[src/trunk]: src/sys/kern Change "fli_alias" to point to the corresponding "f...

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

details:   https://anonhg.NetBSD.org/src/rev/0bf3b97a6c85
branches:  trunk
changeset: 449436:0bf3b97a6c85
user:      hannken <hannken%NetBSD.org@localhost>
date:      Thu Mar 07 11:09:10 2019 +0000

description:
Change "fli_alias" to point to the corresponding "fstrans_lwp_info".

Fix fstrans_clear_lwp_info() list traversal, remove already advanced
the list pointer.

diffstat:

 sys/kern/vfs_trans.c |  55 ++++++++++++++++++++++++++++-----------------------
 1 files changed, 30 insertions(+), 25 deletions(-)

diffs (126 lines):

diff -r 88117170ca41 -r 0bf3b97a6c85 sys/kern/vfs_trans.c
--- a/sys/kern/vfs_trans.c      Thu Mar 07 10:16:07 2019 +0000
+++ b/sys/kern/vfs_trans.c      Thu Mar 07 11:09:10 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vfs_trans.c,v 1.57 2019/03/01 09:02:03 hannken Exp $   */
+/*     $NetBSD: vfs_trans.c,v 1.58 2019/03/07 11:09:10 hannken Exp $   */
 
 /*-
  * Copyright (c) 2007 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_trans.c,v 1.57 2019/03/01 09:02:03 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_trans.c,v 1.58 2019/03/07 11:09:10 hannken Exp $");
 
 /*
  * File system transaction operations.
@@ -68,7 +68,7 @@
        struct fstrans_lwp_info *fli_succ;
        struct lwp *fli_self;
        struct mount *fli_mount;
-       struct mount *fli_alias;
+       struct fstrans_lwp_info *fli_alias;
        struct fstrans_mount_info *fli_mountinfo;
        int fli_trans_cnt;
        int fli_cow_cnt;
@@ -296,7 +296,7 @@
        /*
         * Scan our list clearing entries whose mount is gone.
         */
-       for (p = &curlwp->l_fstrans; *p; p = &(*p)->fli_succ) {
+       for (p = &curlwp->l_fstrans; *p; ) {
                fli = *p;
                if (fli->fli_mount != NULL &&
                    fli->fli_mountinfo->fmi_gone &&
@@ -308,11 +308,15 @@
                        fli->fli_mountinfo = NULL;
                        membar_sync();
                        fli->fli_self = NULL;
-
-                       if (*p == NULL)
-                               break;
+               } else {
+                       p = &(*p)->fli_succ;
                }
        }
+#ifdef DIAGNOSTIC
+       for (fli = curlwp->l_fstrans; fli; fli = fli->fli_succ)
+               if (fli->fli_alias != NULL)
+                       KASSERT(fli->fli_alias->fli_self == curlwp);
+#endif /* DIAGNOSTIC */
 }
 
 /*
@@ -321,7 +325,7 @@
 static struct fstrans_lwp_info *
 fstrans_alloc_lwp_info(struct mount *mp)
 {
-       struct fstrans_lwp_info *fli, *fli2;
+       struct fstrans_lwp_info *fli;
        struct fstrans_mount_info *fmi;
 
        for (fli = curlwp->l_fstrans; fli; fli = fli->fli_succ) {
@@ -373,10 +377,8 @@
        mutex_exit(&fstrans_mount_lock);
 
        if (mp) {
-               fli2 = fstrans_alloc_lwp_info(mp);
-               fli->fli_alias = fli2->fli_mount;
-
-               fli = fli2;
+               fli->fli_alias = fstrans_alloc_lwp_info(mp);
+               fli = fli->fli_alias;
        }
 
        return fli;
@@ -388,22 +390,17 @@
 static inline struct fstrans_lwp_info *
 fstrans_get_lwp_info(struct mount *mp, bool do_alloc)
 {
-       struct fstrans_lwp_info *fli, *fli2;
+       struct fstrans_lwp_info *fli;
 
        /*
         * Scan our list for a match.
         */
        for (fli = curlwp->l_fstrans; fli; fli = fli->fli_succ) {
                if (fli->fli_mount == mp) {
-                       if (fli->fli_alias != NULL) {
-                               for (fli2 = curlwp->l_fstrans; fli2;
-                                   fli2 = fli2->fli_succ) {
-                                       if (fli2->fli_mount == fli->fli_alias)
-                                               break;
-                               }
-                               KASSERT(fli2 != NULL);
-                               fli = fli2;
-                       }
+                       KASSERT((mp->mnt_lower == NULL) ==
+                           (fli->fli_alias == NULL));
+                       if (fli->fli_alias != NULL)
+                               fli = fli->fli_alias;
                        break;
                }
        }
@@ -943,9 +940,17 @@
                        printf(" (%s)", fli->fli_mount->mnt_stat.f_mntonname);
                else
                        printf(" NULL");
-               if (fli->fli_alias != NULL)
-                       printf(" alias (%s)",
-                           fli->fli_alias->mnt_stat.f_mntonname);
+               if (fli->fli_alias != NULL) {
+                       struct mount *amp = fli->fli_alias->fli_mount;
+
+                       printf(" alias");
+                       if (verbose)
+                               printf(" @%p", fli->fli_alias);
+                       if (amp == NULL)
+                               printf(" NULL");
+                       else
+                               printf(" (%s)", amp->mnt_stat.f_mntonname);
+               }
                if (fli->fli_mountinfo && fli->fli_mountinfo->fmi_gone)
                        printf(" gone");
                if (fli->fli_trans_cnt == 0) {