Moved, renamed, and deleted files

The original directory structure was scattered and unorganized.
Changes are basically to make it look like kernel structure.

1 files changed, 790 insertions, 0 deletions

diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c
new file mode 100644
index 00000000..1dead07f
--- /dev/null
+++ b/fs/xfs/xfs_trans_ail.c
@@ -0,0 +1,790 @@
+/*
+ * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
+ * Copyright (c) 2008 Dave Chinner
+ * 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_sb.h"
+#include "xfs_ag.h"
+#include "xfs_mount.h"
+#include "xfs_trans_priv.h"
+#include "xfs_trace.h"
+#include "xfs_error.h"
+
+#ifdef DEBUG
+/*
+ * Check that the list is sorted as it should be.
+ */
+STATIC void
+xfs_ail_check(
+	struct xfs_ail	*ailp,
+	xfs_log_item_t	*lip)
+{
+	xfs_log_item_t	*prev_lip;
+
+	if (list_empty(&ailp->xa_ail))
+		return;
+
+	/*
+	 * Check the next and previous entries are valid.
+	 */
+	ASSERT((lip->li_flags & XFS_LI_IN_AIL) != 0);
+	prev_lip = list_entry(lip->li_ail.prev, xfs_log_item_t, li_ail);
+	if (&prev_lip->li_ail != &ailp->xa_ail)
+		ASSERT(XFS_LSN_CMP(prev_lip->li_lsn, lip->li_lsn) <= 0);
+
+	prev_lip = list_entry(lip->li_ail.next, xfs_log_item_t, li_ail);
+	if (&prev_lip->li_ail != &ailp->xa_ail)
+		ASSERT(XFS_LSN_CMP(prev_lip->li_lsn, lip->li_lsn) >= 0);
+
+
+#ifdef XFS_TRANS_DEBUG
+	/*
+	 * Walk the list checking lsn ordering, and that every entry has the
+	 * XFS_LI_IN_AIL flag set. This is really expensive, so only do it
+	 * when specifically debugging the transaction subsystem.
+	 */
+	prev_lip = list_entry(&ailp->xa_ail, xfs_log_item_t, li_ail);
+	list_for_each_entry(lip, &ailp->xa_ail, li_ail) {
+		if (&prev_lip->li_ail != &ailp->xa_ail)
+			ASSERT(XFS_LSN_CMP(prev_lip->li_lsn, lip->li_lsn) <= 0);
+		ASSERT((lip->li_flags & XFS_LI_IN_AIL) != 0);
+		prev_lip = lip;
+	}
+#endif /* XFS_TRANS_DEBUG */
+}
+#else /* !DEBUG */
+#define	xfs_ail_check(a,l)
+#endif /* DEBUG */
+
+/*
+ * Return a pointer to the first item in the AIL.  If the AIL is empty, then
+ * return NULL.
+ */
+static xfs_log_item_t *
+xfs_ail_min(
+	struct xfs_ail  *ailp)
+{
+	if (list_empty(&ailp->xa_ail))
+		return NULL;
+
+	return list_first_entry(&ailp->xa_ail, xfs_log_item_t, li_ail);
+}
+
+ /*
+ * Return a pointer to the last item in the AIL.  If the AIL is empty, then
+ * return NULL.
+ */
+static xfs_log_item_t *
+xfs_ail_max(
+	struct xfs_ail  *ailp)
+{
+	if (list_empty(&ailp->xa_ail))
+		return NULL;
+
+	return list_entry(ailp->xa_ail.prev, xfs_log_item_t, li_ail);
+}
+
+/*
+ * Return a pointer to the item which follows the given item in the AIL.  If
+ * the given item is the last item in the list, then return NULL.
+ */
+static xfs_log_item_t *
+xfs_ail_next(
+	struct xfs_ail  *ailp,
+	xfs_log_item_t  *lip)
+{
+	if (lip->li_ail.next == &ailp->xa_ail)
+		return NULL;
+
+	return list_first_entry(&lip->li_ail, xfs_log_item_t, li_ail);
+}
+
+/*
+ * This is called by the log manager code to determine the LSN of the tail of
+ * the log.  This is exactly the LSN of the first item in the AIL.  If the AIL
+ * is empty, then this function returns 0.
+ *
+ * We need the AIL lock in order to get a coherent read of the lsn of the last
+ * item in the AIL.
+ */
+xfs_lsn_t
+xfs_ail_min_lsn(
+	struct xfs_ail	*ailp)
+{
+	xfs_lsn_t	lsn = 0;
+	xfs_log_item_t	*lip;
+
+	spin_lock(&ailp->xa_lock);
+	lip = xfs_ail_min(ailp);
+	if (lip)
+		lsn = lip->li_lsn;
+	spin_unlock(&ailp->xa_lock);
+
+	return lsn;
+}
+
+/*
+ * Return the maximum lsn held in the AIL, or zero if the AIL is empty.
+ */
+static xfs_lsn_t
+xfs_ail_max_lsn(
+	struct xfs_ail  *ailp)
+{
+	xfs_lsn_t       lsn = 0;
+	xfs_log_item_t  *lip;
+
+	spin_lock(&ailp->xa_lock);
+	lip = xfs_ail_max(ailp);
+	if (lip)
+		lsn = lip->li_lsn;
+	spin_unlock(&ailp->xa_lock);
+
+	return lsn;
+}
+
+/*
+ * The cursor keeps track of where our current traversal is up to by tracking
+ * the next item in the list for us. However, for this to be safe, removing an
+ * object from the AIL needs to invalidate any cursor that points to it. hence
+ * the traversal cursor needs to be linked to the struct xfs_ail so that
+ * deletion can search all the active cursors for invalidation.
+ */
+STATIC void
+xfs_trans_ail_cursor_init(
+	struct xfs_ail		*ailp,
+	struct xfs_ail_cursor	*cur)
+{
+	cur->item = NULL;
+	list_add_tail(&cur->list, &ailp->xa_cursors);
+}
+
+/*
+ * Get the next item in the traversal and advance the cursor.  If the cursor
+ * was invalidated (indicated by a lip of 1), restart the traversal.
+ */
+struct xfs_log_item *
+xfs_trans_ail_cursor_next(
+	struct xfs_ail		*ailp,
+	struct xfs_ail_cursor	*cur)
+{
+	struct xfs_log_item	*lip = cur->item;
+
+	if ((__psint_t)lip & 1)
+		lip = xfs_ail_min(ailp);
+	if (lip)
+		cur->item = xfs_ail_next(ailp, lip);
+	return lip;
+}
+
+/*
+ * When the traversal is complete, we need to remove the cursor from the list
+ * of traversing cursors.
+ */
+void
+xfs_trans_ail_cursor_done(
+	struct xfs_ail		*ailp,
+	struct xfs_ail_cursor	*cur)
+{
+	cur->item = NULL;
+	list_del_init(&cur->list);
+}
+
+/*
+ * Invalidate any cursor that is pointing to this item. This is called when an
+ * item is removed from the AIL. Any cursor pointing to this object is now
+ * invalid and the traversal needs to be terminated so it doesn't reference a
+ * freed object. We set the low bit of the cursor item pointer so we can
+ * distinguish between an invalidation and the end of the list when getting the
+ * next item from the cursor.
+ */
+STATIC void
+xfs_trans_ail_cursor_clear(
+	struct xfs_ail		*ailp,
+	struct xfs_log_item	*lip)
+{
+	struct xfs_ail_cursor	*cur;
+
+	list_for_each_entry(cur, &ailp->xa_cursors, list) {
+		if (cur->item == lip)
+			cur->item = (struct xfs_log_item *)
+					((__psint_t)cur->item | 1);
+	}
+}
+
+/*
+ * Find the first item in the AIL with the given @lsn by searching in ascending
+ * LSN order and initialise the cursor to point to the next item for a
+ * ascending traversal.  Pass a @lsn of zero to initialise the cursor to the
+ * first item in the AIL. Returns NULL if the list is empty.
+ */
+xfs_log_item_t *
+xfs_trans_ail_cursor_first(
+	struct xfs_ail		*ailp,
+	struct xfs_ail_cursor	*cur,
+	xfs_lsn_t		lsn)
+{
+	xfs_log_item_t		*lip;
+
+	xfs_trans_ail_cursor_init(ailp, cur);
+
+	if (lsn == 0) {
+		lip = xfs_ail_min(ailp);
+		goto out;
+	}
+
+	list_for_each_entry(lip, &ailp->xa_ail, li_ail) {
+		if (XFS_LSN_CMP(lip->li_lsn, lsn) >= 0)
+			goto out;
+	}
+	return NULL;
+
+out:
+	if (lip)
+		cur->item = xfs_ail_next(ailp, lip);
+	return lip;
+}
+
+static struct xfs_log_item *
+__xfs_trans_ail_cursor_last(
+	struct xfs_ail		*ailp,
+	xfs_lsn_t		lsn)
+{
+	xfs_log_item_t		*lip;
+
+	list_for_each_entry_reverse(lip, &ailp->xa_ail, li_ail) {
+		if (XFS_LSN_CMP(lip->li_lsn, lsn) <= 0)
+			return lip;
+	}
+	return NULL;
+}
+
+/*
+ * Find the last item in the AIL with the given @lsn by searching in descending
+ * LSN order and initialise the cursor to point to that item.  If there is no
+ * item with the value of @lsn, then it sets the cursor to the last item with an
+ * LSN lower than @lsn.  Returns NULL if the list is empty.
+ */
+struct xfs_log_item *
+xfs_trans_ail_cursor_last(
+	struct xfs_ail		*ailp,
+	struct xfs_ail_cursor	*cur,
+	xfs_lsn_t		lsn)
+{
+	xfs_trans_ail_cursor_init(ailp, cur);
+	cur->item = __xfs_trans_ail_cursor_last(ailp, lsn);
+	return cur->item;
+}
+
+/*
+ * Splice the log item list into the AIL at the given LSN. We splice to the
+ * tail of the given LSN to maintain insert order for push traversals. The
+ * cursor is optional, allowing repeated updates to the same LSN to avoid
+ * repeated traversals.  This should not be called with an empty list.
+ */
+static void
+xfs_ail_splice(
+	struct xfs_ail		*ailp,
+	struct xfs_ail_cursor	*cur,
+	struct list_head	*list,
+	xfs_lsn_t		lsn)
+{
+	struct xfs_log_item	*lip;
+
+	ASSERT(!list_empty(list));
+
+	/*
+	 * Use the cursor to determine the insertion point if one is
+	 * provided.  If not, or if the one we got is not valid,
+	 * find the place in the AIL where the items belong.
+	 */
+	lip = cur ? cur->item : NULL;
+	if (!lip || (__psint_t) lip & 1)
+		lip = __xfs_trans_ail_cursor_last(ailp, lsn);
+
+	/*
+	 * If a cursor is provided, we know we're processing the AIL
+	 * in lsn order, and future items to be spliced in will
+	 * follow the last one being inserted now.  Update the
+	 * cursor to point to that last item, now while we have a
+	 * reliable pointer to it.
+	 */
+	if (cur)
+		cur->item = list_entry(list->prev, struct xfs_log_item, li_ail);
+
+	/*
+	 * Finally perform the splice.  Unless the AIL was empty,
+	 * lip points to the item in the AIL _after_ which the new
+	 * items should go.  If lip is null the AIL was empty, so
+	 * the new items go at the head of the AIL.
+	 */
+	if (lip)
+		list_splice(list, &lip->li_ail);
+	else
+		list_splice(list, &ailp->xa_ail);
+}
+
+/*
+ * Delete the given item from the AIL.  Return a pointer to the item.
+ */
+static void
+xfs_ail_delete(
+	struct xfs_ail  *ailp,
+	xfs_log_item_t  *lip)
+{
+	xfs_ail_check(ailp, lip);
+	list_del(&lip->li_ail);
+	xfs_trans_ail_cursor_clear(ailp, lip);
+}
+
+static long
+xfsaild_push(
+	struct xfs_ail		*ailp)
+{
+	xfs_mount_t		*mp = ailp->xa_mount;
+	struct xfs_ail_cursor	cur;
+	xfs_log_item_t		*lip;
+	xfs_lsn_t		lsn;
+	xfs_lsn_t		target;
+	long			tout = 10;
+	int			stuck = 0;
+	int			count = 0;
+	int			push_xfsbufd = 0;
+
+	/*
+	 * If last time we ran we encountered pinned items, force the log first
+	 * and wait for it before pushing again.
+	 */
+	spin_lock(&ailp->xa_lock);
+	if (ailp->xa_last_pushed_lsn == 0 && ailp->xa_log_flush &&
+	    !list_empty(&ailp->xa_ail)) {
+		ailp->xa_log_flush = 0;
+		spin_unlock(&ailp->xa_lock);
+		XFS_STATS_INC(xs_push_ail_flush);
+		xfs_log_force(mp, XFS_LOG_SYNC);
+		spin_lock(&ailp->xa_lock);
+	}
+
+	target = ailp->xa_target;
+	lip = xfs_trans_ail_cursor_first(ailp, &cur, ailp->xa_last_pushed_lsn);
+	if (!lip || XFS_FORCED_SHUTDOWN(mp)) {
+		/*
+		 * AIL is empty or our push has reached the end.
+		 */
+		xfs_trans_ail_cursor_done(ailp, &cur);
+		spin_unlock(&ailp->xa_lock);
+		goto out_done;
+	}
+
+	XFS_STATS_INC(xs_push_ail);
+
+	/*
+	 * While the item we are looking at is below the given threshold
+	 * try to flush it out. We'd like not to stop until we've at least
+	 * tried to push on everything in the AIL with an LSN less than
+	 * the given threshold.
+	 *
+	 * However, we will stop after a certain number of pushes and wait
+	 * for a reduced timeout to fire before pushing further. This
+	 * prevents use from spinning when we can't do anything or there is
+	 * lots of contention on the AIL lists.
+	 */
+	lsn = lip->li_lsn;
+	while ((XFS_LSN_CMP(lip->li_lsn, target) <= 0)) {
+		int	lock_result;
+		/*
+		 * If we can lock the item without sleeping, unlock the AIL
+		 * lock and flush the item.  Then re-grab the AIL lock so we
+		 * can look for the next item on the AIL. List changes are
+		 * handled by the AIL lookup functions internally
+		 *
+		 * If we can't lock the item, either its holder will flush it
+		 * or it is already being flushed or it is being relogged.  In
+		 * any of these case it is being taken care of and we can just
+		 * skip to the next item in the list.
+		 */
+		lock_result = IOP_TRYLOCK(lip);
+		spin_unlock(&ailp->xa_lock);
+		switch (lock_result) {
+		case XFS_ITEM_SUCCESS:
+			XFS_STATS_INC(xs_push_ail_success);
+			trace_xfs_ail_push(lip);
+
+			IOP_PUSH(lip);
+			ailp->xa_last_pushed_lsn = lsn;
+			break;
+
+		case XFS_ITEM_PUSHBUF:
+			XFS_STATS_INC(xs_push_ail_pushbuf);
+			trace_xfs_ail_pushbuf(lip);
+
+			if (!IOP_PUSHBUF(lip)) {
+				trace_xfs_ail_pushbuf_pinned(lip);
+				stuck++;
+				ailp->xa_log_flush++;
+			} else {
+				ailp->xa_last_pushed_lsn = lsn;
+			}
+			push_xfsbufd = 1;
+			break;
+
+		case XFS_ITEM_PINNED:
+			XFS_STATS_INC(xs_push_ail_pinned);
+			trace_xfs_ail_pinned(lip);
+
+			stuck++;
+			ailp->xa_log_flush++;
+			break;
+
+		case XFS_ITEM_LOCKED:
+			XFS_STATS_INC(xs_push_ail_locked);
+			trace_xfs_ail_locked(lip);
+			stuck++;
+			break;
+
+		default:
+			ASSERT(0);
+			break;
+		}
+
+		spin_lock(&ailp->xa_lock);
+		/* should we bother continuing? */
+		if (XFS_FORCED_SHUTDOWN(mp))
+			break;
+		ASSERT(mp->m_log);
+
+		count++;
+
+		/*
+		 * Are there too many items we can't do anything with?
+		 * If we we are skipping too many items because we can't flush
+		 * them or they are already being flushed, we back off and
+		 * given them time to complete whatever operation is being
+		 * done. i.e. remove pressure from the AIL while we can't make
+		 * progress so traversals don't slow down further inserts and
+		 * removals to/from the AIL.
+		 *
+		 * The value of 100 is an arbitrary magic number based on
+		 * observation.
+		 */
+		if (stuck > 100)
+			break;
+
+		lip = xfs_trans_ail_cursor_next(ailp, &cur);
+		if (lip == NULL)
+			break;
+		lsn = lip->li_lsn;
+	}
+	xfs_trans_ail_cursor_done(ailp, &cur);
+	spin_unlock(&ailp->xa_lock);
+
+	if (push_xfsbufd) {
+		/* we've got delayed write buffers to flush */
+		wake_up_process(mp->m_ddev_targp->bt_task);
+	}
+
+	/* assume we have more work to do in a short while */
+out_done:
+	if (!count) {
+		/* We're past our target or empty, so idle */
+		ailp->xa_last_pushed_lsn = 0;
+		ailp->xa_log_flush = 0;
+
+		tout = 50;
+	} else if (XFS_LSN_CMP(lsn, target) >= 0) {
+		/*
+		 * We reached the target so wait a bit longer for I/O to
+		 * complete and remove pushed items from the AIL before we
+		 * start the next scan from the start of the AIL.
+		 */
+		tout = 50;
+		ailp->xa_last_pushed_lsn = 0;
+	} else if ((stuck * 100) / count > 90) {
+		/*
+		 * Either there is a lot of contention on the AIL or we
+		 * are stuck due to operations in progress. "Stuck" in this
+		 * case is defined as >90% of the items we tried to push
+		 * were stuck.
+		 *
+		 * Backoff a bit more to allow some I/O to complete before
+		 * restarting from the start of the AIL. This prevents us
+		 * from spinning on the same items, and if they are pinned will
+		 * all the restart to issue a log force to unpin the stuck
+		 * items.
+		 */
+		tout = 20;
+		ailp->xa_last_pushed_lsn = 0;
+	}
+
+	return tout;
+}
+
+static int
+xfsaild(
+	void		*data)
+{
+	struct xfs_ail	*ailp = data;
+	long		tout = 0;	/* milliseconds */
+
+	while (!kthread_should_stop()) {
+		if (tout && tout <= 20)
+			__set_current_state(TASK_KILLABLE);
+		else
+			__set_current_state(TASK_INTERRUPTIBLE);
+		schedule_timeout(tout ?
+				 msecs_to_jiffies(tout) : MAX_SCHEDULE_TIMEOUT);
+
+		try_to_freeze();
+
+		tout = xfsaild_push(ailp);
+	}
+
+	return 0;
+}
+
+/*
+ * This routine is called to move the tail of the AIL forward.  It does this by
+ * trying to flush items in the AIL whose lsns are below the given
+ * threshold_lsn.
+ *
+ * The push is run asynchronously in a workqueue, which means the caller needs
+ * to handle waiting on the async flush for space to become available.
+ * We don't want to interrupt any push that is in progress, hence we only queue
+ * work if we set the pushing bit approriately.
+ *
+ * We do this unlocked - we only need to know whether there is anything in the
+ * AIL at the time we are called. We don't need to access the contents of
+ * any of the objects, so the lock is not needed.
+ */
+void
+xfs_ail_push(
+	struct xfs_ail	*ailp,
+	xfs_lsn_t	threshold_lsn)
+{
+	xfs_log_item_t	*lip;
+
+	lip = xfs_ail_min(ailp);
+	if (!lip || XFS_FORCED_SHUTDOWN(ailp->xa_mount) ||
+	    XFS_LSN_CMP(threshold_lsn, ailp->xa_target) <= 0)
+		return;
+
+	/*
+	 * Ensure that the new target is noticed in push code before it clears
+	 * the XFS_AIL_PUSHING_BIT.
+	 */
+	smp_wmb();
+	xfs_trans_ail_copy_lsn(ailp, &ailp->xa_target, &threshold_lsn);
+	smp_wmb();
+
+	wake_up_process(ailp->xa_task);
+}
+
+/*
+ * Push out all items in the AIL immediately
+ */
+void
+xfs_ail_push_all(
+	struct xfs_ail  *ailp)
+{
+	xfs_lsn_t       threshold_lsn = xfs_ail_max_lsn(ailp);
+
+	if (threshold_lsn)
+		xfs_ail_push(ailp, threshold_lsn);
+}
+
+/*
+ * xfs_trans_ail_update - bulk AIL insertion operation.
+ *
+ * @xfs_trans_ail_update takes an array of log items that all need to be
+ * positioned at the same LSN in the AIL. If an item is not in the AIL, it will
+ * be added.  Otherwise, it will be repositioned  by removing it and re-adding
+ * it to the AIL. If we move the first item in the AIL, update the log tail to
+ * match the new minimum LSN in the AIL.
+ *
+ * This function takes the AIL lock once to execute the update operations on
+ * all the items in the array, and as such should not be called with the AIL
+ * lock held. As a result, once we have the AIL lock, we need to check each log
+ * item LSN to confirm it needs to be moved forward in the AIL.
+ *
+ * To optimise the insert operation, we delete all the items from the AIL in
+ * the first pass, moving them into a temporary list, then splice the temporary
+ * list into the correct position in the AIL. This avoids needing to do an
+ * insert operation on every item.
+ *
+ * This function must be called with the AIL lock held.  The lock is dropped
+ * before returning.
+ */
+void
+xfs_trans_ail_update_bulk(
+	struct xfs_ail		*ailp,
+	struct xfs_ail_cursor	*cur,
+	struct xfs_log_item	**log_items,
+	int			nr_items,
+	xfs_lsn_t		lsn) __releases(ailp->xa_lock)
+{
+	xfs_log_item_t		*mlip;
+	int			mlip_changed = 0;
+	int			i;
+	LIST_HEAD(tmp);
+
+	ASSERT(nr_items > 0);		/* Not required, but true. */
+	mlip = xfs_ail_min(ailp);
+
+	for (i = 0; i < nr_items; i++) {
+		struct xfs_log_item *lip = log_items[i];
+		if (lip->li_flags & XFS_LI_IN_AIL) {
+			/* check if we really need to move the item */
+			if (XFS_LSN_CMP(lsn, lip->li_lsn) <= 0)
+				continue;
+
+			xfs_ail_delete(ailp, lip);
+			if (mlip == lip)
+				mlip_changed = 1;
+		} else {
+			lip->li_flags |= XFS_LI_IN_AIL;
+		}
+		lip->li_lsn = lsn;
+		list_add(&lip->li_ail, &tmp);
+	}
+
+	if (!list_empty(&tmp))
+		xfs_ail_splice(ailp, cur, &tmp, lsn);
+	spin_unlock(&ailp->xa_lock);
+
+	if (mlip_changed && !XFS_FORCED_SHUTDOWN(ailp->xa_mount)) {
+		xlog_assign_tail_lsn(ailp->xa_mount);
+		xfs_log_space_wake(ailp->xa_mount);
+	}
+}
+
+/*
+ * xfs_trans_ail_delete_bulk - remove multiple log items from the AIL
+ *
+ * @xfs_trans_ail_delete_bulk takes an array of log items that all need to
+ * removed from the AIL. The caller is already holding the AIL lock, and done
+ * all the checks necessary to ensure the items passed in via @log_items are
+ * ready for deletion. This includes checking that the items are in the AIL.
+ *
+ * For each log item to be removed, unlink it  from the AIL, clear the IN_AIL
+ * flag from the item and reset the item's lsn to 0. If we remove the first
+ * item in the AIL, update the log tail to match the new minimum LSN in the
+ * AIL.
+ *
+ * This function will not drop the AIL lock until all items are removed from
+ * the AIL to minimise the amount of lock traffic on the AIL. This does not
+ * greatly increase the AIL hold time, but does significantly reduce the amount
+ * of traffic on the lock, especially during IO completion.
+ *
+ * This function must be called with the AIL lock held.  The lock is dropped
+ * before returning.
+ */
+void
+xfs_trans_ail_delete_bulk(
+	struct xfs_ail		*ailp,
+	struct xfs_log_item	**log_items,
+	int			nr_items) __releases(ailp->xa_lock)
+{
+	xfs_log_item_t		*mlip;
+	int			mlip_changed = 0;
+	int			i;
+
+	mlip = xfs_ail_min(ailp);
+
+	for (i = 0; i < nr_items; i++) {
+		struct xfs_log_item *lip = log_items[i];
+		if (!(lip->li_flags & XFS_LI_IN_AIL)) {
+			struct xfs_mount	*mp = ailp->xa_mount;
+
+			spin_unlock(&ailp->xa_lock);
+			if (!XFS_FORCED_SHUTDOWN(mp)) {
+				xfs_alert_tag(mp, XFS_PTAG_AILDELETE,
+		"%s: attempting to delete a log item that is not in the AIL",
+						__func__);
+				xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
+			}
+			return;
+		}
+
+		xfs_ail_delete(ailp, lip);
+		lip->li_flags &= ~XFS_LI_IN_AIL;
+		lip->li_lsn = 0;
+		if (mlip == lip)
+			mlip_changed = 1;
+	}
+	spin_unlock(&ailp->xa_lock);
+
+	if (mlip_changed && !XFS_FORCED_SHUTDOWN(ailp->xa_mount)) {
+		xlog_assign_tail_lsn(ailp->xa_mount);
+		xfs_log_space_wake(ailp->xa_mount);
+	}
+}
+
+/*
+ * The active item list (AIL) is a doubly linked list of log
+ * items sorted by ascending lsn.  The base of the list is
+ * a forw/back pointer pair embedded in the xfs mount structure.
+ * The base is initialized with both pointers pointing to the
+ * base.  This case always needs to be distinguished, because
+ * the base has no lsn to look at.  We almost always insert
+ * at the end of the list, so on inserts we search from the
+ * end of the list to find where the new item belongs.
+ */
+
+/*
+ * Initialize the doubly linked list to point only to itself.
+ */
+int
+xfs_trans_ail_init(
+	xfs_mount_t	*mp)
+{
+	struct xfs_ail	*ailp;
+
+	ailp = kmem_zalloc(sizeof(struct xfs_ail), KM_MAYFAIL);
+	if (!ailp)
+		return ENOMEM;
+
+	ailp->xa_mount = mp;
+	INIT_LIST_HEAD(&ailp->xa_ail);
+	INIT_LIST_HEAD(&ailp->xa_cursors);
+	spin_lock_init(&ailp->xa_lock);
+
+	ailp->xa_task = kthread_run(xfsaild, ailp, "xfsaild/%s",
+			ailp->xa_mount->m_fsname);
+	if (IS_ERR(ailp->xa_task))
+		goto out_free_ailp;
+
+	mp->m_ail = ailp;
+	return 0;
+
+out_free_ailp:
+	kmem_free(ailp);
+	return ENOMEM;
+}
+
+void
+xfs_trans_ail_destroy(
+	xfs_mount_t	*mp)
+{
+	struct xfs_ail	*ailp = mp->m_ail;
+
+	kthread_stop(ailp->xa_task);
+	kmem_free(ailp);
+}