svn commit: r269562 - stable/10/sys/kern

[Konstantin Belousov]

Author: kib
Date: Tue Aug  5 05:00:22 2014
New Revision: 269562
URL: http://svnweb.freebsd.org/changeset/base/269562

Log:
  MFC r269244:
  Remove one-time use macros which check for the vnode lifecycle.

Modified:
  stable/10/sys/kern/vfs_subr.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/sys/kern/vfs_subr.c
==============================================================================
--- stable/10/sys/kern/vfs_subr.c	Tue Aug  5 02:22:58 2014	(r269561)
+++ stable/10/sys/kern/vfs_subr.c	Tue Aug  5 05:00:22 2014	(r269562)
@@ -275,14 +275,6 @@ static int vnlru_nowhere;
 SYSCTL_INT(_debug, OID_AUTO, vnlru_nowhere, CTLFLAG_RW,
     &vnlru_nowhere, 0, "Number of times the vnlru process ran without success");
 
-/*
- * Macros to control when a vnode is freed and recycled.  All require
- * the vnode interlock.
- */
-#define VCANRECYCLE(vp) (((vp)->v_iflag & VI_FREE) && !(vp)->v_holdcnt)
-#define VSHOULDFREE(vp) (!((vp)->v_iflag & VI_FREE) && !(vp)->v_holdcnt)
-#define VSHOULDBUSY(vp) (((vp)->v_iflag & VI_FREE) && (vp)->v_holdcnt)
-
 /* Shift count for (uintptr_t)vp to initialize vp->v_hash. */
 static int vnsz2log;
 
@@ -849,11 +841,21 @@ vnlru_free(int count)
 			TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_actfreelist);
 			continue;
 		}
-		VNASSERT(VCANRECYCLE(vp), vp,
-		    ("vp inconsistent on freelist"));
+		VNASSERT((vp->v_iflag & VI_FREE) != 0 && vp->v_holdcnt == 0,
+		    vp, ("vp inconsistent on freelist"));
+
+		/*
+		 * The clear of VI_FREE prevents activation of the
+		 * vnode.  There is no sense in putting the vnode on
+		 * the mount point active list, only to remove it
+		 * later during recycling.  Inline the relevant part
+		 * of vholdl(), to avoid triggering assertions or
+		 * activating.
+		 */
 		freevnodes--;
 		vp->v_iflag &= ~VI_FREE;
-		vholdl(vp);
+		vp->v_holdcnt++;
+
 		mtx_unlock(&vnode_free_list_mtx);
 		VI_UNLOCK(vp);
 		vtryrecycle(vp);
@@ -2042,13 +2044,13 @@ v_incr_usecount(struct vnode *vp)
 {
 
 	CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
+	vholdl(vp);
 	vp->v_usecount++;
 	if (vp->v_type == VCHR && vp->v_rdev != NULL) {
 		dev_lock();
 		vp->v_rdev->si_usecount++;
 		dev_unlock();
 	}
-	vholdl(vp);
 }
 
 /*
@@ -2325,11 +2327,18 @@ vholdl(struct vnode *vp)
 	struct mount *mp;
 
 	CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
+#ifdef INVARIANTS
+	/* getnewvnode() calls v_incr_usecount() without holding interlock. */
+	if (vp->v_type != VNON || vp->v_data != NULL) {
+		ASSERT_VI_LOCKED(vp, "vholdl");
+		VNASSERT(vp->v_holdcnt > 0 || (vp->v_iflag & VI_FREE) != 0,
+		    vp, ("vholdl: free vnode is held"));
+	}
+#endif
 	vp->v_holdcnt++;
-	if (!VSHOULDBUSY(vp))
+	if ((vp->v_iflag & VI_FREE) == 0)
 		return;
-	ASSERT_VI_LOCKED(vp, "vholdl");
-	VNASSERT((vp->v_iflag & VI_FREE) != 0, vp, ("vnode not free"));
+	VNASSERT(vp->v_holdcnt == 1, vp, ("vholdl: wrong hold count"));
 	VNASSERT(vp->v_op != NULL, vp, ("vholdl: vnode already reclaimed."));
 	/*
 	 * Remove a vnode from the free list, mark it as in use,
@@ -2390,7 +2399,7 @@ vdropl(struct vnode *vp)
 		    ("vdropl: vnode already reclaimed."));
 		VNASSERT((vp->v_iflag & VI_FREE) == 0, vp,
 		    ("vnode already free"));
-		VNASSERT(VSHOULDFREE(vp), vp,
+		VNASSERT(vp->v_holdcnt == 0, vp,
 		    ("vdropl: freeing when we shouldn't"));
 		active = vp->v_iflag & VI_ACTIVE;
 		vp->v_iflag &= ~VI_ACTIVE;