On Mon, Feb 28, 2011 at 10:27:23AM -0500, Rick Koshi wrote:
>
> Hi all, I hope this is the right place for this.
>
> I'm using NFSv4, server and client both running 2.6.36.
>
> I've found that when I lock an NFS-mounted file on a client, the server
> reserves an open file descriptor (as seen in /proc/sys/fs/file-nr).
So it looks like that's the total number of allocated struct file's
across the system?
> The server never releases this descriptor, even if the client process
> explictly releases the lock or exits.
>
> In my case, I noticed this because I have a monitoring process which
> runs every 5 seconds and runs 'rrdtool' to log some status to a file
> on an NFS-mounted filesystem. This allocated 720 files per hour, and
> eventually caused my server to run out of file descriptors and become
> unusable. I experimented with a test program, and found that it's the
> fcntl64(3, F_SETLK, {type=F_WRLCK, ...}) system call that triggers
> the behavior, and that unlocking the file explictly doesn't help.
>
> Stopping the NFS service (including the lockd) does not release the
> open files. Only rebooting resets the state.
>
> I'm no kernel expert. Perhaps you can tell me if this is a necessary
> side effect of some part of the NFS implementation. But to me, it looks
> like a bug.
Looks like I can reproduce something similar. Yes, looks like a bug to
me.
Is there any earlier kernel where you know this problem *didn't* occur?
--b.
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