[XFS] handle nfs requesting ino 0 gracefully

SGI Modid: xfs-linux:xfs-kern:179624a
Signed-off-by: Nathan Scott <nathans@sgi.com>

fs/xfs/linux-2.6/xfs_iops.c

@@ -225,26 +225,21 @@ linvfs_lookup(
 	struct dentry	*dentry,
 	struct nameidata *nd)
 {
-	struct inode	*ip = NULL;
-	vnode_t		*vp, *cvp = NULL;
+	struct vnode	*vp = LINVFS_GET_VP(dir), *cvp;
 	int		error;
 
 	if (dentry->d_name.len >= MAXNAMELEN)
 		return ERR_PTR(-ENAMETOOLONG);
 
-	vp = LINVFS_GET_VP(dir);
 	VOP_LOOKUP(vp, dentry, &cvp, 0, NULL, NULL, error);
-	if (!error) {
-		ASSERT(cvp);
-		ip = LINVFS_GET_IP(cvp);
-		if (!ip) {
-			VN_RELE(cvp);
-			return ERR_PTR(-EACCES);
-		}
+	if (error) {
+		if (unlikely(error != ENOENT))
+			return ERR_PTR(-error);
+		d_add(dentry, NULL);
+		return NULL;
 	}
-	if (error && (error != ENOENT))
-		return ERR_PTR(-error);
-	return d_splice_alias(ip, dentry);
+
+	return d_splice_alias(LINVFS_GET_IP(cvp), dentry);
 }
 
 STATIC int

fs/xfs/linux-2.6/xfs_super.c

@@ -570,7 +570,6 @@ linvfs_get_parent(
 	int			error;
 	vnode_t			*vp, *cvp;
 	struct dentry		*parent;
-	struct inode		*ip = NULL;
 	struct dentry		dotdot;
 
 	dotdot.d_name.name = "..";
@@ -580,21 +579,13 @@ linvfs_get_parent(
 	cvp = NULL;
 	vp = LINVFS_GET_VP(child->d_inode);
 	VOP_LOOKUP(vp, &dotdot, &cvp, 0, NULL, NULL, error);
-
-	if (!error) {
-		ASSERT(cvp);
-		ip = LINVFS_GET_IP(cvp);
-		if (!ip) {
-			VN_RELE(cvp);
-			return ERR_PTR(-EACCES);
-		}
-	}
-	if (error)
+	if (unlikely(error))
 		return ERR_PTR(-error);
-	parent = d_alloc_anon(ip);
-	if (!parent) {
+
+	parent = d_alloc_anon(LINVFS_GET_IP(cvp));
+	if (unlikely(!parent)) {
 		VN_RELE(cvp);
-		parent = ERR_PTR(-ENOMEM);
+		return ERR_PTR(-ENOMEM);
 	}
 	return parent;
 }

fs/xfs/xfs_vfsops.c

@@ -1582,31 +1582,35 @@ xfs_vget(
 	vnode_t		**vpp,
 	fid_t		*fidp)
 {
-	xfs_fid_t	*xfid;
+	xfs_mount_t	*mp = XFS_BHVTOM(bdp);
+	xfs_fid_t	*xfid = (struct xfs_fid *)fidp;
 	xfs_inode_t	*ip;
 	int		error;
 	xfs_ino_t	ino;
 	unsigned int	igen;
-	xfs_mount_t	*mp;
 
-	xfid  = (struct xfs_fid *)fidp;
-	if (xfid->xfs_fid_len == sizeof(*xfid) - sizeof(xfid->xfs_fid_len)) {
-		ino  = xfid->xfs_fid_ino;
-		igen = xfid->xfs_fid_gen;
-	} else {
-		/*
-		 * Invalid.  Since handles can be created in user space
-		 * and passed in via gethandle(), this is not cause for
-		 * a panic.
-		 */
+	/*
+	 * Invalid.  Since handles can be created in user space and passed in
+	 * via gethandle(), this is not cause for a panic.
+	 */
+	if (xfid->xfs_fid_len != sizeof(*xfid) - sizeof(xfid->xfs_fid_len))
 		return XFS_ERROR(EINVAL);
-	}
-	mp = XFS_BHVTOM(bdp);
+
+	ino  = xfid->xfs_fid_ino;
+	igen = xfid->xfs_fid_gen;
+
+	/*
+	 * NFS can sometimes send requests for ino 0.  Fail them gracefully.
+	 */
+	if (ino == 0)
+		return XFS_ERROR(ESTALE);
+
 	error = xfs_iget(mp, NULL, ino, XFS_ILOCK_SHARED, &ip, 0);
 	if (error) {
 		*vpp = NULL;
 		return error;
 	}
+
 	if (ip == NULL) {
 		*vpp = NULL;
 		return XFS_ERROR(EIO);