Re: [PATCH fs/locks 3 of 3] Fix race conditions with file lock vs close

[Olaf Kirch <okir@suse.de>]

On Mon, Jul 11, 2005 at 08:32:05AM -0400, Peter Staubach wrote:
> A different patch was submitted upstream already to address the fcntl/close
> race.  It was accepted into the '-mm' kernel on June 28'th.  That patch is
> attached.

I see, it seems this customer has been spamming just about everyone
about this problem :)

I just wonder how the following can work - your patch seems to drop
local book-keeping of locks completely, unless I misread it:


> +	if (filp->f_op && filp->f_op->lock != NULL)
>  		error = filp->f_op->lock(filp, cmd, file_lock);
> +	else {
> +		for (;;) {
> +			error = __posix_lock_file(inode, file_lock);
> +			if ((error != -EAGAIN) || (cmd == F_SETLK))
> +				break;
> +			error = wait_event_interruptible(file_lock->fl_wait,
> +					!file_lock->fl_next);
> +			if (!error)
> +				continue;
> +	
> +			locks_delete_block(file_lock);
>  			break;
> +		}
> +	}

This means if the application establishes an NFS lock, this will not
be reflected locally - and as a consequence, when the application just
exits, the lock will never be released.

Olaf
-- 
Olaf Kirch   |  --- o --- Nous sommes du soleil we love when we play
okir@suse.de |    / | \   sol.dhoop.naytheet.ah kin.ir.samse.qurax


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