[src/trunk]: src/lib/libp2k Use NAMEI_INRENAME to improve the situation with ...

[pooka <pooka%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/6bd217082620
branches:  trunk
changeset: 750287:6bd217082620
user:      pooka <pooka%NetBSD.org@localhost>
date:      Wed Dec 23 01:11:39 2009 +0000

description:
Use NAMEI_INRENAME to improve the situation with detecting on when
to save componentname instead of looking at SAVESTART.  Not perfect,
but better.  Also, try to be more forgiving of kernel bugs.

diffstat:

 lib/libp2k/p2k.c |  45 ++++++++++++++++++++++++++-------------------
 1 files changed, 26 insertions(+), 19 deletions(-)

diffs (73 lines):

diff -r a0f33d30aa61 -r 6bd217082620 lib/libp2k/p2k.c
--- a/lib/libp2k/p2k.c  Wed Dec 23 01:09:57 2009 +0000
+++ b/lib/libp2k/p2k.c  Wed Dec 23 01:11:39 2009 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: p2k.c,v 1.31 2009/12/16 17:20:19 pooka Exp $   */
+/*     $NetBSD: p2k.c,v 1.32 2009/12/23 01:11:39 pooka Exp $   */
 
 /*
  * Copyright (c) 2007, 2008, 2009  Antti Kantee.  All Rights Reserved.
@@ -617,30 +617,37 @@
        RUMP_VOP_UNLOCK(dvp, 0);
        if (rump_pub_checksavecn(cn)) {
                /*
-                * XXX: detect RENAME by SAVESTART, both src and targ lookups
-                *
-                * XXX part deux: rename syscall actually does two lookups
-                * for the source, the second without SAVESTART.  So detect
-                * this also and compensate.
+                * XXX the rename lookup protocol is currently horribly
+                * broken.  We get 1) DELETE with SAVESTART 2) DELETE
+                * without SAVESTART 3) RENAME.  Hold on to this like
+                * it were the absolute truth for now.  However, do
+                * not sprinkle asserts based on this due to abovementioned
+                * brokenness -- some file system drivers might not
+                * even issue ABORT properly, so just free resources
+                * on the fly and hope for the best.  PR kern/42348
                 */
-               if (pcn->pcn_flags & NAMEI_SAVESTART) {
+               if (pcn->pcn_flags & NAMEI_INRENAME) {
                        if (pcn->pcn_nameiop == NAMEI_DELETE) {
-                               assert(p2n_dir->p2n_cn_ren_src == NULL);
-                               p2n_dir->p2n_cn_ren_src = cn;
+                               /* save path from the first lookup */
+                               if (pcn->pcn_flags & NAMEI_SAVESTART) {
+                                       if (p2n_dir->p2n_cn_ren_src)
+                                               freecn(p2n_dir->p2n_cn_ren_src,
+                                                   RUMPCN_FORCEFREE);
+                                       p2n_dir->p2n_cn_ren_src = cn;
+                               } else {
+                                       freecn(cn, RUMPCN_FORCEFREE);
+                                       cn = NULL;
+                               }
                        } else {
                                assert(pcn->pcn_nameiop == NAMEI_RENAME);
-                               assert(p2n_dir->p2n_cn_ren_targ == NULL);
+                               if (p2n_dir->p2n_cn_ren_targ)
+                                       freecn(p2n_dir->p2n_cn_ren_targ,
+                                           RUMPCN_FORCEFREE);
                                p2n_dir->p2n_cn_ren_targ = cn;
                        }
                } else {
-                       if (pcn->pcn_nameiop == NAMEI_DELETE
-                           && p2n_dir->p2n_cn_ren_src) {
-                               freecn(cn, RUMPCN_FORCEFREE);
-                               cn = NULL;
-                       } else {
-                               assert(p2n_dir->p2n_cn == NULL);
-                               p2n_dir->p2n_cn = cn;
-                       }
+                       assert(p2n_dir->p2n_cn == NULL);
+                       p2n_dir->p2n_cn = cn;
                }
        } else {
                freecn(cn, 0);
@@ -656,7 +663,7 @@
 
        p2n = getp2n(p2m, vp, false, NULL);
        if (p2n == NULL) {
-               if (pcn->pcn_flags & NAMEI_SAVESTART) {
+               if (pcn->pcn_flags & NAMEI_INRENAME) {
                        if (pcn->pcn_nameiop == NAMEI_DELETE) {
                                p2n_dir->p2n_cn_ren_src = NULL;
                        } else {