Subject: Re: hangs on boot in 9984d7394618df9

From: Al Viro <[email-masked]>
Date: Mon, 8 Apr 2013 23:57:15 +0100

On Mon, Apr 08, 2013 at 11:46:37PM +0100, Al Viro wrote:

> Very interesting...  Just in case, could you try this on top of that
> branch and see if it triggers?
> 
> diff --git a/fs/pipe.c b/fs/pipe.c
> index 8ce279b..b6cd51b 100644
> --- a/fs/pipe.c
> +++ b/fs/pipe.c
> @@ -1022,6 +1022,11 @@ static int fifo_open(struct inode *inode, struct file *filp)
>  	/* We can only do regular read/write on fifos */
>  	filp->f_mode &= (FMODE_READ | FMODE_WRITE);
>  
> +	if (inode->i_sb->s_magic == PIPEFS_MAGIC) {
> +		WARN_ON(filp->f_flags & O_NONBLOCK);
> +		filp->f_flags &= ~O_NONBLOCK;
> +	}

*d'oh*

OK, I'm an idiot.  I see what's going on now...  Give me a few and I'll push
a fix.