Re: 2.6.6-rc3-mm1

[Ian Kent]

On Mon, 3 May 2004, Jeff Moyer wrote:

> ==> Regarding Re: 2.6.6-rc3-mm1; raven@xxxxxxxxxx adds:
> 
> raven> The case where two process similtaneously trigger a mount in autofs4
> raven> can cause multiple requests to the daemon for the same mount. The
> raven> daemon handles this OK but it's possible an incorrect error to be
> raven> returned. For this reason I believe it is better to change the spin
> raven> lock to a semaphore in waitq.c. This makes the second and subsequent
> raven> request wait on the q as ther supposed to.
> 
> This looks good to me.  Do you also need to take the semaphore in
> autofs4_catatonic_mode(), around the hijacking of the queue?
> 
> void autofs4_catatonic_mode(struct autofs_sb_info *sbi)
> {
> 	struct autofs_wait_queue *wq, *nwq;
> 
> 	DPRINTK(("autofs: entering catatonic mode\n"));
> 
> 	sbi->catatonic = 1;
> 	wq = sbi->queues;
> 	sbi->queues = NULL;	/* Erase all wait queues */
> ...
>

Once sbi->catatonic is 1 then the mount is "catatonic". No more mount 
request can be made (ever). The q is quesient.

Interestingly, once done you can't return. Like jumping of a cliff and 
then deciding you don't want to hit the bottom.

The point of the may umount ioctl was to allow a decision to be made 
before jumping.

Ian

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