freebsd stable - May 2008 - FreeBSD 7.0-STABLE: "mount_nfs" vs "mount -t nfs": problems with second one, UDP timeouts and ICMP ports unreach?!

I have two hosts: host A (FreeBSD 6.3-S) and host B (FreeBSD 7.0-S, 
freshly installed).

   Host A exports "/usr/ports" to host B via NFS.

   Mount with "mount_nfs" works well:

b# mount_nfs a:/usr/ports /usr/ports
b# ls /usr/ports
[---SKIPPED---b#

   But mount with "mount -t nfs" FAILS:

b# mount -t nfs a:/usr/ports /usr/ports
[udp] a:/usr/ports: NFSPROC_NULL: RPC: Timed out
[udp] a:/usr/ports: NFSPROC_NULL: RPC: Timed out
^C
b#

   tcpdump on A shows VERY strange picture:

b.960 > a.sunrpc: UDP, length 56
a.sunrpc > b.960: UDP, length 28
b.820 > a.nfs: 40 null
a.nfs > b.820: reply ok 24
b > a: ICMP b udp port 820 unreachable, length 36
b.912 > a.sunrpc: UDP, length 56
a.sunrpc > b.912: UDP, length 28
b.973 > a.nfs: 40 null
a.nfs > b.973: reply ok 24
b > a: ICMP b udp port 973 unreachable, length 36

   You see? b answer with "UDP port unreachable" on each RPC reply!

   There is NO any firewalls on B. And, I repeat, it WORKS when I call 
mount_nfs directly in a moment!

   Main problem is, that "/etc/fstab" is processed by mount, and NFS 
mount hangs up on boot, as shown above :(

-- 
// Lev Serebryakov

Lev Serebryakov wrote:
>   You see? b answer with "UDP port unreachable" on each RPC
reply!
  Additional info.
  ktrace from "mount -t nfs":

============================================================  65962 mount_nfs
0.006679 RET   sendto 40/0x28
  65962 mount_nfs 0.006682 CALL 
kevent(0x4,0x638110,0x1,0x7fffffffe2d0,0x1,0x7fffffffe310)
  65962 mount_nfs 10.218001 GIO   fd 4 wrote 32 bytes
  65962 mount_nfs 10.218018 GIO   fd 4 read 0 bytes
        ""
  65962 mount_nfs 10.218023 RET   kevent 0
  65962 mount_nfs 10.218029 CALL  gettimeofday(0x7fffffffe320,0)
  65962 mount_nfs 10.218035 RET   gettimeofday 0
  65962 mount_nfs 10.218040 CALL  close(0x4)
  65962 mount_nfs 10.218049 RET   close 0
  65962 mount_nfs 10.218077 CALL  close(0x3)
  65962 mount_nfs 10.218087 RET   close 0
  65962 mount_nfs 10.218101 CALL  write(0x2,0x7fffffffdd40,0x37)
  65962 mount_nfs 10.218117 GIO   fd 2 wrote 55 bytes
        "[udp] gateway:/usr/ports: NFSPROC_NULL: RPC: Timed out
        "
============================================================
   ktrace (same piece) from "mount_nfs":
============================================================  93109 mount_nfs
0.005458 RET   sendto 40/0x28
  93109 mount_nfs 0.005462 CALL 
kevent(0x4,0x638110,0x1,0x7fffffffe2a0,0x1,0x7fffffffe2e0)
  93109 mount_nfs 0.005724 GIO   fd 4 wrote 32 bytes
  93109 mount_nfs 0.005738 GIO   fd 4 read 32 bytes
  93109 mount_nfs 0.005743 RET   kevent 1
  93109 mount_nfs 0.005748 CALL  recvfrom(0x3,0x638134,0x2260,0,0,0)
  93109 mount_nfs 0.005756 GIO   fd 3 read 24 bytes
  93109 mount_nfs 0.005761 RET   recvfrom 24/0x18
  93109 mount_nfs 0.005767 CALL  close(0x4)
  93109 mount_nfs 0.005775 RET   close 0
  93109 mount_nfs 0.005781 CALL  close(0x3)
  93109 mount_nfs 0.005788 RET   close 0
=============================================================

Lev Serebryakov wrote:
>   Main problem is, that "/etc/fstab" is processed by mount, and
NFS
> mount hangs up on boot, as shown above :(
   Mounting with "mount -t nfs" with 7.0 server (host B) and 6.3
client
(host A) works...

-- 
// Lev Serebryakov

Hello, freebsd-stable.
You wrote 16 ??? 2008 ?., 14:40:18:
>    There is NO any firewalls on B. And, I repeat, it WORKS when I call
> mount_nfs directly in a moment!
 Adding `-o -c' to mount (to pass `-c' to mount_nfs) helps. But I'm
very curious WHY mount_nfs, called directly, work WITHOUT `-c'...

-- 
// Black Lion AKA Lev Serebryakov <lev@FreeBSD.org>