Merge branch 'for-linus' of git://oss.sgi.com/xfs/xfs
* 'for-linus' of git://oss.sgi.com/xfs/xfs:
xfs: fix race condition in AIL push trigger
xfs: make AIL target updates and compares 32bit safe.
xfs: always push the AIL to the target
xfs: exit AIL push work correctly when AIL is empty
xfs: ensure reclaim cursor is reset correctly at end of AG
diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c
index e4f9c1b..3e898a4 100644
--- a/fs/xfs/linux-2.6/xfs_sync.c
+++ b/fs/xfs/linux-2.6/xfs_sync.c
@@ -926,6 +926,7 @@
XFS_LOOKUP_BATCH,
XFS_ICI_RECLAIM_TAG);
if (!nr_found) {
+ done = 1;
rcu_read_unlock();
break;
}
diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c
index acdb92f..5fc2380 100644
--- a/fs/xfs/xfs_trans_ail.c
+++ b/fs/xfs/xfs_trans_ail.c
@@ -346,20 +346,23 @@
*/
STATIC void
xfs_ail_worker(
- struct work_struct *work)
+ struct work_struct *work)
{
- struct xfs_ail *ailp = container_of(to_delayed_work(work),
+ struct xfs_ail *ailp = container_of(to_delayed_work(work),
struct xfs_ail, xa_work);
- long tout;
- xfs_lsn_t target = ailp->xa_target;
- xfs_lsn_t lsn;
- xfs_log_item_t *lip;
- int flush_log, count, stuck;
- xfs_mount_t *mp = ailp->xa_mount;
+ xfs_mount_t *mp = ailp->xa_mount;
struct xfs_ail_cursor *cur = &ailp->xa_cursors;
- int push_xfsbufd = 0;
+ xfs_log_item_t *lip;
+ xfs_lsn_t lsn;
+ xfs_lsn_t target;
+ long tout = 10;
+ int flush_log = 0;
+ int stuck = 0;
+ int count = 0;
+ int push_xfsbufd = 0;
spin_lock(&ailp->xa_lock);
+ target = ailp->xa_target;
xfs_trans_ail_cursor_init(ailp, cur);
lip = xfs_trans_ail_cursor_first(ailp, cur, ailp->xa_last_pushed_lsn);
if (!lip || XFS_FORCED_SHUTDOWN(mp)) {
@@ -368,8 +371,7 @@
*/
xfs_trans_ail_cursor_done(ailp, cur);
spin_unlock(&ailp->xa_lock);
- ailp->xa_last_pushed_lsn = 0;
- return;
+ goto out_done;
}
XFS_STATS_INC(xs_push_ail);
@@ -386,8 +388,7 @@
* lots of contention on the AIL lists.
*/
lsn = lip->li_lsn;
- flush_log = stuck = count = 0;
- while ((XFS_LSN_CMP(lip->li_lsn, target) < 0)) {
+ while ((XFS_LSN_CMP(lip->li_lsn, target) <= 0)) {
int lock_result;
/*
* If we can lock the item without sleeping, unlock the AIL
@@ -480,21 +481,25 @@
}
/* assume we have more work to do in a short while */
- tout = 10;
+out_done:
if (!count) {
/* We're past our target or empty, so idle */
ailp->xa_last_pushed_lsn = 0;
/*
- * Check for an updated push target before clearing the
- * XFS_AIL_PUSHING_BIT. If the target changed, we've got more
- * work to do. Wait a bit longer before starting that work.
+ * We clear the XFS_AIL_PUSHING_BIT first before checking
+ * whether the target has changed. If the target has changed,
+ * this pushes the requeue race directly onto the result of the
+ * atomic test/set bit, so we are guaranteed that either the
+ * the pusher that changed the target or ourselves will requeue
+ * the work (but not both).
*/
+ clear_bit(XFS_AIL_PUSHING_BIT, &ailp->xa_flags);
smp_rmb();
- if (ailp->xa_target == target) {
- clear_bit(XFS_AIL_PUSHING_BIT, &ailp->xa_flags);
+ if (XFS_LSN_CMP(ailp->xa_target, target) == 0 ||
+ test_and_set_bit(XFS_AIL_PUSHING_BIT, &ailp->xa_flags))
return;
- }
+
tout = 50;
} else if (XFS_LSN_CMP(lsn, target) >= 0) {
/*
@@ -553,7 +558,7 @@
* the XFS_AIL_PUSHING_BIT.
*/
smp_wmb();
- ailp->xa_target = threshold_lsn;
+ xfs_trans_ail_copy_lsn(ailp, &ailp->xa_target, &threshold_lsn);
if (!test_and_set_bit(XFS_AIL_PUSHING_BIT, &ailp->xa_flags))
queue_delayed_work(xfs_syncd_wq, &ailp->xa_work, 0);
}