posix-locks: running ls on file (or directory containing file) while file is being written causes failure

[Kevan Benson <kbenson@xxxxxxxxxxxxxxx>]

glusterfs 1.3.1 TLA 489 / Fuse 2.7.0 GLFS3

When writing a file from a client, an operation that does a listing on 
that file from another client while the file is being written causes the 
write operation to fail when the posix-locks feature is used.

I can replicate this with multiple config types, with AFR and Unify on 
the server, or on the client, or in the simplest case, with absolutely 
no special xlators besides posix-locks and a single server.  Here's the 
configs for that case:

Here's what it looks like:
# dd if=/dev/zero of=/mnt/glusterfs/testfile.10MB bs=1k count=10k
dd: writing `/mnt/glusterfs/testfile.10MB': Bad file descriptor
4006+0 records in
4005+0 records out
dd: closing output file `/mnt/glusterfs/testfile.10MB': Bad file descriptor

On the other client I'm simply running this to cause the error:
# ls /mnt/glusterfs/

Here's the configs for the simplest case:

# server.vol
volume share
       type storage/posix
       option directory /exports/test
end-volume

volume brick
       type features/posix-locks
       subvolumes share
end-volume

volume server
       type protocol/server
       option transport-type tcp/server
       option listen-port 6996
       subvolumes brick
       option auth.ip.brick.allow *
end-volume

volume trace
       type debug/trace
       subvolumes server
       option debug on
end-volume


# client.vol
volume brick
       type protocol/client
       option transport-type tcp/client
       option remote-host 172.16.1.81
       option remote-port 6996
       option remote-subvolume brick
end-volume