For many years the message "fsync: giving up on dirty" has occationally

appeared on UFS/FFS filesystems. In some cases it was promptly followed
by a panic of "softdep_deallocate_dependencies: dangling deps". This fix
should eliminate both of these occurences.

Submitted by: Andreas Longwitz <longwitz at incore.de>
Reviewed by:  kib
Tested by:    Peter Holm (pho)
PR:           225423
MFC after:    1 week

1 files changed, 17 insertions, 6 deletions

diff --git a/sys/kern/vfs_default.c b/sys/kern/vfs_default.c
index 734c2f2e6011..d09e0d91b96f 100644
--- a/sys/kern/vfs_default.c
+++ b/sys/kern/vfs_default.c
@@ -631,13 +631,21 @@ vop_stdfsync(ap)
 		struct thread *a_td;
 	} */ *ap;
 {
-	struct vnode *vp = ap->a_vp;
-	struct buf *bp;
+	struct vnode *vp;
+	struct buf *bp, *nbp;
 	struct bufobj *bo;
-	struct buf *nbp;
-	int error = 0;
-	int maxretry = 1000;     /* large, arbitrarily chosen */
+	struct mount *mp;
+	int error, maxretry;
 
+	error = 0;
+	maxretry = 10000;     /* large, arbitrarily chosen */
+	vp = ap->a_vp;
+	mp = NULL;
+	if (vp->v_type == VCHR) {
+		VI_LOCK(vp);
+		mp = vp->v_rdev->si_mountpt;
+		VI_UNLOCK(vp);
+	}
 	bo = &vp->v_bufobj;
 	BO_LOCK(bo);
 loop1:
@@ -680,6 +688,8 @@ loop2:
 			bremfree(bp);
 			bawrite(bp);
 		}
+		if (maxretry < 1000)
+			pause("dirty", hz < 1000 ? 1 : hz / 1000);
 		BO_LOCK(bo);
 		goto loop2;
 	}
@@ -701,7 +711,8 @@ loop2:
 			TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs)
 				if ((error = bp->b_error) != 0)
 					break;
-			if (error == 0 && --maxretry >= 0)
+			if ((mp != NULL && mp->mnt_secondary_writes > 0) ||
+			    (error == 0 && --maxretry >= 0))
 				goto loop1;
 			error = EAGAIN;
 		}