Protect vn worklist and vn->v_{clean,dirty}blkhd at splbio().

    Get rid of extra LIST_REMOVE()

Reviewed by:	hsu@FreeBSD.ORG (Jeffrey Hsu), mckusick@McKusick.COM
Submitted by:	hsu@FreeBSD.ORG (Jeffrey Hsu), dillon@backplane.com ( Matthew Dillon )

1 files changed, 17 insertions, 9 deletions

diff --git a/sys/kern/vfs_export.c b/sys/kern/vfs_export.c
index 6cf879d..8bc6935 100644
--- a/sys/kern/vfs_export.c
+++ b/sys/kern/vfs_export.c
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)vfs_subr.c	8.31 (Berkeley) 5/26/95
- * $Id: vfs_subr.c,v 1.185 1999/01/29 23:18:49 dillon Exp $
+ * $Id: vfs_subr.c,v 1.186 1999/02/04 18:25:39 dillon Exp $
  */
 
 /*
@@ -881,10 +881,8 @@ brelvp(bp)
 /*
  * Add an item to the syncer work queue.
  */
-void
-vn_syncer_add_to_worklist(vp, delay)
-	struct vnode *vp;
-	int delay;
+static void
+vn_syncer_add_to_worklist(struct vnode *vp, int delay)
 {
 	int s, slot;
 
@@ -928,7 +926,8 @@ sched_sync(void)
 		starttime = time_second;
 
 		/*
-		 * Push files whose dirty time has expired.
+		 * Push files whose dirty time has expired.  Be careful
+		 * of interrupt race on slp queue.
 		 */
 		s = splbio();
 		slp = &syncer_workitem_pending[syncer_delayno];
@@ -941,16 +940,20 @@ sched_sync(void)
 			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
 			(void) VOP_FSYNC(vp, p->p_ucred, MNT_LAZY, p);
 			VOP_UNLOCK(vp, 0, p);
+			s = splbio();
 			if (LIST_FIRST(slp) == vp) {
 				if (TAILQ_EMPTY(&vp->v_dirtyblkhd) &&
 				    vp->v_type != VBLK)
-					panic("sched_sync: fsync failed");
+					panic("sched_sync: fsync failed vp %p tag %d", vp, vp->v_tag);
 				/*
-				 * Move ourselves to the back of the sync list.
+				 * Put us back on the worklist.  The worklist
+				 * routine will remove us from our current
+				 * position and then add us back in at a later
+				 * position.
 				 */
-				LIST_REMOVE(vp, v_synclist);
 				vn_syncer_add_to_worklist(vp, syncdelay);
 			}
+			splx(s);
 		}
 
 		/*
@@ -2841,6 +2844,8 @@ sync_inactive(ap)
 
 /*
  * The syncer vnode is no longer needed and is being decommissioned.
+ *
+ * Modifications to the worklist must be protected at splbio().
  */
 static int
 sync_reclaim(ap)
@@ -2849,12 +2854,15 @@ sync_reclaim(ap)
 	} */ *ap;
 {
 	struct vnode *vp = ap->a_vp;
+	int s;
 
+	s = splbio();
 	vp->v_mount->mnt_syncer = NULL;
 	if (vp->v_flag & VONWORKLST) {
 		LIST_REMOVE(vp, v_synclist);
 		vp->v_flag &= ~VONWORKLST;
 	}
+	splx(s);
 
 	return (0);
 }