The original smb.conf configuration is extended with:
comment = something
path = /mnt/storage
read only = No
Now, from an XP machine connecting to the home directory and copy a 1 GB file takes about 2 to 3 Minutes - ok. The same file from the storage share takes about 120 minutes. Replacing the path to /home/user/something and the file copy is fast again - So the problem is something with the other volume only.
Tried to ftp and copy 1 GB file from home and from /mnt/storage - both goes with 11 MB/sec fine.
The only difference is that /mnt/storage points to a software RAID5 array, both mounts are reiserfs.
I don't think this is a proper bug in Samba. Very likely it's some kind of configuration issue in your socket options, some reiserfs hickup or whatever. Without a lot more data (tcpdump, strace of the smbd, full smb.conf) we can't do much here.
Closing this bug as invalid, please do re-open if you have more information.