Jan Willem Stumpel wrote:
Ron Johnson wrote:On 07/19/08 04:46, Jan Willem Stumpel wrote:[..]Now my theory is that the switch-off problem occurs after the following events: 1 - I mount the remote usb drive. 2 - my wife switches off her computer. 3 - I try to umount the remote usb drive -- this cannot be done.I suppose the shutdown program also tries to umount nfs mounts, but fails, and then instead of skipping this step, just hangs. Does this make sense? If so, is there a way to solve this problem?Manually "umount -l" the remote drive before you shutdown?This does not work. Manually umounting the nfs drive (after the computer which hosts the nfs drive is switched off) just leads to a hang, whether the "lazy" switch is applied or not. In fact I cannot even type the umount command entirely: the system hangs immediately after typing the first 3 characters (including the leading /) of the mount point.
This hanging at "cannot even type the umount command entirely: the system hangs immediately after typing the first 3 characters" sounds very strange.
The NFS subsystem can't know that a umount has been entered until the shell takes the full command line, forks a copy of itself and then execs the new command. At least, that's how I understand things. ;)
I'd suggest focusing on this, though I have no good suggestions for debugging it. The only thing I can think of is to run a subshell under strace, to a file, and try the umount in the subshell. Perhaps there'll be something there to indicate what's going on.
I've never worked with strace and an interactive program like a shell, so you may not get much from the above. You could force non-interactive operation by using the shell '-c' argument:
strace -o nfs_hang.trace -f bash -c 'umount /...' &By backgrounding the program, you should get a prompt from which you can issue a 'kill' to the 'bash' process. If you can kill it, then strace should print to and close the trace file "normally".
<<deleted NFS comments>>
Regards, Jan
-- Bob McGowan
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