Re: [PATCH 16/20] xfs: pass a 64-bit count argument to xfs_iomap_write_unwritten

[Christoph Hellwig <hch@lst.de>]

On Mon, Feb 02, 2015 at 02:48:26PM -0500, J. Bruce Fields wrote:
> Previously: http://lkml.kernel.org/r/20150106175611.GA16413@lst.de
> 
> 	>       - any advice on testing?  Is there was some simple
> 	>       virtual setup that would allow any loser with no special
> 	>       hardware (e.g., me) to check whether they've broken the
> 	>       block server?
> 
> 	Run two kvm VMs that share the same disk.  Create an XFS
> 	filesystem on the MDS, and export it.  If the client has blkmapd
> 	running (on Debian it needs to be started manually) it will use
> 	pNFS for accessing the filesystem.  Verify that using the
> 	per-operation counters in /proc/self/mounstats.  Repeat with
> 	additional clients as nessecary.
> 
> 	Alternatively set up a simple iSCSI target using tgt or lio and
> 	connect to it from multiple clients.
> 
> Which sounds reasonable to me, but I haven't tried to incorporate this
> into my regression testing yet.

Additionally I can offer the following script to generate recalls,
which don't really happen during normal operation.  I don't
really know how to write a proper testcase that coordinates access
to the exported filesystem and nfs unless it runs locally on the same node,
though.  It would need some higher level, network aware test harness:

----- snip -----
#!/bin/sh

set +x

# wait for grace period
touch /mnt/nfs1/foo

dd if=/dev/zero of=/mnt/nfs1/foo bs=128M count=32 conv=fdatasync oflag=direct &

sleep 2

echo "" > /mnt/test/foo && echo "recall done"