Fixed null pointer panics which I introduced in rev.1.86. Vnodes

may be revoked, so vnop routines must be careful about accessing
the vnode if they may have blocked.

Fixed marking for update after successfully reading or writing 0
bytes.  In this case, POSIX.1 specifies marking if and only if the
requested count is nonzero, but rev.1.86 never marked.

1 files changed, 19 insertions, 7 deletions

diff --git a/sys/ufs/ufs/ufs_vnops.c b/sys/ufs/ufs/ufs_vnops.c
index 47578d0ee2a6..a0f0a53e413a 100644
--- a/sys/ufs/ufs/ufs_vnops.c
+++ b/sys/ufs/ufs/ufs_vnops.c
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)ufs_vnops.c	8.27 (Berkeley) 5/27/95
- * $Id: ufs_vnops.c,v 1.101 1998/12/09 02:06:27 eivind Exp $
+ * $Id: ufs_vnops.c,v 1.102 1998/12/20 12:36:01 dfr Exp $
  */
 
 #include "opt_quota.h"
@@ -1810,13 +1810,19 @@ ufsspec_read(ap)
 	} */ *ap;
 {
 	int error, resid;
+	struct inode *ip;
 	struct uio *uio;
 
 	uio = ap->a_uio;
 	resid = uio->uio_resid;
 	error = VOCALL(spec_vnodeop_p, VOFFSET(vop_read), ap);
-	if (uio->uio_resid != resid)
-		VTOI(ap->a_vp)->i_flag |= IN_ACCESS;
+	/*
+	 * The inode may have been revoked during the call, so it must not
+	 * be accessed blindly here or in the other wrapper functions.
+	 */
+	ip = VTOI(ap->a_vp);
+	if (ip != NULL && (uio->uio_resid != resid || error == 0 && resid != 0))
+		ip->i_flag |= IN_ACCESS;
 	return (error);
 }
 
@@ -1833,12 +1839,14 @@ ufsspec_write(ap)
 	} */ *ap;
 {
 	int error, resid;
+	struct inode *ip;
 	struct uio *uio;
 
 	uio = ap->a_uio;
 	resid = uio->uio_resid;
 	error = VOCALL(spec_vnodeop_p, VOFFSET(vop_write), ap);
-	if (uio->uio_resid != resid)
+	ip = VTOI(ap->a_vp);
+	if (ip != NULL && (uio->uio_resid != resid || error == 0 && resid != 0))
 		VTOI(ap->a_vp)->i_flag |= IN_CHANGE | IN_UPDATE;
 	return (error);
 }
@@ -1879,13 +1887,15 @@ ufsfifo_read(ap)
 	} */ *ap;
 {
 	int error, resid;
+	struct inode *ip;
 	struct uio *uio;
 
 	uio = ap->a_uio;
 	resid = uio->uio_resid;
 	error = VOCALL(fifo_vnodeop_p, VOFFSET(vop_read), ap);
-	if (uio->uio_resid != resid &&
-	    (ap->a_vp->v_mount->mnt_flag & MNT_NOATIME) == 0)
+	ip = VTOI(ap->a_vp);
+	if ((ap->a_vp->v_mount->mnt_flag & MNT_NOATIME) == 0 && ip != NULL &&
+	    (uio->uio_resid != resid || error == 0 && resid != 0))
 		VTOI(ap->a_vp)->i_flag |= IN_ACCESS;
 	return (error);
 }
@@ -1903,12 +1913,14 @@ ufsfifo_write(ap)
 	} */ *ap;
 {
 	int error, resid;
+	struct inode *ip;
 	struct uio *uio;
 
 	uio = ap->a_uio;
 	resid = uio->uio_resid;
 	error = VOCALL(fifo_vnodeop_p, VOFFSET(vop_write), ap);
-	if (uio->uio_resid != resid)
+	ip = VTOI(ap->a_vp);
+	if (ip != NULL && (uio->uio_resid != resid || error == 0 && resid != 0))
 		VTOI(ap->a_vp)->i_flag |= IN_CHANGE | IN_UPDATE;
 	return (error);
 }