Merge branch 'linus' into sched/locking

Merge reason: Pick up this upstream commit:

  6631e635c65d: block: don't flush plugged IO on forced preemtion scheduling

As it modifies the scheduler and we'll queue up dependent patches.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 27 insertions, 11 deletions

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 25efa9b8a60..b612ce4520a 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -761,7 +761,7 @@ xfs_log_need_covered(xfs_mount_t *mp)
 		break;
 	case XLOG_STATE_COVER_NEED:
 	case XLOG_STATE_COVER_NEED2:
-		if (!xfs_trans_ail_tail(log->l_ailp) &&
+		if (!xfs_ail_min_lsn(log->l_ailp) &&
 		    xlog_iclogs_empty(log)) {
 			if (log->l_covered_state == XLOG_STATE_COVER_NEED)
 				log->l_covered_state = XLOG_STATE_COVER_DONE;
@@ -801,7 +801,7 @@ xlog_assign_tail_lsn(
 	xfs_lsn_t		tail_lsn;
 	struct log		*log = mp->m_log;
 
-	tail_lsn = xfs_trans_ail_tail(mp->m_ail);
+	tail_lsn = xfs_ail_min_lsn(mp->m_ail);
 	if (!tail_lsn)
 		tail_lsn = atomic64_read(&log->l_last_sync_lsn);
 
@@ -1239,7 +1239,7 @@ xlog_grant_push_ail(
 	 * the filesystem is shutting down.
 	 */
 	if (!XLOG_FORCED_SHUTDOWN(log))
-		xfs_trans_ail_push(log->l_ailp, threshold_lsn);
+		xfs_ail_push(log->l_ailp, threshold_lsn);
 }
 
 /*
@@ -3407,6 +3407,17 @@ xlog_verify_dest_ptr(
 		xfs_emerg(log->l_mp, "%s: invalid ptr", __func__);
 }
 
+/*
+ * Check to make sure the grant write head didn't just over lap the tail.  If
+ * the cycles are the same, we can't be overlapping.  Otherwise, make sure that
+ * the cycles differ by exactly one and check the byte count.
+ *
+ * This check is run unlocked, so can give false positives. Rather than assert
+ * on failures, use a warn-once flag and a panic tag to allow the admin to
+ * determine if they want to panic the machine when such an error occurs. For
+ * debug kernels this will have the same effect as using an assert but, unlinke
+ * an assert, it can be turned off at runtime.
+ */
 STATIC void
 xlog_verify_grant_tail(
 	struct log	*log)
@@ -3414,17 +3425,22 @@ xlog_verify_grant_tail(
 	int		tail_cycle, tail_blocks;
 	int		cycle, space;
 
-	/*
-	 * Check to make sure the grant write head didn't just over lap the
-	 * tail.  If the cycles are the same, we can't be overlapping.
-	 * Otherwise, make sure that the cycles differ by exactly one and
-	 * check the byte count.
-	 */
 	xlog_crack_grant_head(&log->l_grant_write_head, &cycle, &space);
 	xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_blocks);
 	if (tail_cycle != cycle) {
-		ASSERT(cycle - 1 == tail_cycle);
-		ASSERT(space <= BBTOB(tail_blocks));
+		if (cycle - 1 != tail_cycle &&
+		    !(log->l_flags & XLOG_TAIL_WARN)) {
+			xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
+				"%s: cycle - 1 != tail_cycle", __func__);
+			log->l_flags |= XLOG_TAIL_WARN;
+		}
+
+		if (space > BBTOB(tail_blocks) &&
+		    !(log->l_flags & XLOG_TAIL_WARN)) {
+			xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
+				"%s: space > BBTOB(tail_blocks)", __func__);
+			log->l_flags |= XLOG_TAIL_WARN;
+		}
 	}
 }