svn commit: r193952 - head/sys/nfsclient

[Rick Macklem]

Author: rmacklem
Date: Wed Jun 10 21:03:57 2009
New Revision: 193952
URL: http://svn.freebsd.org/changeset/base/193952

Log:
  Add a test for VI_DOOMED just after nfs_upgrade_vnlock() in
  nfs_bioread_check_cons(). This is required since it is possible
  for the vnode to be vgonel()'d while in nfs_upgrade_vnlock() when
  a forced dismount is in progress. Also, move the check for VI_DOOMED
  in nfs_vinvalbuf() down to after nfs_upgrade_vnlock() and replace the
  out of date comment for it.
  
  Submitted by:	jhb
  Tested by:	pho
  Approved by:	kib (mentor)
  MFC after:	1 month

Modified:
  head/sys/nfsclient/nfs_bio.c

Modified: head/sys/nfsclient/nfs_bio.c
==============================================================================
--- head/sys/nfsclient/nfs_bio.c	Wed Jun 10 20:59:32 2009	(r193951)
+++ head/sys/nfsclient/nfs_bio.c	Wed Jun 10 21:03:57 2009	(r193952)
@@ -389,6 +389,11 @@ nfs_bioread_check_cons(struct vnode *vp,
 	 * But for now, this suffices.
 	 */
 	old_lock = nfs_upgrade_vnlock(vp);
+	if (vp->v_iflag & VI_DOOMED) {
+		nfs_downgrade_vnlock(vp, old_lock);
+		return (EBADF);
+	}
+		
 	mtx_lock(&np->n_mtx);
 	if (np->n_flag & NMODIFIED) {
 		mtx_unlock(&np->n_mtx);
@@ -1289,14 +1294,6 @@ nfs_vinvalbuf(struct vnode *vp, int flag
 
 	ASSERT_VOP_LOCKED(vp, "nfs_vinvalbuf");
 
-	/*
-	 * XXX This check stops us from needlessly doing a vinvalbuf when
-	 * being called through vclean().  It is not clear that this is
-	 * unsafe.
-	 */
-	if (vp->v_iflag & VI_DOOMED)
-		return (0);
-
 	if ((nmp->nm_flag & NFSMNT_INT) == 0)
 		intrflg = 0;
 	if (intrflg) {
@@ -1308,6 +1305,16 @@ nfs_vinvalbuf(struct vnode *vp, int flag
 	}
 
 	old_lock = nfs_upgrade_vnlock(vp);
+	if (vp->v_iflag & VI_DOOMED) {
+		/*
+		 * Since vgonel() uses the generic vinvalbuf() to flush
+		 * dirty buffers and it does not call this function, it
+		 * is safe to just return OK when VI_DOOMED is set.
+		 */
+		nfs_downgrade_vnlock(vp, old_lock);
+		return (0);
+	}
+
 	/*
 	 * Now, flush as required.
 	 */