From: markj <markj@FreeBSD.org>
Date: Thu, 1 Oct 2015 16:34:53 +0000 (+0000)
Subject: Ensure that vop_stdadvise() does not call getblk() on vnodes that have an
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=49cededc7e35f14e10f5df9a819ef835b4073dfb;p=people%2Fjulieng%2Ffreebsd.git

Ensure that vop_stdadvise() does not call getblk() on vnodes that have an
empty bufobj. Otherwise, vnodes belonging to filesystems that do not use the
buffer cache may trigger assertion failures.

Reported by:	Fabien Keil
---

diff --git a/sys/kern/vfs_default.c b/sys/kern/vfs_default.c
index d0074d3e34ed..6ee094b9144b 100644
--- a/sys/kern/vfs_default.c
+++ b/sys/kern/vfs_default.c
@@ -1077,16 +1077,15 @@ vop_stdadvise(struct vop_advise_args *ap)
 		BO_RLOCK(&vp->v_bufobj);
 		bsize = vp->v_bufobj.bo_bsize;
 		startn = ap->a_start / bsize;
-		if (ap->a_end == OFF_MAX) {
-			endn = -1;
-			bl = &vp->v_bufobj.bo_clean.bv_hd;
-			if (!TAILQ_EMPTY(bl))
-				endn = TAILQ_LAST(bl, buflists)->b_lblkno;
-			bl = &vp->v_bufobj.bo_dirty.bv_hd;
-			if (!TAILQ_EMPTY(bl) &&
-			    endn < TAILQ_LAST(bl, buflists)->b_lblkno)
-				endn = TAILQ_LAST(bl, buflists)->b_lblkno;
-		} else
+		endn = -1;
+		bl = &vp->v_bufobj.bo_clean.bv_hd;
+		if (!TAILQ_EMPTY(bl))
+			endn = TAILQ_LAST(bl, buflists)->b_lblkno;
+		bl = &vp->v_bufobj.bo_dirty.bv_hd;
+		if (!TAILQ_EMPTY(bl) &&
+		    endn < TAILQ_LAST(bl, buflists)->b_lblkno)
+			endn = TAILQ_LAST(bl, buflists)->b_lblkno;
+		if (ap->a_end != OFF_MAX && endn != -1)
 			endn = ap->a_end / bsize;
 		BO_RUNLOCK(&vp->v_bufobj);
 		/*