[RFC] SUNRPC connect timeout case network request delay

[Mi Jinlong <mijinlong@cn.fujitsu.com>]

Hi,

When I use the nfs at RHEL with kernel-2.6.31 and nfs-utils-1.2.0, 
I got a problem, but i don't sure.

The process:

Step1: [22:40:9] Open file /mnt/nfs/file(OK)
Step2: [22:40:9] Lock file
       [22:40:9] Lock file success
Step3: [22:40:9] Reboot the nfs server
       If reboot success, put <enter> to continue
Step4: [22:42:16] Write data to file
       [22:42:16] Write data success
Step5: [22:42:16] Unlock file
       [22:46:30] Unlock file success.
Step6: [22:46:30] Close file /mnt/nfs/file
       [22:46:30] Close fiel /mnt/nfs/file success

The problem is at step5, unlock file takes 4 min, it's a long time than expected.
When traceing the kernel, I find SUNRPC call call_connect timeout many times, 
one timeout is 1min.

I think it's a problem of kernel, but i don't know why, can someone help me ?

thanks,
Mi Jinlong