[src/trunk]: src/lib/libukfs mfs is a bit off in the sense that mount(2) does...

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

details:   https://anonhg.NetBSD.org/src/rev/5bf4ae676bc8
branches:  trunk
changeset: 752861:5bf4ae676bc8
user:      pooka <pooka%NetBSD.org@localhost>
date:      Mon Mar 08 12:38:14 2010 +0000

description:
mfs is a bit off in the sense that mount(2) doesn't return since
mfs uses the mounting process for the backing store memory.  I
guess mfs could be fixed to just reference the process vmspace and
let it return, but that would probably cause wait() to return for
other worms.  So it's easier to dance according to mfs's tune: if
mounting mfs, create a thread for extra execution context.

diffstat:

 lib/libukfs/ukfs.c |  73 ++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 files changed, 68 insertions(+), 5 deletions(-)

diffs (95 lines):

diff -r 1aee5e589ea2 -r 5bf4ae676bc8 lib/libukfs/ukfs.c
--- a/lib/libukfs/ukfs.c        Mon Mar 08 12:35:08 2010 +0000
+++ b/lib/libukfs/ukfs.c        Mon Mar 08 12:38:14 2010 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ukfs.c,v 1.48 2010/03/05 18:49:30 pooka Exp $  */
+/*     $NetBSD: ukfs.c,v 1.49 2010/03/08 12:38:14 pooka Exp $  */
 
 /*
  * Copyright (c) 2007, 2008, 2009  Antti Kantee.  All Rights Reserved.
@@ -501,6 +501,30 @@
        return rv;
 }
 
+struct mountinfo {
+       const char *mi_vfsname;
+       const char *mi_mountpath;
+       int mi_mntflags;
+       void *mi_arg;
+       size_t mi_alen;
+       int *mi_error;
+};
+static void *
+mfs_mounter(void *arg)
+{
+       struct mountinfo *mi = arg;
+       int rv;
+
+       rv = rump_sys_mount(mi->mi_vfsname, mi->mi_mountpath, mi->mi_mntflags,
+           mi->mi_arg, mi->mi_alen);
+       if (rv) {
+               warn("mfs mount failed.  fix me.");
+               abort(); /* XXX */
+       }
+
+       return NULL;
+}
+
 static struct ukfs *
 doukfsmount(const char *vfsname, const char *devpath, struct ukfs_part *part,
        const char *mountpath, int mntflags, void *arg, size_t alen)
@@ -544,11 +568,50 @@
                regged = 1;
        }
 
-       rv = rump_sys_mount(vfsname, mountpath, mntflags, arg, alen);
-       if (rv) {
-               rv = errno;
-               goto out;
+       /*
+        * MFS is special since mount(2) doesn't return.  Hence, we
+        * create a thread here.  Could fix mfs to return, but there's
+        * too much history for me to bother.
+        */
+       if (strcmp(vfsname, MOUNT_MFS) == 0) {
+               pthread_t pt;
+               struct mountinfo mi;
+               int i;
+
+               mi.mi_vfsname = vfsname;
+               mi.mi_mountpath = mountpath;
+               mi.mi_mntflags = mntflags;
+               mi.mi_arg = arg;
+               mi.mi_alen = alen;
+
+               if (pthread_create(&pt, NULL, mfs_mounter, &mi) == -1) {
+                       rv = errno;
+                       goto out;
+               }
+
+               for (i = 0;i < 100000; i++) {
+                       struct statvfs svfsb;
+
+                       rv = rump_sys_statvfs1(mountpath, &svfsb, ST_WAIT);
+                       if (rv == -1) {
+                               rv = errno;
+                               goto out;
+                       }
+
+                       if (strcmp(svfsb.f_mntonname, mountpath) == 0 && 
+                           strcmp(svfsb.f_fstypename, MOUNT_MFS) == 0) {
+                               break;
+                       }
+                       usleep(1);
+               }
+       } else {
+               rv = rump_sys_mount(vfsname, mountpath, mntflags, arg, alen);
+               if (rv) {
+                       rv = errno;
+                       goto out;
+               }
        }
+
        mounted = 1;
        rv = rump_pub_vfs_getmp(mountpath, &fs->ukfs_mp);
        if (rv) {