samba - Nov 2005 - Sudden problem with disconnects

I've been using a Samba share at home on my Linux box for about a year
which contains my music library. Until recently, I've not had any
problems whatsoever. As of the last week or two, I've gotten almost
constant disconnects from my Windows XP Home box when accessing files on
that share. To my knowledge, nothing has changed on either computer,
including Samba setup, firewalls, and the physical network.

The only difference I can think of is that I've started downloading and
viewing video podcasts from that share, which are typically Quicktime
movies approximately 50 MB in size, versus the size of a typical mp3
file. It is most often when viewing those movies that I lose my
connection, and I cannot reconnect without waiting a while or making
repeated attempts to map back to that drive.

I've tried a few modifications to my smb.conf file after searching the
web for similar issues, but nothing seems to fix the problem. I also
upgraded from 3.0.14 (on Debian Sarge) to 3.0.20bb (using Debian Sarge
package from samba.org)

Any help or suggestions would be greatly appreciated.


Changes I've tried in smb.conf:

adding TCP_NODELAY to "socket options"
adding level2 oplocks = true
adding write cache size = 262144


Global and share sections from my smb.conf:

[global]
        passwd program = /usr/bin/passwd %u
        printing = cups
        browseable = no
        dns proxy = no
        passdb backend = tdbsam guest
        encrypt passwords = true
        valid users = john
        socket options = TCP_NODELAY
        invalid users = root
        max log size = 1000
        preferred master = no
        obey pam restrictions = yes
        panic action = /usr/share/samba/panic-action %d
        passwd chat = *Enter\snew\sUNIX\spassword:* %n\n
*Retype\snew\sUNIX\spassword:* %n\n
        workgroup = HOME
        server string = %h server (Samba %v)
        syslog = 0
        log file = /var/log/samba/log.%m
        load printers = yes
        os level = 20
        interfaces = eth1
        default = global

[share]
        path = /tank/share
        valid users = john
        writeable = yes
        wide links = no

>From the time I'm able to connect until it disconnects, this is what I
always see in the log for the computer which gets disconnected (log.earth):

[2005/11/21 22:22:57, 1] smbd/service.c:make_connection_snum(662)
  earth (172.16.1.10) connect to service share initially as user john
(uid=1000, gid=1000) (pid 15030)
[2005/11/21 22:22:58, 0] smbd/service.c:make_connection_snum(575)
  Can't become connected user!
[2005/11/21 22:23:30, 0] smbd/service.c:make_connection_snum(575)
  Can't become connected user!
[2005/11/21 22:23:30, 0] smbd/service.c:make_connection_snum(575)
  Can't become connected user!
[2005/11/21 22:33:13, 1] smbd/service.c:make_connection_snum(662)
  earth (172.16.1.10) connect to service share initially as user john
(uid=1000, gid=1000) (pid 15327)
[2005/11/21 22:34:01, 0] lib/util_sock.c:read_data(526)
  read_data: read failure for 4 bytes to client 172.16.1.10. Error Connection
reset by peer
[2005/11/21 22:34:01, 1] smbd/service.c:close_cnum(835)
  earth (172.16.1.10) closed connection to service share