deadlocks with fallocate

[Thomas Neumann]

> Can you try if the hack below makes the problem go away?
> 
> 
> Index: linux-2.6/fs/xfs/linux-2.6/xfs_aops.c
> ===================================================================
> --- linux-2.6.orig/fs/xfs/linux-2.6/xfs_aops.c	2009-10-14
>  17:06:50.489254023 +0200 +++
>  linux-2.6/fs/xfs/linux-2.6/xfs_aops.c	2009-10-14 17:07:54.055006445 +0200
>  @@ -278,6 +278,8 @@ xfs_end_bio_unwritten(
>  	xfs_off_t		offset = ioend->io_offset;
>  	size_t			size = ioend->io_size;
> 
> +	current->flags |= PF_FSTRANS;
> +
>  	if (likely(!ioend->io_error)) {
>  		if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) {
>  			int error;
> 

I did some more tests, and indeed the patch makes the deadlock go away. Your 
description of it as a hack makes me somewhat concerned about using it 
permanently, but hopefully you will find a proper solution ;)

Thanks for looking at this.