
 	struct xfs_trans	*tp,
 	uint			flags)
 {
-	xfs_log_item_desc_t	*lidp;
+	struct xfs_log_item_desc *lidp;
 
-	for (lidp = xfs_trans_first_item(tp);
-	     lidp != NULL;
-	     lidp = xfs_trans_next_item(tp, lidp)) {
+	list_for_each_entry(lidp, &tp->t_items, lid_trans) {
 		/*
 		 * Unpin all but those that aren't dirty.
 		 */
@@ -1504,33 +1588,28 @@ STATIC struct xfs_log_vec *
 xfs_trans_alloc_log_vecs(
 	xfs_trans_t	*tp)
 {
-	xfs_log_item_desc_t	*lidp;
+	struct xfs_log_item_desc *lidp;
 	struct xfs_log_vec	*lv = NULL;
 	struct xfs_log_vec	*ret_lv = NULL;
 
-	lidp = xfs_trans_first_item(tp);
 
 	/* Bail out if we didn't find a log item.  */
-	if (!lidp) {
+	if (list_empty(&tp->t_items)) {
 		ASSERT(0);
 		return NULL;
 	}
 
-	while (lidp != NULL) {
+	list_for_each_entry(lidp, &tp->t_items, lid_trans) {
 		struct xfs_log_vec *new_lv;
 
 		/* Skip items which aren't dirty in this transaction. */
-		if (!(lidp->lid_flags & XFS_LID_DIRTY)) {
-			lidp = xfs_trans_next_item(tp, lidp);
+		if (!(lidp->lid_flags & XFS_LID_DIRTY))
 			continue;
-		}
 
 		/* Skip items that do not have any vectors for writing */
 		lidp->lid_size = IOP_SIZE(lidp->lid_item);
-		if (!lidp->lid_size) {
-			lidp = xfs_trans_next_item(tp, lidp);
+		if (!lidp->lid_size)
 			continue;
-		}
 
 		new_lv = kmem_zalloc(sizeof(*new_lv) +
 				lidp->lid_size * sizeof(struct xfs_log_iovec),
@@ -1545,7 +1624,6 @@ xfs_trans_alloc_log_vecs(
 		else
 			lv->lv_next = new_lv;
 		lv = new_lv;
-		lidp = xfs_trans_next_item(tp, lidp);
 	}
 
 	return ret_lv;
@@ -1704,12 +1782,6 @@ xfs_trans_cancel(
 	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
 	xfs_mount_t		*mp = tp->t_mountp;
 
 	/*
@@ -1728,21 +1800,11 @@ xfs_trans_cancel(
 		xfs_force_shutdown(mp, SHUTDOWN_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(mp))
-					ASSERT(!(lip->li_type == XFS_LI_EFD));
-			}
-			licp = licp->lic_next;
-		}
+	if (!(flags & XFS_TRANS_ABORT) && !XFS_FORCED_SHUTDOWN(mp)) {
+		struct xfs_log_item_desc *lidp;
+
+		list_for_each_entry(lidp, &tp->t_items, lid_trans)
+			ASSERT(!(lidp->lid_item->li_type == XFS_LI_EFD));
 	}
 #endif
 	xfs_trans_unreserve_and_mod_sb(tp);
diff --git a/fs/xfs/xfs_trans.h b/fs/xfs/xfs_trans.h
index e639e8e9a2a..0c903eb8bbe 100644
--- a/fs/xfs/xfs_trans.h
+++ b/fs/xfs/xfs_trans.h
@@ -161,105 +161,14 @@ typedef struct xfs_trans_header {
  * the amount of space needed to log the item it describes
  * once we get to commit processing (see xfs_trans_commit()).
  */
-typedef struct xfs_log_item_desc {
+struct xfs_log_item_desc {
 	struct xfs_log_item	*lid_item;
-	ushort		lid_size;
-	unsigned char	lid_flags;
-	unsigned char	lid_index;
-} xfs_log_item_desc_t;
+	ushort			lid_size;
+	unsigned char		lid_flags;
+	struct list_head	lid_trans;
+};
 
 #define XFS_LID_DIRTY		0x1
-#define XFS_LID_PINNED		0x2
-
-/*
- * This structure is used to maintain a chunk list of log_item_desc
- * structures. The free field is a bitmask indicating which descriptors
- * in this chunk's array are free.  The unused field is the first value
- * not used since this chunk was allocated.
- */
-#define	XFS_LIC_NUM_SLOTS	15
-typedef struct xfs_log_item_chunk {
-	struct xfs_log_item_chunk	*lic_next;
-	ushort				lic_free;
-	ushort				lic_unused;
-	xfs_log_item_desc_t		lic_descs[XFS_LIC_NUM_SLOTS];
-} xfs_log_item_chunk_t;
-
-#define	XFS_LIC_MAX_SLOT	(XFS_LIC_NUM_SLOTS - 1)
-#define	XFS_LIC_FREEMASK	((1 << XFS_LIC_NUM_SLOTS) - 1)
-
-
-/*
- * Initialize the given chunk.  Set the chunk's free descriptor mask
- * to indicate that all descriptors are free.  The caller gets to set
- * lic_unused to the right value (0 matches all free).  The
- * lic_descs.lid_index values are set up as each desc is allocated.
- */
-static inline void xfs_lic_init(xfs_log_item_chunk_t *cp)
-{
-	cp->lic_free = XFS_LIC_FREEMASK;
-}
-
-static inline void xfs_lic_init_slot(xfs_log_item_chunk_t *cp, int slot)
-{
-	cp->lic_descs[slot].lid_index = (unsigned char)(slot);
-}
-
-static inline int xfs_lic_vacancy(xfs_log_item_chunk_t *cp)
-{
-	return cp->lic_free & XFS_LIC_FREEMASK;
-}
-
-static inline void xfs_lic_all_free(xfs_log_item_chunk_t *cp)
-{
-	cp->lic_free = XFS_LIC_FREEMASK;
-}
-
-static inline int xfs_lic_are_all_free(xfs_log_item_chunk_t *cp)
-{
-	return ((cp->lic_free & XFS_LIC_FREEMASK) == XFS_LIC_FREEMASK);
-}
-
-static inline int xfs_lic_isfree(xfs_log_item_chunk_t *cp, int slot)
-{
-	return (cp->lic_free & (1 << slot));
-}
-
-static inline void xfs_lic_claim(xfs_log_item_chunk_t *cp, int slot)
-{
-	cp->lic_free &= ~(1 << slot);
-}
-
-static inline void xfs_lic_relse(xfs_log_item_chunk_t *cp, int slot)
-{
-	cp->lic_free |= 1 << slot;
-}
-
-static inline xfs_log_item_desc_t *
-xfs_lic_slot(xfs_log_item_chunk_t *cp, int slot)
-{
-	return &(cp->lic_descs[slot]);
-}
-
-static inline int xfs_lic_desc_to_slot(xfs_log_item_desc_t *dp)
-{
-	return (uint)dp->lid_index;
-}
-
-/*
- * Calculate the address of a chunk given a descriptor pointer:
- * dp - dp->lid_index give the address of the start of the lic_descs array.
- * From this we subtract the offset of the lic_descs field in a chunk.
- * All of this yields the address of the chunk, which is
- * cast to a chunk pointer.
- */
-static inline xfs_log_item_chunk_t *
-xfs_lic_desc_to_chunk(xfs_log_item_desc_t *dp)
-{
-	return (xfs_log_item_chunk_t*) \
-		(((xfs_caddr_t)((dp) - (dp)->lid_index)) - \
-		(xfs_caddr_t)(((xfs_log_item_chunk_t*)0)->lic_descs));
-}
 
 #define	XFS_TRANS_MAGIC		0x5452414E	/* 'TRAN' */
 /*
@@ -516,8 +425,7 @@ typedef struct xfs_trans {
 	int64_t			t_rblocks_delta;/* superblock rblocks change */
 	int64_t			t_rextents_delta;/* superblocks rextents chg */
 	int64_t			t_rextslog_delta;/* superblocks rextslog chg */
-	unsigned int		t_items_free;	/* log item descs free */
-	xfs_log_item_chunk_t	t_items;	/* first log item desc chunk */
+	struct list_head	t_items;	/* log item descriptors */
 	xfs_trans_header_t	t_header;	/* header for in-log trans */
 	struct list_head	t_busy;		/* list of busy extents */
 	unsigned long		t_pflags;	/* saved process flags state */
@@ -595,6 +503,7 @@ int		xfs_trans_ail_init(struct xfs_mount *);
 void		xfs_trans_ail_destroy(struct xfs_mount *);
 
 extern kmem_zone_t	*xfs_trans_zone;
+extern kmem_zone_t	*xfs_log_item_desc_zone;
 
 #endif	/* __KERNEL__ */
 
diff --git a/fs/xfs/xfs_trans_buf.c b/fs/xfs/xfs_trans_buf.c
index d1d08aa404b..74a1c33e409 100644
--- a/fs/xfs/xfs_trans_buf.c
+++ b/fs/xfs/xfs_trans_buf.c
@@ -47,36 +47,17 @@ xfs_trans_buf_item_match(
 	xfs_daddr_t		blkno,
 	int			len)
 {
-	xfs_log_item_chunk_t	*licp;
-	xfs_log_item_desc_t	*lidp;
-	xfs_buf_log_item_t	*blip;
-	int			i;
+	struct xfs_log_item_desc *lidp;
+	struct xfs_buf_log_item	*blip;
 
 	len = BBTOB(len);
-	for (licp = &tp->t_items; licp != NULL; licp = licp->lic_next) {
-		if (xfs_lic_are_all_free(licp)) {
-			ASSERT(licp == &tp->t_items);
-			ASSERT(licp->lic_next == NULL);
-			return NULL;
-		}
-
-		for (i = 0; i < licp->lic_unused; i++) {
-			/*
-			 * Skip unoccupied slots.
-			 */
-			if (xfs_lic_isfree(licp, i))
-				continue;
-
-			lidp = xfs_lic_slot(licp, i);
-			blip = (xfs_buf_log_item_t *)lidp->lid_item;
-			if (blip->bli_item.li_type != XFS_LI_BUF)
-				continue;
-
-			if (XFS_BUF_TARGET(blip->bli_buf) == target &&
-			    XFS_BUF_ADDR(blip->bli_buf) == blkno &&
-			    XFS_BUF_COUNT(blip->bli_buf) == len)
-				return blip->bli_buf;
-		}
+	list_for_each_entry(lidp, &tp->t_items, lid_trans) {
+		blip = (struct xfs_buf_log_item *)lidp->lid_item;
+		if (blip->bli_item.li_type == XFS_LI_BUF &&
+		    XFS_BUF_TARGET(blip->bli_buf) == target &&
+		    XFS_BUF_ADDR(blip->bli_buf) == blkno &&
+		    XFS_BUF_COUNT(blip->bli_buf) == len)
+			return blip->bli_buf;
 	}
 
 	return NULL;
@@ -123,7 +104,7 @@ _xfs_trans_bjoin(
 	/*
 	 * Get a log_item_desc to point at the new item.
 	 */
-	(void) xfs_trans_add_item(tp, (xfs_log_item_t *)bip);
+	xfs_trans_add_item(tp, &bip->bli_item);
 
 	/*
 	 * Initialize b_fsprivate2 so we can find it with incore_match()
@@ -479,7 +460,6 @@ xfs_trans_brelse(xfs_trans_t	*tp,
 {
 	xfs_buf_log_item_t	*bip;
 	xfs_log_item_t		*lip;
-	xfs_log_item_desc_t	*lidp;
 
 	/*
 	 * Default to a normal brelse() call if the tp is NULL.
@@ -510,13 +490,6 @@ xfs_trans_brelse(xfs_trans_t	*tp,
 	ASSERT(!(bip->bli_format.blf_flags & XFS_BLF_CANCEL));
 	ASSERT(atomic_read(&bip->bli_refcount) > 0);
 
-	/*
-	 * Find the item descriptor pointing to this buffer's
-	 * log item.  It must be there.
-	 */
-	lidp = xfs_trans_find_item(tp, (xfs_log_item_t*)bip);
-	ASSERT(lidp != NULL);
-
 	trace_xfs_trans_brelse(bip);
 
 	/*
@@ -532,7 +505,7 @@ xfs_trans_brelse(xfs_trans_t	*tp,
 	 * If the buffer is dirty within this transaction, we can't
 	 * release it until we commit.
 	 */
-	if (lidp->lid_flags & XFS_LID_DIRTY)
+	if (bip->bli_item.li_desc->lid_flags & XFS_LID_DIRTY)
 		return;
 
 	/*
@@ -549,7 +522,7 @@ xfs_trans_brelse(xfs_trans_t	*tp,
 	/*
 	 * Free up the log item descriptor tracking the released item.
 	 */
-	xfs_trans_free_item(tp, lidp);
+	xfs_trans_del_item(&bip->bli_item);
 
 	/*
 	 * Clear the hold flag in the buf log item if it is set.
@@ -661,7 +634,6 @@ xfs_trans_log_buf(xfs_trans_t	*tp,
 		  uint		last)
 {
 	xfs_buf_log_item_t	*bip;
-	xfs_log_item_desc_t	*lidp;
 
 	ASSERT(XFS_BUF_ISBUSY(bp));
 	ASSERT(XFS_BUF_FSPRIVATE2(bp, xfs_trans_t *) == tp);
@@ -703,11 +675,8 @@ xfs_trans_log_buf(xfs_trans_t	*tp,
 		bip->bli_format.blf_flags &= ~XFS_BLF_CANCEL;
 	}
 
-	lidp = xfs_trans_find_item(tp, (xfs_log_item_t*)bip);
-	ASSERT(lidp != NULL);
-
 	tp->t_flags |= XFS_TRANS_DIRTY;
-	lidp->lid_flags |= XFS_LID_DIRTY;
+	bip->bli_item.li_desc->lid_flags |= XFS_LID_DIRTY;
 	bip->bli_flags |= XFS_BLI_LOGGED;
 	xfs_buf_item_log(bip, first, last);
 }
@@ -736,7 +705,6 @@ xfs_trans_binval(
 	xfs_trans_t	*tp,
 	xfs_buf_t	*bp)
 {
-	xfs_log_item_desc_t	*lidp;
 	xfs_buf_log_item_t	*bip;
 
 	ASSERT(XFS_BUF_ISBUSY(bp));
@@ -744,8 +712,6 @@ xfs_trans_binval(
 	ASSERT(XFS_BUF_FSPRIVATE(bp, void *) != NULL);
 
 	bip = XFS_BUF_FSPRIVATE(bp, xfs_buf_log_item_t *);
-	lidp = xfs_trans_find_item(tp, (xfs_log_item_t*)bip);
-	ASSERT(lidp != NULL);
 	ASSERT(atomic_read(&bip->bli_refcount) > 0);
 
 	trace_xfs_trans_binval(bip);
@@ -760,7 +726,7 @@ xfs_trans_binval(
 		ASSERT(!(bip->bli_flags & (XFS_BLI_LOGGED | XFS_BLI_DIRTY)));
 		ASSERT(!(bip->bli_format.blf_flags & XFS_BLF_INODE_BUF));
 		ASSERT(bip->bli_format.blf_flags & XFS_BLF_CANCEL);
-		ASSERT(lidp->lid_flags & XFS_LID_DIRTY);
+		ASSERT(bip->bli_item.li_desc->lid_flags & XFS_LID_DIRTY);
 		ASSERT(tp->t_flags & XFS_TRANS_DIRTY);
 		return;
 	}
@@ -793,7 +759,7 @@ xfs_trans_binval(
 	bip->bli_format.blf_flags |= XFS_BLF_CANCEL;
 	memset((char *)(bip->bli_format.blf_data_map), 0,
 	      (bip->bli_format.blf_map_size * sizeof(uint)));
-	lidp->lid_flags |= XFS_LID_DIRTY;
+	bip->bli_item.li_desc->lid_flags |= XFS_LID_DIRTY;
 	tp->t_flags |= XFS_TRANS_DIRTY;
 }
 
diff --git a/fs/xfs/xfs_trans_extfree.c b/fs/xfs/xfs_trans_extfree.c
index dfb6a0fdcf9..f783d5e9fa7 100644
--- a/fs/xfs/xfs_trans_extfree.c
+++ b/fs/xfs/xfs_trans_extfree.c
@@ -48,9 +48,8 @@ xfs_trans_get_efi(xfs_trans_t	*tp,
 	/*
 	 * Get a log_item_desc to point at the new item.
 	 */
-	(void) xfs_trans_add_item(tp, (xfs_log_item_t*)efip);
-
-	return (efip);
+	xfs_trans_add_item(tp, &efip->efi_item);
+	return efip;
 }
 
 /*
@@ -64,15 +63,11 @@ xfs_trans_log_efi_extent(xfs_trans_t		*tp,
 			 xfs_fsblock_t		start_block,
 			 xfs_extlen_t		ext_len)
 {
-	xfs_log_item_desc_t	*lidp;
 	uint			next_extent;
 	xfs_extent_t		*extp;
 
-	lidp = xfs_trans_find_item(tp, (xfs_log_item_t*)efip);
-	ASSERT(lidp != NULL);
-
 	tp->t_flags |= XFS_TRANS_DIRTY;
-	lidp->lid_flags |= XFS_LID_DIRTY;
+	efip->efi_item.li_desc->lid_flags |= XFS_LID_DIRTY;
 
 	next_extent = efip->efi_next_extent;
 	ASSERT(next_extent < efip->efi_format.efi_nextents);
@@ -105,9 +100,8 @@ xfs_trans_get_efd(xfs_trans_t		*tp,
 	/*
 	 * Get a log_item_desc to point at the new item.
 	 */
-	(void) xfs_trans_add_item(tp, (xfs_log_item_t*)efdp);
-
-	return (efdp);
+	xfs_trans_add_item(tp, &efdp->efd_item);
+	return efdp;
 }
 
 /*
@@ -121,15 +115,11 @@ xfs_trans_log_efd_extent(xfs_trans_t		*tp,
 			 xfs_fsblock_t		start_block,
 			 xfs_extlen_t		ext_len)
 {
-	xfs_log_item_desc_t	*lidp;
 	uint			next_extent;
 	xfs_extent_t		*extp;
 
-	lidp = xfs_trans_find_item(tp, (xfs_log_item_t*)efdp);
-	ASSERT(lidp != NULL);
-
 	tp->t_flags |= XFS_TRANS_DIRTY;
-	lidp->lid_flags |= XFS_LID_DIRTY;
+	efdp->efd_item.li_desc->lid_flags |= XFS_LID_DIRTY;
 
 	next_extent = efdp->efd_next_extent;
 	ASSERT(next_extent < efdp->efd_format.efd_nextents);
diff --git a/fs/xfs/xfs_trans_inode.c b/fs/xfs/xfs_trans_inode.c
index 04cc08a1b66..865eeb63ce1 100644
--- a/fs/xfs/xfs_trans_inode.c
+++ b/fs/xfs/xfs_trans_inode.c
@@ -88,7 +88,7 @@ xfs_trans_ijoin(
 	/*
 	 * Get a log_item_desc to point at the new item.
 	 */
-	(void) xfs_trans_add_item(tp, (xfs_log_item_t*)(iip));
+	xfs_trans_add_item(tp, &iip->ili_item);
 
 	xfs_trans_inode_broot_debug(ip);
 
@@ -144,17 +144,12 @@ xfs_trans_log_inode(
 	xfs_inode_t	*ip,
 	uint		flags)
 {
-	xfs_log_item_desc_t	*lidp;
-
 	ASSERT(ip->i_transp == tp);
 	ASSERT(ip->i_itemp != NULL);
 	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
 
-	lidp = xfs_trans_find_item(tp, (xfs_log_item_t*)(ip->i_itemp));
-	ASSERT(lidp != NULL);
-
 	tp->t_flags |= XFS_TRANS_DIRTY;
-	lidp->lid_flags |= XFS_LID_DIRTY;
+	ip->i_itemp->ili_item.li_desc->lid_flags |= XFS_LID_DIRTY;
 
 	/*
 	 * Always OR in the bits from the ili_last_fields field.
diff --git a/fs/xfs/xfs_trans_item.c b/fs/xfs/xfs_trans_item.c
deleted file mode 100644
index 55035a7401c..00000000000
--- a/fs/xfs/xfs_trans_item.c
+++ /dev/null
@@ -1,440 +0,0 @@
-/*
- * Copyright (c) 2000-2002,2005 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_types.h"
-#include "xfs_log.h"
-#include "xfs_inum.h"
-#include "xfs_trans.h"
-#include "xfs_trans_priv.h"
-/* XXX: from here down needed until struct xfs_trans has its own ailp */
-#include "xfs_bit.h"
-#include "xfs_buf_item.h"
-#include "xfs_sb.h"
-#include "xfs_ag.h"
-#include "xfs_dir2.h"
-#include "xfs_mount.h"
-
-STATIC int	xfs_trans_unlock_chunk(xfs_log_item_chunk_t *,
-					int, int, xfs_lsn_t);
-
-/*
- * This is called to add the given log item to the transaction's
- * list of log items.  It must find a free log item descriptor
- * or allocate a new one and add the item to that descriptor.
- * The function returns a pointer to item descriptor used to point
- * to the new item.  The log item will now point to its new descriptor
- * with its li_desc field.
- */